Coix lachryma-jobi, L.
This is a tall monoecious leafy annual (rarely perennial) grass with stout, smooth, polished, freely branching stems rooting at the lower nodes and varying in length from 3 to 5 feet or more.
The leaf-sheath is long, usually smooth but occasionally with scattered tubercle-based hairs. The ligule is a narrow membrane. The nodes are glabrous.
The leaf-blade is long, flat, narrow or broad, acuminate, cordate at base, with a stout midrib and many slender veins on both sides, usually glabrous on both sides though occasionally with scattered hairs, and with spinulosely serrate margins, varying from 4 to 18 inches in length and 1/3 to 2 inches in breadth.
The inflorescence consists of nodding or drooping spiciform racemes, 1 to 1-1/2 inches long, terminating the branches. The racemes consist of many male spikelets with one (rarely two) female spikelets at the base; the rachis is stout above, and the part within the bract enclosing the female spikelet is slender.
The male spikelets are imbricating, 2 or 3 at a node of the rachis, one sessile and one or two pedicelled, dorsally compressed, articulate at the base and persistent, very variable in size, 3/8 to 3/4 inch. There are four glumes in the spikelet. The first glume is oblong-lanceolate, chartaceous, 3/5 inch long, acute, many-nerved, concave with inflexed margins bearing narrow green many-veined wings. The second glume is similar to the first, but thinner and without the wings, 5- to 9- or rarely 11-nerved. The third glume is oblong-lanceolate, hyaline, faintly 3- to 5-nerved, paleate and with three stamens. The fourth glume is similar to the third, paleate with or without stamens.
Fig. 126.—Coix Lachryma-Jobi.
1. Inflorescence; 2. the female spikelet; 3. male spikelets; 4, 5, 6 and 8. the first, second, third and the fourth glume, respectively, of a male spikelet; 7 and 9. palea of the third and the fourth glumes, respectively.]