The plant seeds in hot countries but not in cool, temperate regions; spreading chiefly by coarse, hard rootstocks. Introduced.
=Small Crab-Grass.= _Digitaria humifusa_ Pers. _Panicum lineare_ Kroach. _Syntherisma linearis_ (Kroch.) Nash. Spikelets in the rough, before severe rubbing, ovoid or oblong, flattened, 2 mm. long, first glume minute, second and third as long as the spikelet, soft with very short hairs, one of them 3-nerved, the other 5-nerved; floret after severe rubbing, brown to black, smooth, floral glume of the rounded side curving over the edges below covering with their edges about two-thirds of the palea. Introduced from Europe; becoming troublesome on thin lawns.
=Large Crab-Grass. Finger Grass.= _Digitaria sanguinalis_ (L.) Scop. _Panicum sanguinale L. Syntherisma_ (L.) Nash. Spikelets before severe rubbing, oblong, acute, 2.5-3.5 mm. long, first glume on flattened side minute, second on rounded side about half as long as the spikelet, pubescent or nearly smooth, third glume more or less pubescent, 5-7-nerved; floret, after severe rubbing, smooth, edges of floral glume thin. Introduced from Europe. Roots very tough and coming from the lower joints.
=Barnyard Grass.= _Echinochloa Crus-galli_ (L.) Beauv. _Panicum Crus-galli_ L. Florets oval, white, yellowish gray or brown, 2.4-3 mm. long, plano-convex, glume on the convex side, highly polished, three obscure longitudinal nerves. Native of this country.
=Yard-Grass. Wire-Grass.= _Eleusine Indica_ (L.) Gaertn. Florets light lead color or brown before threshing or much rubbing; grain dark, reddish brown, 1.2-1.4 mm., ovoid with the base abruptly pointed, 3 sided, the corners rounded, a vertical groove along one side; seen from the back with the groove side down and base toward the observer, starting from an oval spot near the base, 10-15 ridges on each side, extend downward and forward. Introduced from some warmer region of the Old World.
=Stink-Grass.= _Eragrostis megastachya_ (Koeler) Link. _Eragrostis major_ Host. Grain orange red or wine color .4-.6 mm. long. Broad oval to nearly circular, very slightly flattened, extremities slightly pointed, embryo within one edge near the base, a fine network of dark lines evident under a good lens. Introduced from Europe.