E-Flora BC: Electronic Atlas of the Flora of British Columbia

Panicum dichotomiflorum Michx.
smooth witchgrass (fall panicgrass)
Poaceae (Grass family)

Introduction to Vascular Plants

© Frank Lomer  Email the photographer   (Photo ID #29153)

E-Flora BC Static Map
Distribution of Panicum dichotomiflorum
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Panicum dichotomiflorum ssp. dichotomiflorum

Species Information

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Annual grass from fibrous roots, usually branching from the base; stems decumbent to erect, up to 100 cm tall/long.
Sheaths open, usually smooth, but the throats sometimes with a few hairs up to 3 mm long, the collars smooth; basal leaves similar to the stem leaves, the blades somewhat rough but otherwise smooth, 4-12 mm wide; ligules 2-3 mm long, the lower third membranous.
Inflorescence a panicle, 15-30 cm long, the branches ascending; spikelets 2-flowered, about 2.5 mm long, the lower florets sterile, the upper ones always fertile; lower glumes egg-shaped, with rounded tips, about 1/4 the length of the spikelets, 0.5-1 mm long, the upper ones smooth, lightly 9-nerved, sharp-pointed; sterile lemmas smooth, lightly 9-nerved, sharp-pointed, with translucent paleas 1-1.5 mm long; fertile lemmas much-hardened and faintly-nerved; lodicules about 0.5 mm long, semi-tubular; anthers about 1.2 mm long.

Source: The Illustrated Flora of British Columbia

USDA Species Characteristics

Flower Colour:
Blooming Period:
Fruit/Seed characteristics:
Colour: Yellow
Present from Summer to Fall
Source:  The USDA

Habitat / Range

Moist railway embankments and waste areas in the lowland zone; rare in SW BC (lower Fraser Valley); introduced from E and central N America.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Panicum dichotomiflorum

The table below shows the species-specific information calculated from
original data (BEC database) provided by the BC Ministry of Forests and Range.
(Updated August, 2013)

Site Information
Value / Class




Elevation (metres) 537 537 537
Slope Gradient (%) 4 4 4
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
167 166 167
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
5 5 5
Modal Nutrient Regime
Number of field plots
 species was recorded in:
Modal BEC Zone Class
All BEC Zones (# of stations/zone) species was recorded in: BG(1)


The climate type for this species, as reported in the: "British Columbia plant species codes and selected attributes. Version 6 Database" (Meidinger et al. 2008), is not evaluated, unknown or variable.

Taxonomic and Nomenclatural Links

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General References