October 08, 2019

Goldenrod Galls

I can't find a single resource online with all these gall-formers in one place, so here are my notes. This is not an exhaustive list, but I'm striving to include as many as I can. Right now, many observations on iNaturalist of Rhopalomyia solidaginis are probably actually other bud-galling species, because I think people are unaware of the great diversity of gall-midges and other gall-formers. However, many of those observations don't really match any of these known ones, either. I think there are 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/

() = 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-forming insect host gall gall description sources
Procecidochares atra S. altissima,
S. gigantea,
S. rugosa,
(Erigeron canadensis),
(Aster sp.)
bud Spring Generation: Large stem galls in base of host containing several larvae.

Summer Generation: Lateral (sometimes also terminal?) bud galls that look like artichokes initially, and eventually open as fly matures. Gall chamber is large and not sealed; somewhat open at the distal end. Each gall has only one larva, unlike in spring generation. Probably has many other hosts, including some outside Solidago.
wikipedia, iNat obs, bugguide, Philips and Smith (1998)
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 E. elsa (Phillips 1923, Novak & Foote (1980)), which modern sources synonymize with this taxon. 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 up and is mostly above-ground at maturity. Like that of E. comma, galls resemble peanuts somewhat. Are the two host-species really hosting the same species? bugguide, Arthr. Fl.
Eurosta floridensis S. fistulosa rhizome Similar to E. comma. Arth. Fl.
Eurosta lateralis S. chapmanii stem Similar to E. solidaginis. Only known from Brevard Co., FL, at least recently Arth. Fl.
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 Bucknell solidago gall website, Moffatt et al. (2019) Stoltzfus (1989)
Eutreta hesperis Solidago root source differentiates between rhizome and root galls Stoltzfus (1974)
Eutreta noveboracensis S. altissima,
(S. rugosa)
rhizome bores through rhizomes, (sometimes?) making galls bugguide, Stoltzfus (1974)
Gnorimoschema gallaesolidaginis S. altissima,
S. canadensis
stem ellipsoid stem galls with a characteristic white exit bung Miller (1963)
Epliblema scudderiana S. altissima stem narrowly cylindrical-ellipsoid stem galls. But see also Lasioptera Miller (1963)
Epiblema desertana E. graminifolia stem very narrow stem galls. But see also Lasioptera(?) Miller (1963)
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 soil line, wider and harder than normal buds, single chamber lined with white mycelium. Or, slightly later, bud galls at the tip of longer sprouts that still appear stunted and thickened.

Summer Generation (S. juncea, S. erecta, S. uliginosa and NOT S. altissima): Much more conspicuous apical rosette bud galls, lined with mycelium, 15-30 rosette-units, forming a spherical single structure at the shoot apex. Occasionally found on lateral buds on S. uliginosa, rarely found there on other species.
Dorchin et al. (2015)
Asphondylia pseudorosa E. graminifolia bud Vegetative bud galls usually at apex, but also on lateral buds; Rigid base with dramatically wider leaves than normal, giving the whole structure the appearance of a rosebud. The internal chamber is lined with a white mycelium; inflorescence bud galls are also formed, later in the season. They are difficult to distinguish from normal inflorescence buds. 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. 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 very young) to make a single chamber lined with white mycelium. Unlike in A. solidaginis, the galled leaves are often located nearer the plant apex, giving rise to a gradient of snap to bud galls.

Mid-Late Summer: Bud galls (only S. rugosa) on apical buds only, with a single, conical chamber in the middle that is lined with white mycelium. These galls are smaller and flatter than those formed by R. solidaginis, and are composed of fewer leaves.
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 when very young) to make a single chamber lined with white mycelium.

Mid-Late Summer: Bud galls (only S. altissima) on apical or axillary buds of S. altissima (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 visible without dissection, and the gall walls are lined with thick white mycelia. The rosettes are also smaller in size, and flatter (not tufted).
Dorchin et al. (2015)
Asphondylia sp. (S. bicolor galler) S. bicolor bud S. monacha-like galls (and insects) that are distinct from A. monacha according to molecular phylogeny. Could be the same species as A. sp. "S. sempervirens galler". One S. uliginosa rosette gall adult also sorted into this clade, while others sorted into S. monacha. Dorchin et al. (2015)
Asphondylia sp. (S. sempervirens galler) S. sempervirens bud S. monacha-like galls (and insects) that are distinct from A. monacha according to molecular phylogeny. 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 S. monacha. Dorchin et al. (2015)
Asphondylia sp. (S. uliginosa galler) S. uliginosa bud See comments for A. "sempervirens galler" and A. "bicolor galler". Distinct, at least, from A. monacha, though that species also forms rosette bud galls on S. uliginosa Dorchin et al. (2015)
unknown, but Asphondylia suspected S. nemoralis leaf snap Leaf-snap galls observed rarely, but insect unknown Dorchin et al. (2015)
unknown, but Asphondylia suspected S. tortifolia* bud A. rosulata-like galls in October, but insect unknown Dorchin et al. (2015)
unknown, but Asphondylia suspected S. patula bud Aggregated bud galls like those of A. monacha known, but insect unknown. Could be A. monacha, or another gall-maker. Dorchin et al. (2015)
unknown, but Asphondylia suspected S. odora bud Aggregated bud galls like those of A. monacha known, but insects unknown. Could be A. monacha, or another insect. A. Diamond has observed galls in Alabama on S. odora that closely resemble R. solidaginis galls on S. altissima. These may or may not be the same galls Dorchin (2015) is referring to. Dorchin et al. (2015), iNat observation
Dasineura carbonaria E. graminifolia bud Shoot tip bud galls, loose, with twisted and/or inrolled leaves Dorchin et al. (2007)
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 Dorchin et al. (2007)
Rhopalomyia bulbula S. juncea bud Only a spring generation is known, but the insect is presumably multivoltine;
Spring Generation: Clustered on rhizomes, at bases of spring shoots. Gall resembles a bud, with acute apex and base. Surface smooth and white, green 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 small leaves give the overall gall complex a flat-topped appearance.
Dorchin et al. (2009)
Rhopalomyia anthophila S. altissima capitulum Capitulum galls among the inflorescence. Cylindrical, or like a truncated cone. Fuzzy and whitish. Inner chamber conical with thin walls. Dorchin et al. (2009)
Rhopalomyia lobata E. graminifolia bud Multi-chambered galls in apical and lateral buds. Start as 1 cm globular swellings in shoot tips or clusters 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. Dorchin et al. (2009)
Rhopalomyia hirtipes S. juncea bud Fleshy bud galls at shoot apex, but shoots often arrested when very short. Gall initially has a tapered tip, but this disappears with growth, the whole gall becoming ovoid and reminiscent of a potato. Spongy and usually multi-chambered. Dorchin et al. (2009)
Rhopalomyia solidaginis S. altissima,
S. canadensis,
S. rugosa,
((S. odora))
bud Spring Generation: Inconspicuous, shoot tip bud galls, often stunting the shoot.

Summer generation: each of multiple (2-5) chambers is surrounded by a group of very short and narrow leaves, which in turn are surrounded by longer and wider leaves to form a distinct subunit within the gall. The whole complex makes a conspicuous rosette.
A. Diamond has observed similar galls on S. odora; I'm not sure if these are the galls that Dorchin (2015) refers to, and suspects an Asphondylia of making. At least superficially, they resemble R. solidaginis galls moreso than Asphondylia monacha galls.
Dorchin et al. (2009)
Rhopalomyia thompsoni S. altissima bud Spring Generation: Solitary or clustered, bulbous, fleshy masses with 1-8 chambers each. Start on rhizomes but become apparent above ground by emergence 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.
Dorchin et al. (2009)
Rhopalomyia guttata S. bicolor capitulum Among normal-looking inflorescence pedicels among other capitula. 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. Unlike R. anthophila galls, these retain pedicels. Dorchin et al. (2009)
Rhopalomyia racemicola S. altissima,
(S. fistulosa)
capitulum Green, bristly, onion-shaped capitulum galls, sometimes in aggregations. Galls on S. fistulosa tenatively identified as this species. 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. Dorchin et al. (2009)
Rhopalomyia pedicellata E. graminifolia variable Off of stems, leaves, 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. 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 Dorchin et al. (2009)
Rhopalomyia clarkei S. rugosa,
S. altissima
vascular outgrowth 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. Dorchin et al. (2009)
Rhopalomyia gina S. juncea vascular outgrowth Like R. clarkei galls, but usually on upper side of leaf and with a corresponding scar or little tail on other side. Hairless. Dorchin et al. (2009)
Rhopalomyia inquisitor S. gigantea vascular outgrowth Originally described as an inquiline in R. capitata galls, but this could not be replicated. R. clarkei-like galls (except smooth) on S. gigantea, though, particularly from R. clarkei-like galls within Dasineura follicularis galls on S. gigantea, might be the real galls of this species. Maybe Felt confused D. follicularis galls with R. capitata, and then found these "inquilines" that way? However, Dorchin et al. (2009) were unable to rear any adults from these R. clarkei-like galls, so the galls of R. inquisitor remain unknown. Dorchin et al. (2009)
Rhopalomyia cruziana (S. spathulata),
(S. velutina)
capitulum? From an unknown Solidago from Santa Cruz mountains in California. Gall probably from a capitulum gall, based on adult insect similarities, but gall itself unknown. Dorchin et al. (2009)
Asteromyia euthamiae Euthamia leaf spot Black spots on leaves Stiremann et al. (2010)
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. Stiremann et al. (2010)
Asteromyia modesta Solidago,
Erigeron,
Conyza**,
Grindelia,
Symphyotrichum
leaf spot Leaf blisters. Possibly polyphyletic, with two distinct clades, one of which is itself polyphyletic with the recognition of A. tumifica. Both clades include some individuals that make galls on Solidago. Stiremann et al. (2010)
Asteromyia carbonifera Solidago leaf spot Black spots on leaves Stiremann et al. (2010)
Lasioptera solidaginis Solidago stem Irregular, elongate stem-swelling galls. Makes a small exit hole on the side of the gall. But see also Epliblema moths. bugguide
Schizomyia racemicola Solidago capitulum Greenish-purplish onion-shaped capitulum galls alongside normal capitula in the inflorescence. Gall exterior is smooth. Gall-maker larva exits gall as a larva and pupates elsewhere. bugguide

Trupanea might infest goldenrod flower-heads, but do they form galls?

*observed in Maryland (??)
**I think this Conyza species is probably C. canadensis, which is back in Erigeron now.

References
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):
Dorchin et al. (2009):
Dorchin et al. (2015):
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
Stiremann (2010):
Stoltzfus (1989): https://scholarworks.uni.edu/cgi/viewcontent.cgi?article=1587&context=jias

Posted on October 08, 2019 06:53 by ddennism ddennism | 7 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 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
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