Trisetum tonduzii

HABIT Perennial. Culms erect; 45–85 cm long. Ligule an eciliate membrane; 1.5–3 mm long. Leaf-blades 10–20 cm long; 4–6 mm wide. Leaf-blade surface glabrous, or pubescent; hairy adaxially.

INFLORESCENCE Inflorescence a panicle.

Panicle open; pyramidal; 15–20 cm long. Panicle branches scabrous.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels filiform.

FERTILE SPIKELETS Spikelets comprising 2 fertile florets; with a barren rhachilla extension. Spikelets oblong; laterally compressed; 4–6.5 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes pilose. Floret callus bearded. Floret callus hairs 0.25–0.5 length of lemma.

GLUMES Glumes persistent; similar; reaching apex of florets; gaping. Lower glume lanceolate; 4–6.5 mm long; 1 length of upper glume; membranous; purple; 1-keeled; 1 -veined. Lower glume apex acute. Upper glume lanceolate; 4–6.5 mm long; 1.1–1.5 length of adjacent fertile lemma; membranous; purple; 1-keeled; 3 -veined. Upper glume apex acute.

FLORETS Fertile lemma obovate; 2.8–6 mm long; chartaceous; keeled; 5 -veined. Lemma lateral veins excurrent. Lemma surface scaberulous. Lemma apex lobed; 2 -fid; incised 0.33 of lemma length; awned; 5 -awned. Principal lemma awn dorsal; arising 0.5–0.6 way up back of lemma; geniculate; 7–13 mm long overall; with a straight or slightly twisted column. Lateral lemma awns arising on apex of lobes and on inner edge of lobes; 1 mm long; shorter than principal. Palea gaping; 0.8 length of lemma; hyaline. Rhachilla extension 0.3–0.5 length of fertile floret.

FLOWER Lodicules 2; membranous. Anthers 3; 1.7–2 mm long. Ovary glabrous.

FRUIT Caryopsis with adherent pericarp. Hilum punctiform.

DISTRIBUTION South America: Mesoamericana.

NOTES Aveneae. WDC.

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