A small tufted perennial grass.
The plant consists of prostrate stems and stolons, filiform and wiry. Stems vary in length from 2 to 18 inches, prostrate or erect, rooting at the lower nodes; flowering branches always ascending.
The leaf-sheath is glabrous, finely striate, shorter than the internode. The ligule is a very short ciliated membrane.
The leaf-blade is narrow linear, pungent, somewhat rigid, flat, distichous, base rounded with or without a few long hairs and varies in length from 1/4 to 1 inch and in breadth from 1/20 to 1/16 inch, but in plants growing in rich moist soils the leaves become longer reaching 3-1/2 inches in length.
The inflorescence is a narrow spiciform panicle with appressed branches and spikelets, sometimes interrupted, varying in length from 3/4 to 1-1/4 inch; both the peduncle and the main rachis are glabrous, and the latter wavy.
Fig. 180.—Sporobolus tremulus.
1. Spike; 2. spikelet; 3 and 4. first and second glumes; 5 and 6. third glume and its palea; 7. ovary and anthers.
The spikelets are 1/16 inch long, oblong-lanceolate, pale, crowded, glabrous, shortly pedicelled on thinly scaberulous filiform short branches. There are three glumes in the spikelet, and all the glumes are membranous and thin. The first glume is a little shorter than the second and about two-third the length of the third glume and 1-nerved. The second glume is a little shorter than the third or equal to but not longer, oblong-lanceolate, subacute or obtuse, 1-nerved and obscurely scaberulous at the back along the nerve. The third glume is broadly oblong, subacute or obtuse, 1-nerved, glabrous, with a palea as long as the glume; the palea is 2-nerved, oblong and truncate at the apex. Stamens are three and anthers are pale greenish yellow. Stigmas are pale. Lodicules are two, small.
This grass is an excellent one for binding the soil and may also prove successful as a fodder grass. It usually flourishes in moist situations, in sandy loams and rich heavy soils.