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| Stem and leaf-base characteristics of a typical grass. Ontario - Ministry of Agriculture |
Fall panicum (Panicum dichotomiflorum) has a zigzag appearance as the buds turn out at the nodes. The zigzag growth pattern is one of the primary identifying characteristics. It has a very rounded stem, grows to 7’ and there is a purple tinge to its inflorescence.
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| Fall panicum. A. Plant. B. Leaf-base. C. Panicle. D. 2
spikelets. Ontario - Ministry of Agriculture |
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| Strand Memorial Herbarium |
Panicle, the name for the type of seed head produced by this grass, gives fall panicum both its common and scientific names. Because its seeds do not mature until late summer or autumn, the grass is commonly called fall panicum. Dichotomiflorum is a Latin word that refers to a distinguishing feature of fall panicum: the individual flowers (florets) are arranged in pairs.
Other common names for fall panicum include fall panicgrass, spreading witchgrass, spreading panicgrass, spreading panicum, sprouting crabgrass, and kneegrass. The last name is an apt description of the nodes, which are swollen, slightly bent, and very shiny.
Sometimes fall panicum is mistaken for johnsongrass (Sorghum halepense) or barnyardgrass (Echinochloa crus-galli). However, johnsongrass has a membranous ligule unlike that of fall panicum and johnson grass seedlings also do not have hairs on the lower leaf surface like those of fall panicum. Barnyardgrass does not have a ligule at all and barnyardgrass seedlings might only have hairs near the leaf base.
Additional Information
Fall Panicum - Penn State University
Panicum Images - Strand Memorial Herbarium
Identifying Grass Seedlings - IPM University of Missouri
Botanical Dictionary - University of North Carolina - Chapel Hill
