Visual Guide to Dichantheliums in Missouri
Click here for a visual overview on the twice-flowering morphology of Dichanthelium.
Click here for information and documentation of Dichanthelium hybrids.
This post serves as an introductory Dichanthelium guide by being a repository of diagnostic photos and characters for each species. This plant genus is the second-largest in Missouri and can appear quite daunting; that being said, due to the broad range of morphologies represented in this group, learning the different entities can be quite easy when you experience them visually (especially in person, of course) with a firm emphasis on habitat. Most species are fairly restricted to very predictable habitats, after all, so you don't need to rely on checking against every other Dichanthelium when you're looking for an ID.
Keys published for groups such as this one are usually technical, relying on spikelet size and ligule length (often in the sub-milimeter range) which can add to the reputation as being "too difficult". However, it is important to note that many keys are written using herbarium material and as such are typically used to identify herbarium specimens, and not necessarily plants in situ. It can be easy to fool yourself into thinking that the morphological characters used in keys are the only visually identifiable features that can be used to tell two species apart, when in reality these characters are usually the ones that are most objective, repeatable, and more apparent in pressed specimens. Thankfully, living plants in situ are bursting with unique character and as such a visual field guide such as this one should hopefully make quick sense. Seeing as how this is an ongoing work in progress, please feel free to add feedback or things you feel need corrected! It should be noted that this guide is not strictly exhaustive for Missouri Dichanthelium; there are a few species that are much more rare, only known from historical collections, or whose existence here is questionable. For the sake of brevity I have omitted those for now (but they may be added in later).
Much credit goes to Justin Thomas whose decades of experience with these grasses has been a key part of my (and many others') journey into understanding them. In particular, the D. acuminatum group for many years was considered one species containing a plethora of obscure entities, but due in part to his research and experience is now well understood to be at least 10 distinct species. See: REVISION OF DICHANTHELIUM SECT. LANUGINOSA (POACEAE)
Spikelet dimensions and botanical illustrations borrowed from Flora of North America.
Dichanthelium you will see very regularly:
- D. boscii - woodlands
- D. clandestinum - sunny riparian generalist
- D. dichotomum - acidic woodlands
- D. lanuginosum - woodlands, grasslands, old fields, disturbed ground
- D. linearifolium - open woodlands and glades
- D. malacophyllum - edges of grasslands, old fields, trails, roads, urban areas
- D. sphaerocarpon - rocky soil of grasslands, woodlands, and glades
- D. scribnerianum - woodlands, grasslands, old fields, disturbed ground
Dichanthelium you will see somewhat regularly:
- D. ashei - dry acidic woodlands
- D. depauperatum - calcareous glades and open woodlands
- D. laxiflorum - acidic woodlands and edges of glades
- D. longiligulatum - periphery of ponded wetlands, banks of streams, wet prairies
- D. polyanthes (Eastern Missouri) - acidic, rocky soils, from glades to edges of streams
- D. scoparium - sunny wet grasslands and old fields
- D. werneri - dry acidic woodlands
Dichanthelium you will see infrequently:
- D. commutatum - dry acidic woodlands
- D. implicatum - dry acidic woodlands, sandstone exposures
- D. latifolium - mesic, shaded riparian edges and forests
- D. microcarpon (Eastern Missouri) - acidic wetland soils
- D. oligosanthes (Southern Missouri) - sandy, shaded woodlands, sandstone glades
- D. perlongum - remnant prairies and glades
- D. ravenellii (Southern Missouri) - dry acidic woodlands
- D. praecocious - exclusive to remnant prairies
- D. villosissimum - acidic woodlands
Dichanthelium you will see uncommonly:
- D. columbianum (Southeastern Missouri) - sand prairies
- D. inflatum (Southern Missouri) - sandy/acidic edges of woodlands
- D. leibergii - remnant prairies and glades
- D. neuranthum (Southwestern Missouri) - remnant prairies
Dichanthelium ashei
Characteristic species of chert and sandstone woodlands, with a low stature, mostly glabrous sheaths, and blue-green hue. The leaves are usually clustered towards the tip of the stem, especially towards the latter half of the season.
Dichanthelium boscii
Very common species of dry forests and woodlands throughout the state. Look for the large spikelets, conspicuously bearded nodes, and lack of basal leaves. It is usually the largest woodland Dichanthelium.
Dichanthelium clandestinum
(Observations for photos 2 and 3)
Very common grass throughout its range where it can be found in wet, open sites, especially along creeks and rivers, usually in abundance where regular disturbance occurs. It is the largest Dichanthelium in the region and is recognized by its wide leaves and stem; large, stiff hairs on the sheath with pustular bases that are nearly sharp to the touch; and habitat.
Dichanthelium columbianum
This is a grass that is endemic to sand and dune communities. As such, it only grows in the few sand prairies that occur in Missouri in the bootheel region. It is a characteristic species for said communities and is unusual for hairy Missouri Dichantheliums by lacking hair along the center of the adaxial leaf surface.
Dichanthelium commutatum var. commutatum
A dry woodland (usually acidic) species that is not very common in Missouri (though it is not rare). Looks very much like D. boscii but lacks long hairs on the nodes, has smaller spikelets, and retains conspicuous basal leaves.
Dichanthelium depauperatum
One of the four Dichantheliums in the area with long, "grass-like" leaves, found in grassland or woodland communities. I most frequently come across it in and around calcareous glades and open woodlands. Famously recognized by its "dunce cap" pointed spikelets. The upper leaf surface is only sparsely hairy and terminates at a very short ligule, a trait it shares with its closest lookalike D. werneri.
Common species of dry open forests, woodlands, and other similarly semi-open and dry sites Thin, short leaves; branches diffusely; tiny spikelets; often with a disproportionately tall vernal inflorescence. Also, the lower nodes are usually retrorsely hairy. Can be confused with D. microcarpon, though that species grows in wetter sites and has reliably smaller spikelets (around 1.6mm, compared to around 2.0mm)
Dichanthelium implicatum
Uncommon member of high quality woodlands and grasslands, usually of acidic substrates. In Missouri it is most likely encountered in cherty woodlands or around sandstone exporures. Morphologically between lanuginosum and villosissimum; long, erect hairs on adaxial leaf surfaces; small spikelets; sheath hairs that are not much longer than sheath width. Very ubiquitously, in the dormant season the autumnal leaves become distinctly recurved (see photo).
Dichanthelium inflatum
This coastal plain species is similar in appearance to the widespread D. sphaerocarpon but is restricted to extreme southern Missouri where it is found on sandy, acidic soils. Its leaves are narrower with mostly parallel margins and has fewer marginal cilia (long hairs) towards the leaf base.
Dichanthelium lanuginosum
A widely distributed and morphologically variably species belonging to the D. acuminatum complex. Usually found in open, grassy places, like woodlands, glades, prairies, sometimes edges of lawns, old fields, etc. It is more common in impacted/disturbed communities but can still be found in high-quality sites, especially acidic woodlands. Check for small spikelets, hairy leaves, and sheath hairs that are equal or less than the sheath width (rarely slightly longer).
The synonym for this species when it is retained within the concept of D. acuminatum is D. acuminatum var. fasciculatum. Don't be surprised if the key you're using doesn't use D. lanuginosum, it is still widely considered to be a variety.
There is a common entity found along calcareous rocky banks of streams and creeks that technically falls under our concept of D. lanuginosum, and it looks like this. It is very similar to D. lanuginosum but with glabrous leaves. It is not certain whether this is separate species or merely a form of D. lanuginosum.
See here for a comparison with D. malacophyllum.
Dichanthelium latifolium
A less common species of mesic forests and riparian corridors of at least some remnant quality. Can be a dead-ringer for clandestinum but is easily differentiated by sheaths that are completely glabrous minus a line of hairs along the margins, along with being overall slightly smaller in stature. I find that the leaves clasp much more strongly, as well.
Dichanthelium laxiflorum
One of the more unique and easily recognizable in the genus and is commonly encountered in woodlands across the Missouri Ozarks. Owing to the name, it is quite prostrate and "floppy"; tufts sprouting long lime-green hairy leaves with marginal cilia halfway up the length. Usually grows in colonies.
Dichanthelium leibergii
A distinct grass of high quality prairie and glade remnants that is rare in Missouri. Large for a grassland Dichanthelium, it is evenly covered in short, erect hairs with pustular bases and has a "fuzzy" appearance. Also look for spikelets with long hairs and a very short ligule.
Dichanthelium linearifolium
One of the four Dichantheliums in the area with long, "grass-like" leaves, found in grassland or woodland communities (especially glades). Of the four it is typically the hairiest, with conspicuous, messy, long sheath hairs of varying lengths. The upper leaf surface is also consistently short hairy (making the ligule difficult to isolate visually), a character that separates it from D. depauperatum and D. werneri. Furthermore, it is often the tallest and leggiest grass-like Dichanthelium. Individuals on acidic glades, for example, can attain quite the stature.
Dichanthelium longiligulatum
A somewhat cryptic, short-leaved species that favors acidic soils near wetlands, like natural ponds or creeks. Owing to its name it has a very long, distinct ligule. Also look for very small spikelets (around 1.0mm), few to none marginal cilia, and leaves that are consistently short. By the autumnal phase it usually takes a pom-pom like appearance with orderly fascicles of leaves occurring along the stem. This grass is increasing in distribution; I find it even around pasture ponds.
Dichanthelium malacophyllum
A Dichanthelium that can be readily ID'd with just a single touch of the thin leaves as this species is covered in very short, soft hairs that feel like felt. It is somewhat common in the southern half of the state, though it is probably overlooked. Usually found in dry, disturbed sites like old fields, edges of lawns, and edges of glades. Tends to grow a little taller and leafier than other Dichantheliums with similar leaf proportions. Sometimes D. lanuginosum can appear similar to malacophyllum, but its spikelets are nearly half as long, appearing distinctly smaller (approx. 1.5mm and 3.0mm, respectively).
See here for a comparison with D. lanuginosum.
Dichanthelium microcarpon
A grass that is much more common further east but is more restricted in Missouri as it prefers acidic, wet, rocky substrates. Here it is most commonly found in the St. Francois Mountains region along creeks, seeps, and streams, less commonly around sinkhole ponds and low wet areas in prairies. The stems become highly branched through the season and bear small spikelets and nodes with distinctly retrorse hairs.
Dichanthelium neuranthum
A coastal plain species that is rare in Missouri, found in just a handful of prairie remnants in the southwestern and western portions of the state. Where it does occur here, though, it is often in abundance and is probably overlooked. The leaves are as thin or even thinner than the "grass-like" species but shorter and are distributed along the stem and not growing basally; the plant is usually quite glabrous.
Dichanthelium oligosanthes
Uncommon in Missouri, known from scattered locations in the southern and eastern Ozarks (though it is probably overlooked). Appears like the very common scribnerianum but with narrower, longer leaves, a longer ligule, and bigger spikelets. The leaves are often widely spreading, compared to scribnerianum's more ascending leaves. Look for this species in sandy soils, like sand prairies, sandstone glades/woodlands/etc.
Dichanthelium perlongum
(Observation to photo 2)
The most uncommon of the four "grass-like" species, being found only in high quality prairies, glades, and sometimes open woodlands. Look for large (<3.0mm) rounded spikelets born sparsely on the inflorescence and abaxial (lower) leaf surfaces with dense, orderly, ascending hairs.
Dichanthelium polyanthes
Another species that is much more common further east and is found near the edge of its range in eastern Missouri where it is often encountered in woodlands of varying substrates (though usually acidic). It is a tall Dichanthelium with wide leaves and large, conspicuous inflorescences that are taller than wide and adorned with small, round spikelets. The big brother of D. sphaerocarpon, see here for a comparison between the two.
Dichanthelium praecocious
A relatively sensitive species of high quality tallgrass prairie remnants than can become locally extirpated given enough disturbance. It looks very similar to lanuginosum, who it often co-occurs with, but faithfully bears sheath hairs that are much longer than the sheath width. Towards the end of the summer the leaf and sheath hairs become scraggly, stiff, and disheveled, feeling very different from other grassland Dichantheliums. Also, the leaves (especially towards the later end of the season) tend to be strongly ascending, further separating it from D. lanuginosum's more spreading leaves.
Dichanthelium ravenellii
A slightly uncommon grass of high quality acidic woodlands in the southern third of the state. It is unusual in appearance, with long, curled-upward leaves clustered towards the tip of the stem (appearing fascicled) and very large, hairy spikelets. The upper leaf surface is glabrous, the lower is hairy.
Dichanthelium scoparium
A fuzzy Dichanthelium found in open, often wet ground in southern Missouri. It's a characteristic species of prairie swales but can be found in a variety of other habitats. It usually grows quite tall with short autumnal branches. The numerous felty, arching leaves are distinctive, but the best character is the stem pubescence that increases in density above each node, followed by a "bald patch" beneath the node.
Dichanthelium sphaerocarpon
One of the more common species in the state, occurring in a variety of dry habitats, usually on rocky soil. It is often smaller than most others in the group, and is known for the orbicular spikelets for which it is named. The sheaths are glabrous; the ligule is absent or minuscule; and the leaves are thick, erect, and with prominent marginal cilia towards the base. See here for a comparison with *D. polyanthes.
Dichanthelium scribernianum
Very common, weedy species found throughout the state. It is most commonly found in overgrown lawns, fields, roadsides, etc., though it is regularly found in more intact communities like prairies, glades, and openings of woodlands. The leaves are glabrous on the upper surface and often "boat shaped" as the tips curve upwards, the sheaths are stiff-hairy with pustular bases, and the spikelets are large (in the 3.0mm range).
Dichanthelium villosissimum
Characteristic species of high quality chert/sandstone woodlands in the southern third of Missouri. It puts the villous in villosissimum! It is well adorned with long, wiry hairs that are exceedingly longer than the sheaths are wide. It is often prostrate and messy in posture later in the growing season. Most similar to D. praecocious but their habitats almost never overlap.
Dichanthelium werneri
One of the four Dichantheliums in the area with long, "grass-like" leaves and a characteristic species of acidic woodlands. Very similar in appearance to depauperatum, but with more blunt spikelets (not dunce-cap shaped) and often with slightly revolute leaf margins that, when added with the slightly recessed central vein, lead to a subtle "m" shape to the leaf cross-section.
Comments
What source are you using for: "This plant genus is the second-largest in North America"? I know JT put this in one his presentation slides (but specifying eastern North America), but I have a hard time believing the notion. Astragalus, Carex, Erigeron, Eriogonum, Euphorbia, Lupinus, Quercus, Penstemon, Solidago, Symphyotrichum, and probably a couple of others that I'm not rememebering surely are just as if not more diverse than Dichanehtelium. Now, if things like Dichanthelium acuminatum are going to be split into a dozen taxa (and if that increase is applied to every widely accepted species), then possibly. But I hesitate to accept such drastic taxonomic changes without concerete morphometric/morphological statistic and/or molecular phylogenetic data to back that up (which I don't think JT directly does himself). I resist such because a new taxonomic treatment (self-published by Guy Nesom for Heterotheca with no morphometric/phylogenetic data) was converted over for Heterotheca (of either 45 or 75 taxa depending on whether you follow Semple or Nesom), and it has caused widespread confusion and chaos not just on iNaturalist but also in herbarium collections.
Fantastic! Thank you so much for putting this together. I have certainly passed up plenty of opportunities to make a Dichanthelium observation, thinking that I'd never get beyond genus. The curated photos and habitat descriptions are/will be very helpful. I look forward to using this.
@marisaszubryt thank you for catching that! It's a typo, I meant second largest in Missouri!
Excellent resource—thank you!
@ciafre just informed me you’d created this outstanding guide, major kudos!
Just wanted to add--my experience with leibergii is that in the autumnal phase, when other similarly-statured grassland Dichantheliums have become fascicled and tufty, autumnal leibergii culms are sparsely branched and not much fascicled, with leaves that are evenly and rather widely spaced in comparison... very distinctive and elegant late-season gestalt.
Wow! Lovely! Thank you!
Excellent guide! I had one question/note. Is the Missouri Dichanthelium neuranthum actually Dichanthelium ovinum? A lot of the specimens I saw in Northwest Arkansas in May were called that.
@wildlander Thanks Jared!
In Missouri (and Arkansas), D. neuranthum and D. ovinum are treated as separate entities (see Wipff and Shaw 2018). True neuranthum is indeed in southwestern MO, however ovinum is quite rare. I believe it's only been observed once, first reported by JT (of course!). There is a mild floristic tension zone right around the AR-MO border and many species found regularly close to the border are absent on the other side.
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