Trisetum glaciale

HABIT Perennial; caespitose. Butt sheaths persistent and investing base of culm; with fibrous dead sheaths. Culms 8–20 cm long. Leaf-sheaths pubescent. Ligule an eciliate membrane. Leaf-blades 2–5 cm long; 0.5–1 mm wide; stiff. Leaf-blade surface pubescent. Leaf-blade margins cartilaginous.

INFLORESCENCE Inflorescence a panicle.

Panicle spiciform; oblong; 2.5–3 cm long; 0.7–1 cm wide. Panicle branches scabrous.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 1–2 fertile florets; with a barren rhachilla extension. Spikelets oblong, or cuneate; laterally compressed; 5 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes pilose; with 1 mm long hairs. Floret callus pubescent.

GLUMES Glumes persistent; similar; reaching apex of florets; thinner than fertile lemma; shiny; gaping. Lower glume elliptic; 5 mm long; 1 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume lateral veins absent. Lower glume apex acute. Upper glume elliptic; 5 mm long; 1.1–1.5 length of adjacent fertile lemma; membranous; 1-keeled; 3 -veined. Upper glume apex acute.

FLORETS Fertile lemma obovate; 3.5–4.5 mm long; cartilaginous; much thinner above; keeled; 5 -veined. Lemma surface asperulous. Lemma apex dentate; 2 -fid; awned; 1 -awned. Principal lemma awn dorsal; arising 0.6–0.7 way up back of lemma; geniculate; 4–5 mm long overall; with twisted column. Palea gaping; hyaline. Palea keels scaberulous.

FLOWER Lodicules 2; membranous. Anthers 3; 2 mm long. Ovary pubescent all over.

FRUIT Caryopsis with adherent pericarp. Hilum punctiform.

DISTRIBUTION Europe: southwestern.

NOTES Aveneae. Fl Eur.

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