Microstegium japonicum

HABIT Annual; mat forming. Culms rambling; 20–80 cm long; rooting from lower nodes. Culm-nodes glabrous. Leaf-sheaths outer margin hairy. Ligule an eciliate membrane; 0.2–0.5 mm long. Leaf-blade base broadly rounded. Leaf-blades lanceolate, or ovate; 2–7 cm long; 6–12 mm wide. Leaf-blade midrib scarcely raised beneath. Leaf-blade surface glabrous. Leaf-blade apex acute.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 3–7; digitate; drooping; flexuous; 4–6 cm long. Central inflorescence axis 1–3 cm long. Rhachis tough; glabrous on margins. Rhachis internodes filiform; 3–5 mm long; 1.1–1.2 length of fertile spikelet.

Spikelets in pairs. Fertile spikelets pedicelled; 2 in the cluster. Pedicels filiform; terete; unequal; 1 mm long, or 2.5–3 mm long; glabrous.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 3–4 mm long; falling entire. Spikelet callus pubescent; base obtuse; attached transversely.

GLUMES Glumes dissimilar; firmer than fertile lemma. Lower glume oblong; 1 length of spikelet; cartilaginous; much thinner above; 2-keeled; keeled above; 2–4 -veined. Lower glume primary vein scaberulous. Lower glume surface concave; smooth. Lower glume apex emarginate, or acute. Upper glume elliptic; 1 length of spikelet; cartilaginous; without keels, or 1-keeled; 3 -veined. Upper glume apex acuminate.

FLORETS Basal sterile florets male; with palea. Lemma of lower sterile floret oblong; hyaline. Fertile lemma linear; 1.7–2 mm long; hyaline; without keel. Lemma apex entire; emarginate; awned; 1 -awned. Principal lemma awn apical; flexuous; with thread-like crinkled tip; 6–10 mm long overall. Palea absent or minute.

FLOWER Anthers 2; 0.5–0.7 mm long.

DISTRIBUTION Asia-temperate: Caucasus, China, and eastern Asia.

NOTES Andropogoneae. Fl China 2004.

Please cite this publication as detailed in How to Cite Version: 3rd February 2016.