GrassBase - The Online World Grass Flora

Descriptions

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

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

Poa jansenii

HABIT Perennial; caespitose; clumped densely. Basal innovations intravaginal. Culms 20–35 cm long. Leaf-sheaths smooth; glabrous on surface. Ligule an eciliate membrane; 3 mm long; acute. Leaf-blades conduplicate, or involute; 5–10 cm long; 1–2 mm wide. Leaf-blade venation with 11 secondary veins. Leaf-blade surface scabrous; rough adaxially; glabrous. Leaf-blade margins scabrous. Leaf-blade apex obtuse.

INFLORESCENCE Inflorescence a panicle. Peduncle scaberulous above.

Panicle open; ovate; 5–8 cm long. Primary panicle branches spreading, or reflexed; 1–2 -nate; 0.5–1.5 cm long. Panicle branches flexuous; scabrous.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 2 fertile florets; with a barren rhachilla extension. Spikelets oblong, or ovate; laterally compressed; 3.5–5 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes 0.3–0.5 mm long; smooth. Floret callus glabrous.

GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume oblong, or ovate; 2.1–3.5 mm long; 0.8–0.9 length of upper glume; membranous; 1-keeled; 3 -veined. Lower glume primary vein scabrous. Lower glume apex acute. Upper glume obovate; 2.5–3.7 mm long; 0.8–0.9 length of adjacent fertile lemma; membranous; 1-keeled; 3 -veined. Upper glume primary vein scabrous. Upper glume apex acute.

FLORETS Fertile lemma ovate; elliptic in profile; 3–4.1 mm long; membranous; keeled; 5 -veined. Lemma midvein scabrous. Lemma surface glabrous. Lemma apex acute. Palea keels scabrous; adorned above.

FLOWER Lodicules 2; membranous. Anthers 3; 1.3–1.5 mm long.

FRUIT Caryopsis with adherent pericarp. Hilum punctiform.

DISTRIBUTION Asia-tropical: Papuasia.

NOTES Poeae. Alp Fl N Guin 1994.

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