Vascular Plants of North Carolina
Account for Variable Witchgrass - Dichanthelium commutatum   (J.A. Schultes) Gould
Members of Dichanthelium with account distribution info or public map:
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Section 5 » Order Cyperales » Family Poaceae
Author(J.A. Schultes) Gould
DistributionThroughout the state, including the Outer Banks and barrier islands.

ME to MI and MO, south to FL and TX; Mex.
AbundanceEssentially common throughout the state.
HabitatDry to mesic or moist woodlands and forests of many kinds, including open and rocky to shady and moist, trailsides, etc.
PhenologyFlowering and fruiting May-October.
IdentificationTogether, D. commutatum var. ashei and var. commutatum are among our most often encountered witchgrasses. Var. ashei has narrower and shorter leaves, plus very short-hairy (puberulent) stems (vs. glabrous). Leaves of var. commutatum may be broad enough to recall D. boscii and D. latifolium; see them for separation.
Taxonomic CommentsTwo varieties occur in the state, both essentially statewide -- var. ashei and var. commutatum.

A note about Dichanthelium: This genus is not impossible to identify to species! But it takes applied effort over a period of time in order to learn the various species and what their morphological limits are. We strongly recommend that you read the introduction to the treatment in Weakley (2018), written by Richard LeBlond. LeBlond has made order out of near chaos, and his keys work very well for our plants. Most Dichanthelium taxa ("Dichs") do not grow everywhere indiscrimminately, but prefer certain well-defined habitats. Note that most species produce flowers/fruits twice a year -- a vernal period and an autumnal period -- and that measurements of spikelets and achenes are taken from vernal plants. Some species also have a third, or summer, period. In the vernal period there is a single inflorescence at the tip of the stem. In the autumnal period, plants produce elongate branches with bunched (congested) leaves and so look quite different from vernal plants. Inflorescences are produced in leaf axils as well as at the tips of branches. NOTE: Older texts had these species essentially all within the very large genus Panicum. "Dich" species are typically named as "Witchgrass" and Panicum species named as "Panicgrass".
Other Common Name(s)Variable Panicgrass
State RankS5
Global RankG5
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