Proso millet Panicum miliaceum L., [PANMI, panic millet, Proso, Wild proso millet, Millet, Broom-corn millet] Annual, reproducing only by seed. Stems stout, up to 1 m (40 in.) or more high, smooth or somewhat hairy for several cm below each node, especially where not enclosed within the leaf sheath; leaf sheaths densely hairy, the hairs somewhat harsh and standing more or less perpendicular to the surface; leaf sheaths split, their margins membranous, overlapping just above each node but becoming separate upwards nearer the leaf blade; leaves smooth to sparsely hairy, elongate, to 30cm (12 in.) or longer, and 5 - 25 mm (1/5 - 1 in.) wide, widest just above the rounded base and tapering towards the tip; ligule a band of hairs 2 - 5 mm (1/12 - 1.5 in.) long, the bases of the hairs united and more or less membranous; no auricles; panicle either dense and arching or nodding to one side (usually associated with cream-, orange-, or reddish-seeded forms) or erect and loose or open (usually associated with black-seeded forms), 8 - 30cm (3-1/5 - 12 in.) long; spikelets ovoid, 4 - 5.5 mm (1/6 - 1/4 in.) long and 1/2 to 2/3 as wide; seeds 3-3.5 mm (1/9 - 1/7 in.) long by about 1.6 - 2.0 mm (1/15-1/12 in.) wide, hard and usually shiny, varying in colour from white through shades of yellow, orange and brown to black, the darker coloured seeds with 5 parallel beige veins. Flowers from July to September.
Proso millet was introduced from Europe. Some forms are cultivated for bird seed and some of these along with other wild forms are major weeds of grain-fields in parts of southern Ontario.
It is distinguished from the very similar Witch grass by its much larger seeds that may vary in colour from white through cream, orange, reddish or brownish-green to black, and by the arching or nodding panicle in some forms (the erect, open-panicled forms usually being larger, coarser and having fewer seeds than Witch grass); and it is distinguished from Fall panicum by its hairy leaf sheaths and its larger spikelets. Seedlings of Proso millet can be distinguished from those of Witch grass only by the size, shape and colour of the mother seed clinging to the primary root.
(Source: Ontario Ministry of Agriculture and Food, Publication 505, Ontario Weeds)
