GrassBase - The Online World Grass Flora


W.D. Clayton, M. Vorontsova, K.T. Harman & H. Williamson

© Copyright The Board of Trustees, Royal Botanic Gardens, Kew.

Festuca flacca

HABIT Perennial; culms solitary, or caespitose; clumped loosely. Cataphylls inconspicuous. Rhizomes short; fleshy; not obviously scaly. Basal innovations extravaginal, or intravaginal. Culms erect; of moderate stature; straight, or curved; 110–150 cm long; 2–4 mm diam.; 3–8 -noded; with 0.5–0.66 of their length below uppermost node; 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; smooth. Leaf-sheath auricles absent. Ligule an eciliate membrane; 2–4.5 mm long; membranous; translucent, or white; lacerate; acute. Leaf-blade base symmetrical. Leaf-blades flexuous; flat; linear in section; 25–40 cm long; 4–9 mm wide; flaccid; dark 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 scabrous; rough on both sides; glabrous. Leaf-blade margins scaberulous; glabrous. Leaf-blade apex attenuate.

INFLORESCENCE Inflorescence a panicle; with 1 peduncles per sheath. Peduncle terete; eglandular; glabrous.

Panicle open; lanceolate; continuous; loose; secund; straight; 20–30 cm long. Primary panicle branches appressed, or ascending; moderately divided; 10–15 cm long; bearing spikelets almost to the base. Panicle branches straight; smooth.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 2–4 fertile florets; with diminished florets at the apex. Spikelets lanceolate; laterally compressed; 7–9 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; 1.2–2.4 mm long; 0.5–0.75 length of upper glume; coriaceous; mid-green; without keels; 1 -veined. Lower glume lateral veins absent. Lower glume apex acute, or acuminate. Upper glume linear; 2.3–3.5 mm long; 0.5–0.6 length of adjacent fertile lemma; coriaceous; dark green, or purple; without keels; 1 -veined. Upper glume lateral veins absent. Upper glume apex acute.

FLORETS Fertile lemma lanceolate; symmetrical; 4.5–5.5 mm long; chartaceous; pallid, or mid-green; without keel; 5 -veined. Lemma surface puberulous. Lemma apex awned; 1 -awned. Principal lemma awn filiform; 6–12 mm long overall. Palea 2 -veined. Palea keels scabrous; adorned all along; with hairs 4 mm long. Palea apex dentate; 2 -fid. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2. Anthers 3; 0.9–1.2 mm long. Ovary pubescent on apex.

FRUIT Caryopsis with adherent pericarp; sulcate on hilar side. Hilum linear; 0.66 length of caryopsis.

DISTRIBUTION South America: western South America.

NOTES Poeae. Stancik 2005.

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