Plants annual or perennial; cespitose, sometimes rhizomatous. Culms 10-180 cm, glabrous or hispidulous; nodes 2-5, glabrous. Sheaths open, smooth or scabrous; auricles absent; ligules hyaline, glabrous, obtuse to acute; blades flat, smooth or scabrous over the veins. Inflorescences open panicles; branches drooping to ascending, smooth or scabrous. Spikelets dorsally compressed, with 1 floret; rachillas not prolonged beyond the fertile floret; disarticulation above the glumes. Glumes equal, equaling or exceeding the lemmas, membranous, smooth or scabrous; calluses blunt, glabrous; lemmas coriaceous, glabrous, lustrous, margins involute, obscurely 5-veined; paleas similar to the lemmas and partly enfolded by them; lodicules 2, free, glabrous, toothed or not toothed; anthers 3. Caryopses glabrous; hila 1/5 to nearly 1/2 the length of the caryopses. x = 4, 5, 7, 9. Name from an old Latin word for millet, an appellation which is associated with species in several different genera.

Milium is a circumtemperate genus of four species. All the species grow in mesic to dry mixed woods and dry open habitats. Milium effusum is native to the Flora region; M. vernale has become established here.

1.   Milium effusum L.
Wood Millet, Millet Diffus

Plants perennial; rhizomatous. Culms 55-140 cm, erect from decumbent bases, glabrous; nodes 3-5. Sheaths glabrous; ligules 3-9 mm, obtuse-erose; blades 5-26 cm long, 8-17 mm wide, flat, glabrous, equably distributed on the culms. Panicles 10-27 cm; branches 1-9 cm, in pairs or fascicles, flexuous, spreading or drooping, scabrous, the spikelets mainly near the ends. Glumes 2.5-5 mm, scabrous, 3-veined, acute to acuminate; lemmas 2.3-3 mm, acute; anthers 1.5-2 mm. 2n = 14, 28.

Milium effusum is widespread in temperate to subarctic regions in the Northern Hemisphere. North American plants belong to M. effusum var. cisatlanticum Fernald, an elegant native grass that grows in woodlands in eastern North America. It differs from M. effusum L. var. effusum, which grows from Europe to Asia and Japan, in having 2-3 panicle branches at most nodes and spikelets 2.5-5 mm long, rather than 4-5 panicle branches at most nodes and spikelets about 3 mm long. A cultivar of M. effusum, 'Aureum', is grown for its yellowish leaves. 2010: Haines raised M. effusum var. cisatlanticum to subspecific rank as Milium effusum subsp. cisatlanticum (Fernald) A. Haines.