January 13, 2020

How many cultivated plants are marked as such on iNaturalist?

Thought I'd try to address this question with a semi-scientific approach:

For the past year (1/12/2020 - 1/12/2019) in a 25 square-mile square centered on Blacksburg, VA:

To the best of my ability to determine, there have been:

131 certainly cultivated, marked wild (plants in orderly rows in flower beds, landscape plantings, hanging baskets, houseplants, exotic trees not known to spread from cultivation, etc.)
90 probably cultivated, marked wild (mostly street trees and commonly cultivated plants that could conceivably be escapes or otherwise wild, but are almost certainly planted, just lacking in enough photo context clues to be certain)
1150 probably wild, marked wild (when in doubt, or totally confused, I chose this category)
131 certainly cultivated, marked cultivated
5 probably wild, marked casual (for some reason other than "captive/cultivated")
2 probably wild, marked cultivated (both were chickory, which were growing as weeds in a lawn)

...so for 1509 tracheophytes in the Blacksburg area:

76%-83% observations were of wild plants;
17%-23% observations were of cultivated plants;

of the cultivated plants:
37% were definitely incorrectly marked as wild;
62% were likely incorrectly marked as wild.
37% were definitely correctly marked as wild.

Posted on January 13, 2020 02:09 by ddennism ddennism | 4 comments | Leave a comment

October 08, 2019

Goldenrod Galls

Solidago and Euthamia are two plant genera commonly called goldenrods. They host a number of gall-making insects. These insects have not been collected into a single document online, though someone started to do so on bugguide a few years ago.

This journal entry is my attempt to catalog all the gall-making insects on goldenrods. This is probably never going to be an exhaustive list, but I'm striving to include as many as I can find. I'm defining "gall" as a structure primarily composed of plant tissue that is induced by a resident insect and is not otherwise produced. This definition is a little wishy-washy, and could include other stem-borers and leafminers, for example, if one really wants to split hairs, but I have excluded those creatures for now. This is not an identification guide for all insect residents of goldenrod galls; many times the current resident(s) of a gall are not the original gall-makers! In some types of galls parasitoids and inquilines are more commonly reared than the gall-maker.

This entry was motivated by my observation in summer 2019 that many identifications of Rhopalomyia solidaginis summer galls were probably misidentified on iNaturalist. I think the computer vision was partly to blame for this; it likely got a little aggressive and started suggesting R. solidaginis for diverse images. This included identifications on observations of normal rosettes from plants from a variety of families (Asparagaceae to Campanulaceae) with no evidence of an insect or gall even being present. People also may have been unaware of the great diversity of gall-midges and other gall-makers on these genera, selecting R. solidaginis by default for any leafy gall on a goldenrod.

That said, many observations of galls on Solidago and Euthamia don't seem to match those of any known species of gall-maker. There may be quite a few out there to be discovered.

Charley Eiseman has a great series on his blog about goldenrod rosette bud galls:
https://bugtracks.wordpress.com/2011/04/15/goldenrod-rosette-galls/
https://bugtracks.wordpress.com/2012/08/09/goldenrod-rosette-galls-part-2/
https://bugtracks.wordpress.com/2013/02/21/goldenrod-rosette-galls-part-3/

The above-mentioned bugguide page is here: https://bugguide.net/node/view/324012

Much of this information comes from the published work of Netta Dorchin (see full reference list at bottom).

() = uncertainty in the literature about whether this is a host species, or a note that it more rarely/conditionally serves as a host.

(()) = host not mentioned in literature, but I suspect there might be some iNat observations of this species serving as a host.



Gall-making insects on Euthamia ("goldentops", "grass-leaved goldenrods")

gall-making insect host gall gall description representative images sources
Asphondylia pseudorosa E. graminifolia bud
capitulum
leaf-snap
Vegetative bud galls are usually formed at the apex, but can also be found on lateral buds. The outer leaves are broadened, the innermost leaves form the gall-chamber, which is lined with white mycelium. The innermost leaves eventually turn black. Unlike in R. lobata galls, spongy tissue does not form, and each bud gall contains only one larva.

Capitulum bud galls form later in the season. These are difficult to distinguish from normal, developing capitula, though they do not flower, and instead house the developing larva. These are also lined with white mycelium.

Leaf-snap galls are pictured in Dorchin et al. (2015) but not mentioned in the text. They appear to be formed at the terminal bud, and are presumably also lined with fungus.
See Figs. 15-17 in Dorchin et al. (2015) Dorchin et al. (2015)
Asteromyia euthamiae Euthamia leaf spot
(stem spot)
Black blisters on leaves (and rarely on stems?). The blisters are lined with a white mycelium. There are several generations per year. photo of Asteromyia carbonifera galls on Euthamia leaves by cassi saari
photo by cassi saari (@bouteloua) (CC BY-NC 4.0)
photo of Asteromyia euthamiae galls on a Euthamia leaf by Ethan Maitra
photo by Ethan Maitra (@astrobirder)(CC BY-NC 4.0)
photo of Asteromyia euthamiae galls on Euthamia stems by Ethan Maitra
photo by Ethan Maitra (@astrobirder)(CC BY-NC 4.0)
Stireman et al. (2010)
Dasineura carbonaria E. graminifolia bud Shoot tip bud galls, loose, with twisted and/or inrolled leaves. Dorchin et al. (2007), Dorchin et al. (2009b)
Epiblema desertana E. graminifolia stem Very narrow stem swellings. Miller (1963)
Rhopalomyia lobata E. graminifolia bud Multi-chambered galls in apical and lateral buds. They start as 1 cm globular swellings within shoot tips or clustered around the shoot tips. Several leaves surround the spongy mass at the gall base, which grows to 6 cm. Eventually the leaves loosen and the whitish tissue reveals 5-35 larval chambers. The leaves continue beyond the gall, thinning towards the apex. R. lobata galls on lateral buds of Euthamia photo by Jason Michael Crockwell
photo by Jason Michael Crockwell (@berkshirenaturalist)(CC BY-NC-ND 4.0)
R. lobata galls clustered and fused at the apical buds of Euthamia photo by Christian Grenier
photo by Christian Grenier (@krisskinou) (CC0 1.0)
Dorchin et al. (2009)
Rhopalomyia pedicellata E. graminifolia variable Pod-like structures attached to stems, leaves, and/or inflorescences. Delicate, slender gall with a single chamber. Green to purplish-red with longitudinal ridges, tapered at both ends. Proximal end has a long, slender stalk ('pedicel') that attaches to the rest of the plant. Two generations per year at least. close up shot of R. pedicellata gallphoto by Ethan Maitra (@astrobirder)(CC BY-NC 4.0)
context shot of R. pedicellata gallsphoto by Sara Rall (@srall)(CC BY-NC 4.0)
Dorchin et al. (2009)
Rhopalomyia fusiformae E. graminifolia,
E. tenuifolia
variable Same as those of R. pedicellata, but without a pedicel, often lacking even some of the bottom tapering section, appearing as though welded to the host tissue. This minor difference in gall shape correlates with differences in insect morphology. My note: I wonder how these two species diverged when they are found on the same hosts in roughly the same geographic range? context shot of many R. fusiformae galls
photo by Ethan Maitra (@astrobirder )(CC BY-NC 4.0)
Dorchin et al. (2009)

Gall-making insects on Solidago (most other "goldenrods")

gall-making insect host gall gall description representative image sources
Asphondylia monacha S. juncea,
S. erecta,
S. uliginosa,
S. altissima
bud Early Spring Generation (only observed on S. altissima): Bud galls directly off of rhizomes at the soil line: wider and harder than normal buds, single chamber lined with white mycelium. Or, slightly later in the season, bud galls at the tip of longer sprouts, stunting them and making them slightly thickened.

Summer Generation (on S. juncea, S. erecta, S. uliginosa, but NOT S. altissima): Much more conspicuous apical rosette bud galls, lined with mycelium, 15-30 rosette-units, forming a spherical gall complex at the shoot apex. Occasionally found on lateral buds on S. uliginosa, but rarely found there on other host species. S. uliginosa-derived adults were smaller in size as well. The authors speculate that these might represent a separate species (but distinct from the S. uliginosa-galling Asphondylia entity below.)
see Figs. 1-2 in Dorchin et al. (2015) for early spring generation; Figs. 3-4 for later generation.
A. monacha bud gall clustersummer generation gall cluster
photo by Tom Norton (@tsn)(CC BY-NC 4.0)
Dorchin et al. (2015)
Asphondylia rosulata S. rugosa,
(S. gigantea)
leaf snap
bud
Spring-Early Summer: Snap Galls (both hosts): Multiple leaves appear joined together at a blistering point (actually the leaves are "glued" together when the leaves are very young) to make a single chamber lined with white mycelium. Unlike those produced by A. solidaginis, this species' leaf-snap galls are often located very near the plant apex, giving rise to a gradient of gall morphology, from leaf snap to bud galls. This gradient is visible in the example observation.

Mid-Late Summer: Bud galls (only on S. rugosa) and only on apical buds. A single, conical chamber in the middle of a rosette of leaves. The chamber is lined with white mycelium. These galls are smaller and flatter than those formed by R. solidaginis on S. rugosa, and are composed of fewer leaves. Unlike those of R. solidaginis, this species' galls contain a single chamber.
See Fig. 11-14 in Dorchin et al. (2015) for images of leaf snap and terminal bud galls by this species.
An observation of a gradient of A. rosulata galls, from leaf-snap galls to a bud gall, on Solidago rugosa by Ashley M Bradfordbud gall and leaf-snap galls on Solidago rugosa in TN
photo by Ashley M Bradford (@ashley_bradford) (CC BY-NC 4.0)
Dorchin et al. (2015)
Asphondylia silva S. caesia bud Very small, single-chambered bud galls at shoot tips. Several very short leaves press together to form a single, mycelium-lined chamber. See Fig. 19-20 in Dorchin et al. (2015) for images of terminal bud galls by this species. Dorchin et al. (2015)
Asphondylia solidaginis S. altissima,
(S. gigantea)
leaf snap
bud
Spring-Early Summer: Snap Galls (both hosts): Multiple leaves appear joined together at a blistering point (actually the leaves are glued together while the leaves are very young) to make a single chamber lined with white mycelium.

Mid-Late Summer: Bud galls (only on S. altissima) on apical and/or axillary buds (3-5 cm in diameter), with a single, conical chamber in the middle that is lined with white mycelium. Unlike in Rhopalomyia solidaginis galls, the central chamber is not obscured by the surrounding modified leaves; it is visible without dissection. The gall walls are lined with thick white mycelia. The surrounding rosette of bunched leaves is also smaller in size, and flatter (not tufted). R. solidaginis bud galls usually contain several chambers per gall; those of A. solidaginis contain a single chamber.
A. solidaginis leaf snap galls photo by Lena Struweleaf snap galls
photo by Lena Struwe (@vilseskog ) (CC BY-NC 4.0)
A. solidaginis bud gall photo by Timothy Freybud gall
photo by Timothy Frey (@calconey)(CC BY-NC 4.0)
Dorchin et al. (2015)
Asphondylia sp.1 (S. bicolor-galler) S. bicolor bud A. monacha-like galls (and insects) that are distinct from A. monacha according to a molecular phylogenetic analysis. Could be the same species as A. sp. "S. sempervirens-galler". One insect from an S. uliginosa rosette gall also sorted into this clade, while others from that host species sorted into A. monacha. S. bicolor galler gall imagegall cluster on S. bicolor
See also Fig. 6 in Dorchin et al. (2015).
Dorchin et al. (2015)
Asphondylia sp.1 (S. sempervirens-galler) S. sempervirens bud A. monacha-like galls (and insects) that are distinct from A. monacha according to a molecular phylogenetic analysis. Could be the same species as A. sp. "S. bicolor-galler". One S. uliginosa rosette gall adult also sorted into this clade, while others sorted into A. monacha. Unlike A. monacha, this species also makes lateral bud galls. See Charley Eiseman's (@ceiseman) blog post for a photo by Noah Charney of this gall, along with details of its discovery and insects reared from it.
See also Fig. 5 in Dorchin et al. (2015) for a photo of these terminal bud galls.
Dorchin et al. (2015)
Asphondylia sp.1 (S. uliginosa-galler) S. uliginosa bud See comments for A. "S. sempervirens-galler" and A. "S. bicolor-galler". Distinct, at least, from A. monacha, though that species also forms rosette bud galls on S. uliginosa Dorchin et al. (2015)
Asphondylia sp. 2 S. nemoralis leaf snap Leaf snap galls observed rarely on this species, but insect responsible is unknown Dorchin et al. (2015)
Asphondylia sp.2 S. tortifolia* bud A. rosulata-like galls in October, but insect unknown Dorchin et al. (2015)
Asphondylia sp.2 S. patula bud Aggregated bud galls with mini-rosettes, like those made by A. monacha, have been observed on this species, but the insect remains unknown. Could be A. monacha, or another gall-maker. These observations of bud galls on S. patula may or may not be the same galls referred to by Dorchin et al. (2015): https://www.inaturalist.org/observations/34507741; https://www.inaturalist.org/observations/36565595 Dorchin et al. (2015)
Asphondylia sp.2 S. odora bud Aggregated bud galls like those made by A. monacha have been observed on this species, but the insect remains unknown. Could be A. monacha, or another insect. My note: on iNaturalist, Alvin Diamond (@adiamond) has observed galls in Alabama on S. odora that resemble R. solidaginis bud galls on S. altissima. These may or may not be the same S. odora galls Dorchin et al. (2015) refer to. Dorchin et al. (2015), this iNat observation
Asteromyia carbonifera Solidago leaf spot Black blisters on leaves, lined internally with a white mycelium. Lots of interesting evolutionary biology research has been done in this system, particularly in the lab of John Stireman at Wright State University, that I look forward to diving into. Different lineages of A. carbonifera induce differently-shaped galls. The fungus that comprises the mycelium that lines the interior of these galls is Botryosphaeria dothidea. photo by Matt Parr of Asteromyia carbonifera gall on Solidago leafphoto by Matt Parr (@ginsengandsoon) (CC BY-NC-SA 4.0)
photo of Asteromyia carbonifera gall on Solidago leaf by Ethan Maitra
photo by Ethan Maitra (@astrobirder)(CC BY-NC 4.0)
photo of Asteromyia carbonifera galls on Solidago leaf by Chuck Sexton
photo by Chuck Sexton (@gcwarbler)(CC BY-NC 4.0)
Stireman et al. (2010)
bugguide
Asteromyia modesta Solidago,
Erigeron,
Conyza**,
Grindelia,
Symphyotrichum
leaf spot Leaf blisters. Probably polyphyletic as currently circumscribed, with two distinct clades, one of which is itself polyphyletic with the recognition of A. tumifica. Both clades included some individuals that made galls on Solidago. "Galls" might be an overstatement; the larvae reside in cryptic pockets of leaf tissue that may be purple but are often nearly the same green color as the surrounding leaf tissue. The chambers are lined with a thin mycelium. Charley Eiseman (@ceiseman) accidentally reared this midge from a leaf with more prominent leaf-mines, and photographed both the blister and the midge. Stireman et al. (2010)
Bug Tracks post
Asteromyia tumifica Solidago stem Spongy outgrowth that partially or wholly encircles a stem. Can be very low on stem. Nested within one of two A. modesta clades, rendering that clade paraphyletic, so perhaps this insect taxon will be folded into a revised concept of A. modesta in the future. Stireman et al. (2010)
Dasineura folliculi S. rugosa,
S. gigantea
bud Shoot tip bud galls that resemble other bud galls, but are looser and show evidence of feeding (yellowish spots) on the distal portions of the gall leaves D. folliculi bud gallon S. gigantea - I am unsure of this identification, but it does resemble photos of such galls in the cited literature. Dorchin et al. (2007), Dorchin et al. (2009b)
Epiblema scudderiana S. altissima, Solidago spp.
Heterotheca subaxillaris
stem Narrowly cylindrical-ellipsoid stem-swelling galls. Sometimes irregularly shaped. Two holes. One small one near the top and close to a leaf axil. This is the entry hole. Another hole gets larger through the season. This is the frass-ejection and eventual exit hole. This" bung hole" is blocked with caterpillar-derived material that fits the hole closely and resembles a train wheel. Univoltine; larvae overwinter in the gall. Before winter, the caterpillar spins a silk funnel that guides the emerging moth to the exit hole. Branches often proliferate at or above the gall. But see also Lasioptera galls. photo by David of Epiblema scudderiana gall on Solidago stemphoto by David (@davidenrique) (CC BY-NC-SA 4.0)
Miller (1963); Miller (1976)Brown et al. (1983)
Eurosta comma S. juncea,
S. missouriensis,
(S. rugosa)
rhizome Swellings on rhizomes very near soil line. Sometimes peanut-like in outline. S. rugosa was reported as a host for Eurosta elsa (Phillips 1923, Novak & Foote (1980)), which modern sources synonymize with E. comma. bugguide, Cedar Creek (2000), Novak & Foote (1980)
Eurosta cribrata S. juncea,
S. sempervirens
rhizome "Crown Gall" that begins basically at the soil line (or just under), but grows upwards and is mostly above-ground at maturity. Like those of E. comma, the galls resemble peanuts somewhat. My note: Are S. juncea and S. sempervirens really hosting the same fly species? bugguide, Arthr. Fl., Sutton & Steck (2005)
Eurosta fenestra ? rhizome Sutton & Steck (2005) say that this is also a member of the E. comma species complex. They mention that it's probably never actually been found in FL, despite earlier reports, which were due to misidentifications of E. floridensis or other members of the E. comma species complex. Sutton & Steck (2005)
Eurosta floridensis S. fistulosa rhizome Galls are similar to those made by E. comma and E. fenestra. Arth. Fl., Sutton & Steck (2005)
Eurosta lateralis S. chapmanii stem Similar to galls made by E. solidaginis. Only known from Brevard Co., FL, at least recently. Sutton & Steck (2005) state that it may be critically endangered. They give S. odora as the host, but that was before S. chapmanii was segregated from that species. They point out a very old record by Wiedemann (1830) also possibly of this species in the "Indien" (sic) River area of Florida. Arth. Fl., Sutton & Steck (2005)
Eurosta solidaginis S. altissima,
S. gigantea,
(S. canadensis),
(S. rugosa)
stem Round, nearly spherical stem galls. Exterior vestiture depends on host species; hairy in S. altissima (presumably also hairy in S. canadensis and S. rugosa), smooth and shiny in S. gigantea. There is a great wealth of literature on the evolutionary dynamics at play in this system. Briefly, gall diameter seems to be under the control of the insect's genetics, not the host plant's. Insects that produce galls with larger diameters are more likely to survive attack by parasitic wasps, whose ovipositors are unable to penetrate the thicker galls. However, larger galls are more attractive to bird predators. There is also interesting research on host-species specialization by different populations of this fly (on S. altissima vs. on S. gigantea), and the divergent selection at play during this process. The galls are so frequent on S. altissima in the mid-Atlantic, that the presence of galls has been suggested as a character for distinguishing S. altissima plants from S. canadensis, although S. canadensis can also be (rarely?) a host for this fly. E. solidaginis stem gallon S. altissima Bucknell Solidago Gall Website, Moffatt et al. (2019), Stoltzfus (1989)
Eutreta hespera Solidago sp. rhizome Reared once from rhizomes of an unknown Solidago species near Custer, SD, but the flies have been collected from the Dakotas westward, through much of western NA. Stoltzfus (1974)
Eutreta novaeboracensis S. altissima,
(S. rugosa)
(Solidago spp.)
rhizome Larvae bore through rhizomes and above-ground stems, inducing galls. The stem-borers emerge earlier than the rhizome-borers (and are bivoltine rather than univoltine), so these two groups might represent cryptic sister species. Stem-galls can be found near the ground, sometimes described as crown galls. "Eutreta sparsa" is sometimes attributed to these and other galls on North American Astereae, but this is actually a South American species that probably does not make galls on Solidago, instead associating with Stachytarpheta branches. bugguide, Stoltzfus (1974)
Gnorimoschema gallaeasterella S. flexicaulis
(S. caesia)
Eurybia divaricata
Doellingeria umbellata
probably others
stem Stem galls similar to those of S. gallaesolidaginis, but with brown bung holes (? - implied in Miller (1963)). Need to find a print copy of Miller (2000) to read more about this genus. Judd (1962) could not find any galls on S. caesia despite there being large numbers of these plants adjacent to and within the S. flexicaulis site with many galls. I think it's likely that the initial report of galls from S. caesia may be in error since these two Solidago species were frequently confused/lumped early on. Then again, the Eurybia and Doellingeria host reports suggest a wider range of acceptable hosts. Nazari & Landry (2012)
Judd (1962)
Gnorimoschema gallaesolidaginis S. altissima,
S. canadensis
stem Ellipsoid (wider than those of Epiblema) stem galls with a characteristic white exit bung-hole. Miller (1963) mentions that there are other species in this genus that make galls on other Solidago species. His monograph on them (2000) lists eight species, most of which are on Solidago. Later, Heard & Kitts (2012) compared G. gallaesolidaginis on S. altissima and S. gigantea. Nason et al. (2002) considered this to either contain a single differentiating species (into semispecies) onto the two respective host-groups (S. altissima / canadensis and S. gigantea), or two barely-isolated cryptic species, in which case see G. jocelynae for more. Need to find a print copy of Miller (2000) to read more about this genus. photo of Gnorimoschema gallaesolidaginis spindle gall on Solidago stem by Colin D Jones
photo by Colin D Jones (@colindjones) (CC BY-NC 4.0)
Miller (1963)
Heard & Kitts (2012)
Nazari & Landry (2012)
Gnorimoschema gallaespeciosum (S. speciosa)
(S. jejunifolia)
(S. rigidiuscula)
stem? Mentioned in passing in Nazari & Landry (2012). Need to find a print copy of Miller (2000) to read more about this genus. Type specimen is from Ramsey Co., MN, which is out-of-range for S. speciosa in the new, strict sense. The host is probably S. jejunifolia and/or S. rigidiuscula. This gall has the bung-hole located just above the middle of the gall - unlike its relatives. Nazari & Landry (2012)
Gnorimoschema gibsonella S. rigida,
(Symphyotrichum pilosum)
stem S. rigida for the type. Nazari & Landry (2012) cite Miller (2000) for additional host. Need to find a print copy of Miller (2000) to read more about this genus. Nazari & Landry (2012)
Gnorimoschema jocelynae S. gigantea stem This is the name Miller (2000) gave to the host-race derived from G. gallaesolidaginis, when that species established a cryptic sister species on S. gigantea (Nason et al. 2002). The only difference is in the bung hole coloration - which was determined by the adult's ancestral host species, not its current host species in Miller (2000), however, Nason et al. (2002) points out that these exit hole characteristics could be idiosyncratic to particular plants and Miller's N was only 3 for this experiment. Need to find a print copy of Miller (2000) to read more about this genus. Works after Nason et al. (2002) tend to refer to these moths as G. gallaesolidaginis, gigantea host-race. Nazari & Landry (2012)
Gnorimoschema salinaris S. sempervirens,
S. missouriensis
S. juncea
other members in this species group
stem S. gigantea is also a host according to one MI record in Nazari & Landry (2012), but this might be G. gallaesolidaginis / G. jocelynae. Need to find a print copy of Miller (2000) to read more about this genus. Nazari & Landry (2012)
Lasioptera solidaginis Solidago stem Irregular, elongate stem-swelling galls. Makes a small exit hole on the side of the gall. But see also Epliblema galls. bugguide
Procecidochares anthracina S. californica bud bud galls cluster on stem near where the stem emerges from rhizomes. Usually buried in humus, but not truly subterranean. Univoltine, unlike P. atra. Goeden & Teerink (1997)
Procecidochares atra S. altissima,
S. gigantea,
S. rugosa,
(Erigeron canadensis),
(Aster*** sp.)
bud Spring Generation: Large stem galls at the base of the host-plant containing several larvae.

Summer Generation: Lateral bud galls that look like artichokes initially, and eventually open as the fly matures. The terminal bud is also sometimes galled, but usually in addition to lateral galls. (My observation: When the terminal bud is galled, it is often much larger than the accompanying lateral galls.) Gall chamber is large and not sealed; somewhat open at the distal end. The chamber has the appearance of being inset into the stem somewhat. At maturity, the rosette of leaves surrounding the gall have typically flattened and grown away from the gall, no longer giving the gall an artichoke-like appearance. (My note: At this stage, these galls, particularly the terminal ones, can superficially resemble those of Rhopalomyia solidaginis and Asphondylia solidaginis. However, these midge-galls create very different-looking chambers, which are set atop the host stem rather than appearing hollowed-out within thickened stem-like tissue.) Each gall has only one larva, unlike in the spring generation. Probably has many other hosts, including some outside Solidago.
P. atra bud gallssummer generation gall cluster on S. altissima
P. atra bud gall vertical sectionsummer generation, vertical section through terminal bud gall
P. atra bud gallssummer generation gall cluster on S. altissima
wikipedia, iNat obs, bugguide, Philips and Smith (1998)
Procecidochares polita (S. virgata)
(S. chrysopsis)
bud? stem? Aldrich (1929) says that accounts of this species being raised from Solidago are in error, and actually refer to P. atra due to some nomenclatural confusion at the time in the literature. However, Ibrahim (1980) attributes this species to Solidago stricta stem galls collected in Dade County, FL. At that time, "Solidago stricta" would have referred to what is now known as S. virgata or possibly S. chrysopsis at that location (see John Semple's website for details). There are an older records for a collection in the Jacksonville, FL area (Sutton & Steck 2005) and Falls Church, VA area (Aldrich 1929). Sutton & Steck (2005) cautions that many details in Ibrahim (1980) are inaccurate and repeat known mistakes from earlier literature, though they don't talk about the P. polita record specifically. The adult flies are apparently easily distinguished from P. atra morphologically; the entire legs are yellow rather than yellow with black femora. None of these sources describes the gall. Aldrich (1929), Ibrahim (1980), Sutton & Steck (2005)
Rhopalomyia anthophila S. altissima capitulum Capitulum (flower-head) galls among the inflorescence of the host. Cylindrical, or like a truncated cone. Fuzzy and whitish. Inner chamber conical with thin walls. photo of an isolated R. anthophila gall
photo by Kevin Keegan (@kevinliam)(public domain)context shot of many R. anthophila galls
among S. altissima capitula
macro image of R. anthophila galls by Dan Mullen
photo by Dan Mullen (CC BY-NC-ND 2.0)
Dorchin et al. (2009)
Rhopalomyia bulbula S. juncea bud Only a spring generation is known, but the insect is presumably multivoltine;
Spring Generation: "Clustered on rhizomes, at the bases of spring shoots. The gall resembles a bud, with acute apex and base. Surface is smooth and white, with green stripes where exposed to light." Single chambered.
Dorchin et al. (2009)
Rhopalomyia capitata S. gigantea,
S. leavenworthii,
(S. altissima),
((S. canadensis))
bud Spring Generation: Few (1-8) conical chambers surrounded by disorganized small leaves, sheathed (initially at least, sometimes loosening) by several wide leaves. Distinctly more conspicuous than R. solidaginis spring galls.

Summer Generation: Apical bud gall with many small leaves of uniform length in the middle, surrounding many (6-20) closed larval chambers. Wide leaves also sheath these galls. The uniformly-small leaves give the overall gall complex a flat-topped appearance. Whereas tufts of leaves that comprise the summer generation gall complex formed by R. solidaginis form discernible mini-rosettes, each surrounding a larval chamber, in R. capitata the gall leaves are not obviously so-organized, perhaps as a consequence of there being many more chambers.

My side note: In the upper Great Lakes region there are leafy galls on S. gigantea that more closely resemble those made by R. solidaginis.
See Fig. 74 in Dorchin et al. (2009) for an image of the spring generation gall.
R. capitata bud gallsummer generation
R. capitata bud gall, vertical sectionsummer generation bud gall, vertically sectioned
photo by hallm (@hallm) (CC BY-NC 4.0)
R. capitata bud gall in MNsummer generation bud gall, from above, in MN
photo by Miriam Kniaz (@miriamkniaz) (CC BY-NC 4.0)
Dorchin et al. (2009)
Rhopalomyia clarkei S. rugosa,
S. altissima
leaf out-growth
stem out-growth
Small, conical, single-chambered. Usually on abaxial leaf surface, but can also appear on adaxial surface or on stems. When on leaves, attached at a major vein. Green to yellow-green and covered with hairs. Very young galls with a tuft of hair at base. Multivoltine. Less frequent on S. altissima. (My observation: There are several gall observations on iNaturalist that fit this description, and are currently identified as R. clarkei, but they do not all closely resemble one another. They may represent different stages of development, or else different presentations on different host species.) See Figs. 62-65 of Dorchin et al. (2009) for additional images of these galls at various stages of development on S. rugosa and S. altissima.
R. clarkei leaf gall photo by Will Van Hemessen
photo by Will Van Hemessen (@wdvanhem) (CC BY-NC 4.0)
Dorchin et al. (2009)
Rhopalomyia cruziana (S. spathulata),
(S. velutina)
capitulum? From an unknown gall from an unidentified Solidago species growing in the Santa Cruz mountains in California. Dorchin (2009) infers that the gall is probably a capitulum gall because the adult insects closely resemble other capitulum-gallers in this genus. Dorchin et al. (2009)
Rhopalomyia gina S. juncea leaf outgrowth Like R. clarkei galls, but usually on upper side of leaf and with a corresponding scar or little tail on the opposite side. Hairless, probably reflecting the vestiture of the host plant. See Figs. 68-69 in Dorchin et al. (2009) for images. My note: Fig. 69 shows a leaf with what might be pubescence on the abaxial surface (in addition to the normal cilia at the leaf margin), which makes me wonder whether this is really S. juncea. Dorchin et al. (2009)
Rhopalomyia guttata S. bicolor capitulum Hidden among normal-looking inflorescence pedicels of neighboring capitula. Galls are conical-cylindrical, droplet-shaped, smooth, white-to-green or sometimes red. Tapering apically. Galled capitula are wider and harder to the touch than ungalled ones. Unlike R. anthophila galls, these retain the capitulum's pedicel. Dorchin et al. (2009)
Rhopalomyia hirtipes S. juncea bud Forms fleshy bud galls at the shoot apex, often arresting shoot growth while the plant is still very short. Gall initially has a tapered tip, but this disappears with growth. The whole gall eventually becomes ovoid and reminiscent of a potato. Spongy and usually multi-chambered. See also R. thompsonii for a similar gall that appears earlier in the season and mostly underground. R. hirtipes bud gall photo by catherineklatt
photo by Catherine Klatt (@catherineklatt)(CC BY-NC 4.0)
R. hirtipes bud gall photo by Charles and Kathy Appell showing the plant flowering from lateral buds under the gall.
not always arresting growth
photo by Charles and Kathy Appell (@charleshappell) (CC BY-NC 4.0)
Dorchin et al. (2009)
Rhopalomyia inquisitor S. gigantea leaf outgrowth? Originally described as an inquiline in R. capitata galls, but this could not be replicated by Dorchin et al. (2009). The did notice R. clarkei-like galls (except smooth-surfaced) on S. gigantea, though, particularly on leaves from within Dasineura follicularis galls. Conjecture that these R. clarkei-like galls might be the real galls occupied by this species. Perhaps Felt (the original describer) confused D. follicularis galls with R. capitata galls, and then concluded that R. inquisitor was an "inquilines" that way? However, Dorchin et al. (2009) were unable to rear any adults from these R. clarkei-like galls on S. gigantea, so the galls where R. inquisitor resides remain unclear. An example of these galls is probably shown here: https://www.inaturalist.org/observations/744023 by Sara Rall (@srall). See Figs. 66-67 in Dorchin et al. (2009) for reference images. Dorchin et al. (2009)
Rhopalomyia racemicola S. altissima,
(S. fistulosa)
capitulum Green, bristly, onion-shaped capitulum galls, sometimes found in aggregations. Galls on S. fistulosa were tentatively identified as this species by Raymond Gagné . Dorchin et al. (2009)
Rhopalomyia solidaginis S. altissima,
S. canadensis,
S. rugosa,
((S. odora))
bud Spring Generation: Inconspicuous, shoot tip rosette bud-galls, often stunting the shoot. Unlike the later generation, these typically enclose a single, white, conical gall-chamber, but sometimes several gall-chambers are connected longitudinally.

Summer generation: Each of multiple (2-5) chambers is surrounded by a group of very short and narrow leaves, which are in turn surrounded by longer and wider leaves to form a distinct rosette-subunit within the gall complex. The whole complex itself forms a conspicuous mass of leaves. This is a very common gall in the mid-Atlantic states.
Alvin Diamond (@adiamond) has observed similar galls on S. odora in Alabama; I'm not sure whether these are the galls that Dorchin (2015) refers to and suspects an Asphondylia midge of making (see Asphondylia entries above) or if this is a distinct entity.
See Figs. 70, 72 in Dorchin et al. (2009) for images of spring generation galls. R. solidaginis bud gall vertical sectionsummer generation
R. solidaginis bud gall vertical sectionsummer generation, vertical section
Dorchin et al. (2009)
Rhopalomyia thompsoni S. altissima rhizome bud Spring Generation: Solitary or clustered, bulbous, fleshy masses with 1-8 chambers each. Start on rhizomes (underground) but become apparent above ground by emergence time in early May.

Second Generation: Brownish, globular multi-chambered swellings of the rhizomes that stay underground until late September when they become apparent above the soil surface for adult emergence. Both galls and adults resemble R. hirtipes.
Dorchin et al. (2009)
Rhopalomyia sp. (S. fistulosa-stem-galler) S. fistulosa stem Aggregated stem galls, each gall a hairy grayish oval, with a single chamber each. The whole aggregate commonly has a star-like structure. They appear most similar to R. racemicola galls. Might be responsible for the gall in this observation: https://www.inaturalist.org/observations/31507758 Dorchin et al. (2009)
Schizomyia racemicola Solidago capitulum Greenish-purplish onion-shaped capitulum galls alongside normal capitula in the inflorescence. Gall exterior is smooth. Gall-maker larva is bright red-orange. It exits the gall as a larva and pupates elsewhere. S. racemicola gall on S. ulmifoliaon S. ulmifolia
S. racemicola gall on S. altissimaon S. altissima
bugguide

Some records of Trupanea infesting goldenrod flower-heads, but do they form galls?
See also Aster Yellows phytoplasma, which can induce phyllody in Solidago.

*observed in Maryland (??)
**I think this Conyza species is probably C. canadensis, which is back in Erigeron now.
***probably refers to Symphyotrichum species now, not Aster sensu lato.

1These entries are for insects that induced galls that resembled those of A. monacha, but were found on other host Solidago species, and were divergent phylogenetically.
2These entries are for the un-studied (to my knowledge) insects that induce Asphondylia-like galls on other host Solidago species. These are known only from the appearance of galls on these goldenrods; the midges themselves have been neither reared nor described. These entries may represent infestation by known Asphondylia midges, A. monacha and A. solidaginis in particular, on occasional/accidental host species. I myself have observed Asphondylia-like galls on S. patula. They may also represent unrelated gall-making organisms.

Unexpected / Interesting goldenrod gall observations

Rhopalomyia solidaginis-like bud gall on Solidago chapmanii: https://www.inaturalist.org/observations/37226412

Asphondylia monacha-like bud gall on Solidago leavenworthii:
https://www.inaturalist.org/observations/36869277

bud-gall on Solidago sp. (?) in Kansas:
https://www.inaturalist.org/observations/34869212

Asphondylia monacha-like bud galls on Solidago sempervirens:
https://www.inaturalist.org/observations/35173501
https://www.inaturalist.org/observations/16081294
(probably the same bud-galler discovered by Charley Eiseman here:
https://bugtracks.wordpress.com/2012/08/09/goldenrod-rosette-galls-part-2/
and in the above table as: "Asphondylia sp. (S. sempervirens-galler)"

bud-gall on Solidago juncea (?):
https://www.inaturalist.org/observations/35173440

tiny bud-galls on Solidago ulmifolia (?) in IL:
https://www.inaturalist.org/observations/33584564
https://www.inaturalist.org/observations/33623087

Asphondylia-like bud galls on southeastern USA Solidago sp., possibly A. monacha on S. erecta:
https://www.inaturalist.org/observations/33794356
https://www.inaturalist.org/observations/34156586
https://www.inaturalist.org/observations/17063696
https://www.inaturalist.org/observations/31258368
https://www.inaturalist.org/observations/31420378

Rhopalomyia fusiformae on Euthamia graminifolia sort of far from Ithaca, NY:
https://www.inaturalist.org/observations/33794356

Asphondylia monacha-like bud gall cluster on Solidago sp. in VA:
https://www.inaturalist.org/observations/35246250

Asphondylia monacha-like bud gall cluster on Solidago altissima (?) in NJ:
https://www.inaturalist.org/observations/34508254
...or very, very large R. solidaginis galls, I guess. More-typical looking examples of R. solidaginis in immediate vicinity: https://www.inaturalist.org/observations/34507741
Could also be R. capitata but on an atypical host species (host is definitely not S. gigantea), and the gall is not flat-topped.
A similar situation in N IL:
https://www.inaturalist.org/observations/28883789

Asphondylia solidaginis-like leaf deformities (and maybe a snap-gall?) on Solidago sp. in MS:
https://www.inaturalist.org/observations/12472658

A very tightly-wound Asphondylia solidaginis-like gall:
https://www.inaturalist.org/observations/14392656

Is this Asphondylia rosulata on Solidago rugosa?
https://www.inaturalist.org/observations/29881623

not Procecidochares atra, looks kind of like Dasineura, but lateral galls present in addition to terminal gall, on S. altissima in OH:
https://www.inaturalist.org/observations/32848998

Dasineura-like leaf deformities in spring in TX:
https://www.inaturalist.org/observations/24096959

A strange bud gall on Solidago in CT:
https://www.inaturalist.org/observations/33925735

A bud gall on Solidago way out-of-range in Washington State:
https://www.inaturalist.org/observations/13619060

Rhopalomyia anthophila-like gall chamber, but not on the inflorescence, in MI:
https://www.inaturalist.org/observations/15411274

Rhopalomyia solidaginis-like bud galls in appearance, but on S. gigantea in MN:
https://www.inaturalist.org/observations/17081514
https://www.inaturalist.org/observations/29258718
and in MA:
https://www.inaturalist.org/observations/31895692

Asphondylia-like bud galls on S. rigida (?) in IL:
https://www.inaturalist.org/observations/18784886
https://www.inaturalist.org/observations/32639920

bud gall on Solidago ptarmicoides in Ontario:
https://www.inaturalist.org/observations/19331736

Rhopalomyia capitata on a Solidago species that is not S. gigantea:
https://www.inaturalist.org/observations/31247515




References


Aldrich (1929):
https://repository.si.edu/bitstream/handle/10088/15820/1/USNMP-76_2799_1929.pdf

Arth. Fl. = Arthropods of Florida website by Florida State Museum of Entomology:
http://www.fsca-dpi.org/Diptera/Families/Tephritidae/Species/Eurosta/eurosta_cribrata.htm

Bucknell University Eurosta biology page:
http://www.projects.bucknell.edu/solidago/main.html

Cedar Creek Ecosystem Science Reserve (2000):
http://cedarcreek.umn.edu/insects/029061n.html

Dorchin et al. (2007):
Netta Dorchin, Carolyn E. Clarkin, Eric R. Scott, Michael P. Luongo, Warren G. Abrahamson, Taxonomy, Life History, and Population Sex Ratios of North American Dasineura (Diptera: Cecidomyiidae) on Goldenrods (Asteraceae), Annals of the Entomological Society of America, Volume 100, Issue 4, 1 July 2007, Pages 539–548, https://doi.org/10.1603/0013-8746(2007)100[539:TLHAPS]2.0.CO;2

Dorchin et al. (2009):
https://www.mapress.com/j/zt/article/view/zootaxa.2152.1.1

Dorchin et al. (2009b):
Dorchin, N., Scott, E. R., Clarkin, C. E., Luongo, M. P., Jordan, S. and Abrahamson, W. G. (2009) Behavioural, ecological and genetic evidence confirm the occurrence of host‐associated differentiation in goldenrod gall‐midges. Journal of Evolutionary Biology, 22: 729-739. doi:10.1111/j.1420-9101.2009.01696.x

Dorchin et al. (2015):
Dorchin, N., Joy, J. B., Hilke, L. K., Wise, M. J., Abrahamson, W. G. (2015) Taxonomy and phylogeny of the Asphondylia species (Diptera: Cecidomyiidae) of North American goldenrods: challenging morphology, complex host associations,
and cryptic speciation. Zoological Journal of the Linnean Society, 174: 265-304. doi:10.1111/zoj.12234
https://academic.oup.com/zoolinnean/article/174/2/265/2449766

Heard & Kitts (2012):
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.726.1531&rep=rep1&type=pdf

Ibrahim (1980):
https://ufdcimages.uflib.ufl.edu/AA/00/02/97/95/00001/AA00029795_00001.pdf

Goeden & Teerink (1997):
https://www.biodiversitylibrary.org/part/55666#/summary

Miller (1963):
https://kb.osu.edu/bitstream/handle/1811/4921/V63N02_065.pdf

Moffat et al. (2019):
https://link.springer.com/article/10.1007/s10682-018-9966-z

Philips and Smith (1998):
https://www.biodiversitylibrary.org/part/13377#/summary

Phillips (1923): https://www.jstor.org/stable/pdf/25003994.pdf

Stireman et al. (2010):
https://doi.org/10.1016/j.ympev.2009.09.010

Stoltzfus (1974):
https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=6120&context=rtd

Stoltzfus (1989):
https://scholarworks.uni.edu/cgi/viewcontent.cgi?article=1587&context=jias

Sutton & Steck (2005):
http://journals.fcla.edu/mundi/article/viewFile/25075/24406

All unattributed photos are my own.

Posted on October 08, 2019 06:53 by ddennism ddennism | 17 comments | Leave a comment

September 11, 2018

Two Texas Toadshades

Trillium gracile, and T. ludovicianum may both be present in eastern Texas. These are my notes for distinguishing them from one another, taken from the monograph where John Freeman first described T. gracile and clarified the previously-hazy description of T. ludovicianum. Where metrics are given, I have omitted the extreme values, providing only the "typical" ranges (not in parentheses). Other Trillium also occur in Texas. By "leaves" I mean, technically, "bracts".

T. gracile T. ludovicianum
scape
scape length : leaf length 3.2 - 3.5 2.4 - 2.8
leaf
shape elliptic
(elliptic-ovate to elliptic-oblong)
lanceolate or
broadly ovate
sepal
length 18 - 26 mm 24 - 40 mm
apex shape acuminate-blunt or obtuse acute or acute-rounded
petal
length 21 - 35 mm 35 - 55 mm
stamen
anther sac
dehiscence
introrse latrorse
pollen color creamy - yellow olive - orange
anther connective
prolongation
short-beaked short-rounded
gynoecium
carpel-height : stamen-length barely exceeding 0.5 ≥ 0.75
ovary x-section 3-angled 6-angled
stigma length 2.0 - 4.5 mm 4.5 - 10 mm
stigma attachment divergent
extending ovary outline into lyre-shape
initially continuous in outline with ovary
bending distal to point of attachment
fruit
outline smooth often prominently 6-ridged

I have seen comments suggesting that clump-formation and overall plant size differ between the two species, with T. ludovicianum being both more likely to form clumps and generally taller. These are not mentioned in Freeman's monograph. He gives an overlapping range of scape lengths for the two species, with T. gracile being actually taller on average (though it has petals that are about 2 cm shorter):

Trillium gracile: (16-) 20-32.5 (-36) cm long scapes
Trillium ludovicianum: (10-) 15-28 (-37) cm long scapes

Singlehurst et al. (2003) summarized the occurrences of Trillium in Texas. Changes from Freeman's monograph germane to their separation by morphology:

1. T. gracile is listed as having elliptic to broadly ovate leaves.
2. T. ludovicianum is listed as having clump-forming tendencies lacking in T. gracile

The two species are probably at least partially temporally isolated with T. gracile blooming later: late Mar -May vs. late Feb - early Apr.

Posted on September 11, 2018 19:03 by ddennism ddennism | 0 comments | Leave a comment

August 10, 2018

Uvularia

U. grandiflora U. perfoliata U. sessilifolia U. puberula U. floridana
leaf attachment perfoliate perfoliate sessile sessile sessile
tepal planar curvature whole tepal twirls along long axis, apex may flare tepal margins may roll outwards, apex may flare apex may flare apex may flare tepal twirls distally along long axis, apex may flare
tepal abaxial surface smooth raised orange-yellow bumps smooth smooth smooth
stem cross-section at nodes terete terete angled angled, with rough puberulence along ridges angled
leaf abaxial surface pubescent glabrous-glaucous glabrous-glaucous puberulent(-glabrous) glabrous

U. floridana also has a leaf-like bract (very, very near the flower) that is absent in its close relatives (U. sessilifolia, U. puberula)

Posted on August 10, 2018 19:25 by ddennism ddennism | 1 comments | Leave a comment

June 26, 2018

Two Erigeron in PA

Erigeron annuus and Erigeron strigosus are the two Erigeron species in PA with tapering leaf bases (rather than clasping leaves).

Flora of PA treatment uses vague descriptors to distinguish them (what constitutes "numerous leaves"?) that might be useful once the user is already familiar with the two.

Flora of North America entry (Guy Nesom, 2004) quickly distinguishes them from other Erigeron based on lack of pappus on ray florets, but not disc florets . This is pictured in my observation.
http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=112000&key_no=5
It then emphasizes stem vestiture, which might not be visible in many observations on iNaturalist. Even this emphasis includes quite a bit of overlap, apparently to accommodate some varieties of E. strigosus and to accommodate the fact that E. annuus sometimes has strigose hairs too.

Michigan Flora gets around this problem by ignoring the problematic E. strigosus var. septentrionalis (associating it with some forms of E. annuus), which makes for a cleaner couplet, but who knows? it might be an oversimplification:

"E. annuus: Middle region of stem glabrate to pubescent with all or many of the hairs long (0.5–1.2 mm) and spreading; principal cauline leaves usually elliptic to ovate, ca. 10–35 (–40) mm wide, with a few large teeth.

E. strigosus: Middle region of stem moderately to densely pubescent with only short (0.5 mm or less) mostly appressed-antrorse hairs; principal cauline leaves linear to oblanceolate, ca. 2.5–10 (–15) mm wide, entire."

https://michiganflora.net/genus.aspx?id=Erigeron

Posted on June 26, 2018 00:34 by ddennism ddennism | 2 observations | 0 comments | Leave a comment

March 28, 2018

Two Blue Cohosh Species

Caulophyllum thalictroides and Caulophyllum giganteum are separate species according, as far as I can tell, mostly to this paper. However, it occurs to me, reading this paper, that physiological effects of early emergence could confound the determination of the morphological details used in this study.

For example, if the emergence and flowering phenology of C. giganteum is earlier, and if the vegetative characters that supposedly distinguish the species continue to expand and grow, as do many forest herbs, then the vegetative characters could appear larger for supposed C. giganteum plants just as a consequence of their head-start. This could be a problem as long as all the plants in this part of the study were sampled on the same day-of-the-year, rather than day-since-emergence (they were).

"On the collection date of the mass sample, 11 May 1982, C. giganteum had completed flowering while C. thalictroides was in anthesis." But how were such plants assigned species-identifications, then? Hopefully not by the same morphological characters that were used in the PCA!

The vegetative morphological characters in the single-population experiment:

Vegetative differences in C. giganteum (all longer and/or bigger):
1. leaflet length and width of the first two leaves
2. leaflet sinus length of the first two leaves
3. primary petiolule length of the first two leaves
4. terminal inflorescence length
5. and a decrease in the degree of compounding of the second leaf.

The authors also show that flower size differences distinguish the species. (This part is from herbarium specimens across the ranges of all three species in the genus.)
1. stamen length
2. sepal length
3. pistil length
4. petal length
5. ratio of filament length to anther length
(but you shouldn't use ratios in this type of analysis)

In this case, they found convincing evidence of a bimodal distribution along PCA1 (composed of the above 5 characters, in decreasing order of importance, and with the same positive valence), which suggests two morphologically distinct species, one big-flowered and one small-flowered. However, this shows no evidence of the claimed phenological separation, and doesn't really show evidence of other traits that supposedly differentiate the species (flower number per inflorescence, perianth color). Herbarium specimens are not always the most representative examples of a given population, and there may well have been plants in the C. giganteum populations that had smaller flowers that were less conspicuous to the collectors.

A common greenhouse experiment might be necessary to determine whether there really is separation here, and I'd like to see evidence that organ expansion has completed by the time of its determination in the first part of this study. But maybe first I should observe some of these populations for myself:

The closest Caulophyllum locations to me:
https://www.inaturalist.org/observations/2000688

For my late April trip to Shenandoah:

on the way down:
https://www.inaturalist.org/observations/8032969
https://www.inaturalist.org/observations/3807980
https://www.inaturalist.org/observations/7097471
https://www.inaturalist.org/observations/838935
https://www.inaturalist.org/observations/7646865

in and around Shenandoah:
https://www.inaturalist.org/observations/5100770
https://www.inaturalist.org/observations/3885367
https://www.inaturalist.org/observations/6133924
https://www.inaturalist.org/observations/4799201
https://www.inaturalist.org/observations/5645425

Posted on March 28, 2018 19:43 by ddennism ddennism | 3 comments | Leave a comment

March 16, 2018

Three Similar Toadshades in SE USA

Trillium decipiens, T. reliquum , and T. underwoodii form a group of three closely related species. Here are my notes for distinguishing them from one another, taken from the monograph where the other two were first segregated from a broader concept of T. underwoodii.

T. decipiens T. underwoodii T. reliquum
stalk (scape)
carriage
erect erect decumbent*
stalk : leaf
length ratio
2.5 - 3.0
tall-appearing,
leaf tips don't touch ground
1.0 - 2.5
short-appearing,
leaf tips often touch ground
1.6 - 2.0
short-appearing,
leaf surfaces at or near ground level
sepal
carriage at flowering
divergent-spreading horizontal,
or curving back down to touch leaves
variable
length : width ratio 3.0 - 3.5 3.5 - 4.0 3.5 - 4.0
petal
shape
broadly oblanceolate - obovate narrowly oblanceolate to narrowly elliptic usually narrowly elliptic,
but variable
length : width ratio 2 - 3 3.5 - 5 3.5 - 4
occasionally broader
color highly variable, from
green to yellow-purple to brown-purple
brown-purple
(rarely yellowish)
brown-purple
bronze
(rarely yellowish)
anther sac dehiscence lateral lateral introrse
stamen : carpel
height ratio
≈ 1.5 ≈ 1.5 ≥ 2
leaf shape lanceolate
(straight line from widest point to apex)
lanceolate
(straight line from widest point to apex)
broadly elliptic
(convex curve from widest point to apex)

*not nearly as decumbent as Trillium decumbens. In the T. reliquum population I visited, the stalk (scape) will sometimes only hint at 'laxness' with a slight 'S' bend, but at least some plants in a given population should have scapes that grow initially along the ground.

Posted on March 16, 2018 23:25 by ddennism ddennism | 2 observations | 0 comments | Leave a comment

February 21, 2018

Distinguishing Yellow Trout Lilies in E USA

It's easy to distinguish our three yellow trout lilies from one another when they are in-fruit, or dug-up. But what about when they're in-bloom? You know, when you notice them?

The presence of stolons can be inferred from the number of one-leaved, 'sterile' plants in a population. The stolon-producing species often produce carpets of plants in this stage; E. umbilicatum subsp. umbilicatum will only produce the occasional cluster of steriles, which are either same-aged siblings (clustered by a single fruit dispersal event) or offsets.

Clifford Parks and James Hardin (1963) carried out an exhaustive study of their floral characteristics and correlated them to stolon production, ploidy, and capsule shape. I thought the results of their paper might be very useful to iNaturalists. They are summarized here:

E. rostratum E. americanum E. umbilicatum
subsp. umbilicatum
E. umbilicatum
subsp. monostolum
tepal carriage agape strongly reflexed strongly reflexed strongly reflexed
flower angle erect nodding nodding nodding
stolons 1+ 1+ 0 1
capsule shape
in profile
strongly beaked
("rostrate")
rounded, truncate,
or apiculate
indented
("umbilicate")
indented
rarely merely truncate
capsule presentation held erect not erect
but still held off the ground
reclining on the ground reclining on the ground
or rarely just above
petal bases clearly auricled
encircling filaments
minutely auricled
or toothed
not auricled not auricled,
but margin irregular
green coloration
on abaxial side of tepals
none none or slight none present
pale spot
at base of inside of tepals
absent absent in 90%
otherwise vague or small
always present,
but sometimes small
always present
often prominent and large
dark flecking
on perianth
absent absent or slight absent or slight,
but variable
always present,
few to many
style thickness
just below point of
stigmatic divergence
thickened thickened remains thin remains thin
stigma lobes swollen
short
erect
swollen
long
divergent
slender
short
divergent
slender
long
divergent
anther & pollen color yellow
always
yellow
or brown-lavender
brown-lavender
rarely yellow
brown-lavender
rarely yellow
ploidy diploid tetraploid diploid diploid

Not included: E. americanum subsp. harperi, because the authors questioned its distinctiveness. It's mainly distinguished from E. americanum subsp. americanum by having (1) more strongly-apiculate capsules and (2) stigma lobes that are 'distinctly grooved distally' and variously described as 'recurved' or merely 'divergent'. It is documented from Alabama, Georgia, Mississippi, and southern Tennessee. Geraldine Allen and Kenneth Robertson consider it to be more reliably distinct and single it out in their treatment of the genus for The Flora of North America entry.

Posted on February 21, 2018 21:28 by ddennism ddennism | 3 comments | Leave a comment