Fig. 130.—Ischæmum aristatum.
1. A portion of the raceme showing the joints, sessile and pedicelled spikelets; 2, 3, 4 and 6. the first, second, third and the fourth glume, respectively, of the sessile spikelet; 5 and 7. palea of the third and the fourth glumes, respectively; 8. ovary, stamens and lodicules; 9. first glume of the pedicelled spikelet.
The spikelets are 1/6 to 1/3 inch long, the sessile and the pedicelled closely pressed together, glabrous or hairy; the callus of the sessile spikelet broad and thick, with or without hairs. The sessile spikelet is awned and consists of four glumes. The first glume is 1/5 inch long or less, oblong or linear-oblong, cartilaginous below the middle, with two to four (or rarely up to six) marginal nodules on each edge, sometimes these are connected by shallow ridges, thinner above the middle, with green anastomosing veins, tip obtuse or 2-toothed, and margins narrowly incurved. The second glume is chartaceous, lanceolate, acuminate, 1-nerved and with a smooth rounded keel. The third glume is ovate-lanceolate, membranous, 1-nerved, acuminate, male or bisexual with an oblong palea. The fourth glume is cleft to or below the middle into lanceolate acute lobes, with a brownish red awn 1/2 inch or more long at the sinus twisted at the lower portion and straight above, paleate, usually female; palea is linear oblong. The pedicelled spikelet is as long as the sessile, inarticulate on the very thick, short pedicel which is densely or sparsely hairy at the base. The first glume is scimitar-shaped, coriaceous, acute, with a somewhat semi-circular wing. The other glumes are as in sessile spikelets, but the fourth glume has no awn and may have a mucro.
This grass is a variable one. There is much variation in the breadth of the leaves and in the markings and hairiness of the spikelets. The spikelets may be glabrous or hairy and the marking in the first glume of the sessile spikelets varies in the matter of marginal nodules—it may have mere shallow notches or deep well-formed nodules and there may be transverse ridges or they may be absent. This grass is abundant on the West Coast and rare in the East Coast.
Distribution.—Throughout the plains and lower hills of India and Ceylon.
Fig. 131.—Ischæmum aristatum.
A. A portion of the raceme showing the joints; B. a sessile and a pedicelled spikelet. 1, 2, 3 and 6. the first, second, third and the fourth glume, respectively; 4 and 5. palea of the third and the fourth glume; 7. ovary and lodicules; 8. first glume of the pedicelled spikelets.