GrassBase - The Online World Grass Flora


W.D. Clayton, M. Vorontsova, K.T. Harman & H. Williamson

© Copyright The Board of Trustees, Royal Botanic Gardens, Kew.

Diarrhena japonica

HABIT Perennial; caespitose; clumped loosely. Cataphylls evident. Rhizomes short; knotty. Culms erect, or geniculately ascending; slender; 50–80 cm long; 1–1.5 mm diam.; 4–5 -noded. Ligule an eciliate membrane; 0.5–1 mm long. Leaf-blades lanceolate; 20–30 cm long; 8–15 mm wide. Leaf-blade venation with distinct cross veins. Leaf-blade apex acute.

INFLORESCENCE Inflorescence a panicle.

Panicle open; elliptic; effuse; 10–20 cm long; 8–20 cm wide. Primary panicle branches spreading; 1–2 -nate; 2–7 cm long; bearing 1–6 fertile spikelets on each lower branch. Panicle branches capillary.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels filiform; 1.5–2.5 mm long; scabrous.

FERTILE SPIKELETS Spikelets comprising 1–3 fertile florets; without rhachilla extension. Spikelets obovate; laterally compressed; 3–5 mm long; breaking up at maturity; disarticulating below each fertile floret.

GLUMES Glumes persistent; dissimilar; shorter than spikelet. Lower glume lanceolate; 0.8–1 mm long; 0.5–0.6 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume lateral veins absent. Lower glume apex acute. Upper glume lanceolate, or ovate; 1.5–1.6 mm long; 0.3–0.4 length of adjacent fertile lemma; membranous; 1-keeled; 1 -veined. Upper glume lateral veins absent. Upper glume apex acute.

FLORETS Fertile florets appressed to rhachilla. Fertile lemma lanceolate, or ovate; 3.5–5 mm long; cartilaginous; without keel; rounded except near apex; 3 -veined. Lemma apex obtuse. Palea 1 mm long; 2 -veined. Palea keels smooth.

FLOWER Lodicules 2; membranous. Anthers 3; 0.7–1.2 mm long.

FRUIT Caryopsis with tardily free pericarp; ellipsoid, or obovoid; exposed between gaping lemma and palea at maturity; 2.5–3.2 mm long; apex umbonate.

DISTRIBUTION Asia-temperate: China and eastern Asia.

NOTES Diarrheneae. Koyama.

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