Fig. 184.—Sporobolus commutatus.
1. A portion of a branch; 2. spikelet; 3, 4 and 5. first, second and the third glume; 6. palea of the third glume; 7. ovary and anthers; 8 and 9. grain.
The inflorescence is diffuse, pyramidal, 1 to 3 inches by 3/4 to 2 inches, on a slender glabrous peduncle 1 to 6 inches long, main rachis is slender and angled, with a glandular streak or without it. Branches are effuse, fine, capillary (more so than in S. coromandelianus), obliquely ascending, never stiff and horizontal, verticillate or irregularly subverticillate, the lowest whorl of five to twelve and the others three to seven branches; the rachis of the branches is obscurely scaberulous, slightly swollen at the point of insertion; branchlets are never appressed to the branch, always drooping and spreading on all sides, and bearing two to four spikelets.
The spikelets are about 1/16 inch long, ovate-lanceolate, acute or acuminate dark or pale green, sometimes purplish, solitary or two to four on long slender pedicels, drooping, never appressed, and with glandular streaks. There are three glumes. The first glume is minute, hyaline, ovate, obtuse or acute, nerveless. The second glume is five or six times as long as the first, ovate lanceolate, 1-nerved, acuminate. The third glume is equal to or a little shorter than the second, ovate-lanceolate, acute, 1-nerved paleate; palea is equal to the third glume, 2-nerved splitting into two halves between the nerves. Anthers are three and purple in colour. Stigmas are white and feathery. Grain as in S. coromandelianus.
In Flora of British India, this plant is included under Sporobolus coromandelianus. These two plants (S. coromandelianus and S. commutatus) are quite distinct and grow side by side. As the differences are not easily seen in herbarium specimens the two plants are put together under the one species S. coromandelianus. The branches are tufted and are usually decumbent at base, leaves quite green and somewhat broad in S. coromandelianus; and in S. commutatus, branches are usually not decumbent at base, generally erect from the base and leaves are green glaucous and somewhat narrow. The most striking difference, however, is in the panicle. The branches of the panicle are always stiff and horizontal in S. coromandelianus and the spikelets are appressed to the branches and never spreading or drooping, whereas in S. commutatus the branches are never stiff and horizontal, always obliquely ascending and the spikelets are spreading and drooping. Judging from living plants these two are undoubtedly distinct and so this plant is treated as a distinct species retaining Kunth's name Sporobolus commutatus. Enumeratio Plantarum, Pl. I, 214.
Distribution.—This occurs in Coimbatore, Madras and Bellary Districts; but it is not so common nor so widely distributed as S. coromandelianus, L.
Fig. 185.—Sporobolus scabrifolius.