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.

Trisetum arduanum

HABIT Perennial; caespitose; clumped loosely. Culms erect; 30–60 cm long. Leaf-sheaths 3–6 cm long; smooth, or scaberulous; glabrous on surface, or puberulous. Ligule an eciliate membrane; 0.2–0.3 mm long; erose. Leaf-blades involute; 10–20(–30) cm long; 0.5–1.5(–4) mm wide. Leaf-blade surface glabrous, or puberulous; hairy adaxially. Leaf-blade margins scaberulous.

INFLORESCENCE Inflorescence a panicle. Peduncle smooth, or scaberulous above.

Panicle contracted; linear, or oblong; (3–)8–18(–27) cm long; 0.7–3.5(–5) cm wide; contracted about primary branches. Primary panicle branches ascending; bearing spikelets almost to the base. Panicle axis scaberulous. Panicle branches scaberulous.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels scaberulous.

FERTILE SPIKELETS Spikelets comprising 2–3 fertile florets; with a barren rhachilla extension. Spikelets oblong; laterally compressed; 4–7.5 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes pilose; with 1–2 mm long hairs. Floret callus pubescent. Floret callus hairs 0.2–0.5 mm long.

GLUMES Glumes persistent; similar; exceeding apex of florets; similar to fertile lemma in texture, or firmer than fertile lemma; shiny; gaping. Lower glume elliptic; 0.66–0.75 length of upper glume; hyaline; pallid, or yellow; 1-keeled. Lower glume apex acute. Upper glume lanceolate, or elliptic; hyaline; pallid, or yellow; 1-keeled. Upper glume apex acute.

FLORETS Fertile lemma elliptic; 4.5–6 mm long; membranous; shiny; keeled; 5 -veined. Lemma surface papillose. Lemma apex dentate; 2 -fid; awned; 1 -awned. Principal lemma awn dorsal; arising 0.75 way up back of lemma; straight, or curved; 3.5–8 mm long overall. Palea gaping; hyaline. Palea keels scaberulous; adorned above; with 0.66 of their length adorned.

FLOWER Lodicules 2; 1 mm long. Anthers 3; 1.2–2 mm long.

FRUIT Caryopsis with adherent pericarp; 2.6 mm long.

DISTRIBUTION Australasia: New Zealand.

NOTES Aveneae. Edgar 2000.

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