Fig. 97.—Panicum distachyum.
Panicum distachyum, L.
This grass is an annual. Stems are slender, rarely stout, creeping and rooting at the nodes, pale green or purplish, with erect or ascending slender branches, varying in length from 10 to 15 inches, glabrous or pubescent, channelled near the nodes.
The leaf-sheath is glabrous or glabrescent and sometimes hirsute; margin is ciliate. The ligule is a fringe of short hairs. Nodes are glabrous or pubescent.
The leaf-blade is lanceolate or narrowly lanceolate, base cordate and subamplexicaul, glabrous or rarely sparsely hairy on both sides; margins are wavy here and there, finely serrate with tubercle-based hairs towards the base, the midrib is slender, not prominent and veins not distinct. There is considerable variation in leaves especially in the length. In the ordinary form it varies from 1/2 to 3 inches and even up to 6 or 7 inches sometimes in length and the breadth from 1/8 to 1/4 inch. In one form which is separated as a variety (var. brevifolium, Wight and Arnott,) the leaves are always short and broad, ovate-lanceolate never exceeding 1 inch in length.
The inflorescence consists of two or three, very rarely four erect or spreading distant spikes on a somewhat slender very hairy peduncle. Spikes are from 1/2 to 2 inches; rachis is slender, flexuous, flattened, scaberulous, with a few long hairs scattered singly along the margins or without these hairs.
Fig. 98.—Panicum distachyum.
1 and 2. Front and back view of a portion of a spike; 3, 4, 5, and 6. the first, second, third and the fourth glume, respectively; 5a and 6a. palea of the third and the fourth glume, respectively; 7. anthers and ovary.