Festuca rivularis

HABIT Perennial; caespitose; clumped loosely. Rhizomes elongated. Butt sheaths persistent and investing base of culm; with compacted dead sheaths. Basal innovations extravaginal. Culms 30–70 cm long. Leaf-sheaths tubular for much of their length; with 1 of their length closed; with flat margins; glabrous on surface. Ligule an eciliate membrane; 0.5 mm long. Leaf-blades conduplicate; 0.6–1.1 mm wide; light green. Leaf-blade midrib keeled beneath. Leaf-blade venation comprising 7–9 vascular bundles; with sclerenchyma strands below veins; with subepidermal sclerenchyma strands similar in size; with subepidermal sclerenchyma free from veins. Leaf-blade surface ribbed; smooth, or scaberulous; pubescent; sparsely hairy.

INFLORESCENCE Inflorescence a panicle.

Panicle open; lanceolate; loose; 10–22 cm long. Primary panicle branches spreading. Panicle branches smooth, or scaberulous.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets with diminished florets at the apex. Spikelets oblong; laterally compressed; 8–10 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes obscured by lemmas.

GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume lanceolate; chartaceous; without keels; 1 -veined. Lower glume lateral veins absent. Lower glume apex acute. Upper glume lanceolate; 4.3–6 mm long; 0.7–0.8 length of adjacent fertile lemma; chartaceous; without keels; 3 -veined. Upper glume apex acuminate.

FLORETS Fertile lemma oblong; 6–7.1 mm long; chartaceous; mid-green, or purple; without keel; 5 -veined. Lemma apex acute; mucronate, or awned; 1 -awned. Principal lemma awn 0.3–2 mm long overall. Palea 2 -veined. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2. Anthers 3. Ovary glabrous.

FRUIT Caryopsis with adherent pericarp; ellipsoid. Hilum linear. Disseminule comprising a caryopsis and palea.

DISTRIBUTION Europe: southwestern.

NOTES Poeae. Fl Eur 1995.

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