Trisetum pringlei

HABIT Perennial; caespitose. Culms erect; slender; 30–80 cm long; 2 -noded. Culm-internodes hollow. Culm-nodes constricted; brown. Lateral branches lacking. Leaf-sheaths glabrous on surface, or pubescent. Ligule an eciliate membrane; 1–2 mm long; erose. Leaf-blades flat, or involute; 1–12 cm long; 2–5 mm wide. Leaf-blade surface ribbed; scabrous; rough adaxially; puberulous; hairy adaxially.

INFLORESCENCE Inflorescence a panicle. Peduncle 5–15 cm long.

Panicle open, or contracted; lanceolate, or ovate; 10–20 cm long. Primary panicle branches whorled at most nodes; 4–8 cm long. Panicle branches scaberulous.

Spikelets appressed; solitary. Fertile spikelets pedicelled. Pedicels oblong.

FERTILE SPIKELETS Spikelets comprising 2–3 fertile florets; with a barren rhachilla extension. Spikelets oblong; laterally compressed; 4.5–6.5 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes 1.5 mm long; pubescent. Floret callus pubescent.

GLUMES Glumes persistent; shorter than spikelet; thinner than fertile lemma. Lower glume ovate; 1.5–2.6 mm long; 0.4–0.6 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume lateral veins absent. Lower glume apex acute. Upper glume oblong, or ovate; 3.5–4.5 mm long; 1–1.1 length of adjacent fertile lemma; membranous; 1-keeled; 3 -veined. Upper glume apex acute.

FLORETS Fertile lemma elliptic; 3.6–4 mm long; membranous; much thinner on margins; keeled; 5 -veined. Lemma surface scaberulous; rough below; glabrous, or pubescent; hairy below. Lemma apex acute; muticous, or mucronate. Principal lemma awn subapical. Palea embraced by lemma; 0.75 length of lemma. Palea keels scaberulous. Rhachilla extension pubescent.

FLOWER Anthers 3; 0.7–1.2 mm long. Ovary glabrous.

DISTRIBUTION South America: Mesoamericana.

NOTES Aveneae. Fl Costa Rica.

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