Nassella arcaensis

HABIT Perennial; caespitose. Culms erect; robust; 100–150 cm long. Culm-internodes distally pubescent. Leaf-sheaths glabrous on surface. Leaf-sheath oral hairs pubescent. Ligule an eciliate membrane; 1 mm long; truncate. Leaf-blades 25–50 cm long; 3–6 mm wide. Leaf-blade surface ribbed; scaberulous; rough adaxially. Leaf-blade apex attenuate.

INFLORESCENCE Inflorescence a panicle.

Panicle open; ovate; 25–50 cm long. Primary panicle branches spreading; whorled at most nodes; 7–15 cm long. Panicle axis smooth. Panicle branches scaberulous; rough distally.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels puberulous.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; subterete; 11–12 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus evident; 1 mm long; pubescent; acute.

GLUMES Glumes persistent; similar; exceeding apex of florets; thinner than fertile lemma. Lower glume lanceolate; 1 length of upper glume; membranous; without keels; 3 -veined. Lower glume apex acuminate. Upper glume lanceolate; 11–12 mm long; membranous; without keels; 3 -veined. Upper glume apex acuminate.

FLORETS Fertile lemma lanceolate; subterete; 8–9 mm long; coriaceous; without keel; 5 -veined. Lemma surface pilose. Lemma margins convolute; covering most of palea. Lemma apex awned; 1 -awned. Principal lemma awn bigeniculate; 40 mm long overall; with a straight or slightly twisted column. Palea 0 -veined; without keels.

FLOWER Anthers 3. Stigmas 2. Ovary glabrous.

FRUIT Caryopsis with adherent pericarp; fusiform. Hilum linear.

DISTRIBUTION South America: southern South America.

NOTES Stipeae. Hitchcock 1995.

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