Festuca quadridentata

HABIT Perennial; caespitose; clumped moderately. Cataphylls inconspicuous. Rhizomes short; not obviously scaly. Basal innovations extravaginal, or intravaginal. Culms erect; robust; straight, or curved; 100–150 cm long; without nodal roots. Culm-internodes terete; smooth. Culm-nodes without exudate; glabrous. Lateral branches lacking. Leaves basal and cauline; 3–5 per branch. Leaf-sheaths tight; unthickened at base; open for most of their length; without keel; striately veined; scaberulous; glabrous on surface. Ligule an eciliate membrane; 5–8 mm long; membranous; translucent, or white; entire, or lacerate; acute. Leaf-blade base symmetrical. Leaf-blades straight, or flexuous; convolute; linear in section; 35–40 cm long; 0.7–0.8 mm wide; 6–10 cm long at summit of culm; herbaceous; firm, or flaccid; mid-green, or glaucous, or grey-green. Leaf-blade midrib evident. Leaf-blade venation distinct; with subepidermal sclerenchyma strands similar in size; with subepidermal sclerenchyma attached to veins above and below; without layer of subepidermal sclerenchyma masking vein striation. Leaf-blade surface scaberulous; rough adaxially; glabrous. Leaf-blade margins scabrous; glabrous. Leaf-blade apex acute.

INFLORESCENCE Inflorescence a panicle; with 1 peduncles per sheath. Peduncle straight, or flexuous; terete; eglandular; glabrous.

Panicle open; ovate, or pyramidal; continuous; dense; equilateral, or secund; straight; 40 cm long. Primary panicle branches ascending, or drooping; profusely divided; 8–16 cm long; naked below. Panicle branches straight, or arcuate, or flexuous; smooth, or scaberulous.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels 1–2 mm long; smooth, or scaberulous.

FERTILE SPIKELETS Spikelets comprising 4–6 fertile florets; with diminished florets at the apex. Spikelets oblong; laterally compressed; 11–13(–15) mm long; breaking up at maturity; disarticulating below each fertile floret. Spikelet callus glabrous. Rhachilla internodes scaberulous. Floret callus glabrous.

GLUMES Glumes persistent; similar; subequal in width; shorter than spikelet. Lower glume lanceolate; (3.5–)4–5 mm long; 0.75–0.85 length of upper glume; membranous, or chartaceous; pallid, or mid-green, or purple; without keels; 1 -veined. Lower glume lateral veins absent. Lower glume apex acute. Upper glume lanceolate; 4.5–5.5 mm long; 0.5–0.66 length of adjacent fertile lemma; chartaceous; pallid, or light green, or purple; without keels; 3 -veined. Upper glume apex acute.

FLORETS Fertile lemma oblong; symmetrical; 7.8–8.3 mm long; chartaceous; pallid, or light green; without keel; 5 -veined. Lemma lateral veins prominent. Lemma surface scabrous; glabrous, or puberulous. Lemma apex erose, or dentate; 3–4 -fid; obtuse; mucronate. Principal lemma awn 0–0.5 mm long overall. Palea 1 length of lemma; 2 -veined. Palea keels scabrous. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2. Anthers 3; 4 mm long. Ovary glabrous.

FRUIT Caryopsis with adherent pericarp. Hilum linear.

DISTRIBUTION South America: western South America.

NOTES Poeae. Stancik 2005.

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