LARGE CRABGRASS, Digitaria sanguinalis
(L.) Scop. 1, plant; 2, section of spike showing spikelets;
3, seed; 4, distribution. Annual, reproducing by seed.
Stems stout, smooth, up to 3 feet long; when prostrate, rooting
at the joints. Leaf blades usually at least somewhat hairy, 1/4
to 1/3 inch (6 to 8 mm) wide; leaf sheaths, especially the lower ones,
densely long-hairy. Inflorescence has 3 to 10 segments, in whorls
at top of stem. Seeds 3/32 inch (2.4 mm) long, alternate on the
branches of the inflorescence. Found in lawns, gardens, and fields.
The most troublesome lawn weed in southern part of region. Starts late,
when ground is quite warm; grows well under dry, hot conditions; flowers
August-September. Also commonly known as hairy crabgrass.
SMOOTH CRABGRASS, Digitaria ischaemum (Schreb.)
Muhl. 5, distribution. Similar to above but not so coarse or tall,
without hairs, more purplish or bluish. Found in same places as
large crabgrass, but most commonly in lawns.