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 roemeri

HABIT Perennial; caespitose; clumped densely. Rhizomes absent. Culms erect; (35–)50–90(–100) cm long. Culm-internodes smooth; distally glabrous. Leaf-sheaths open for most of their length; with 0.25–0.5 of their length closed; smooth, or scaberulous; glabrous on surface, or hirsute. Ligule an eciliate membrane; 0.1–0.5 mm long. Collar glabrous. Leaf-blades conduplicate; 0.5–1(–1.2) mm wide. Leaf-blade venation comprising 5–7(–9) vascular bundles; with 5–9 inner ridges; with sclerenchyma strands below veins; with 5–7 subepidermal sclerenchyma strands; with subepidermal sclerenchyma free from veins; with sclerenchyma strands widened to form a discontinuous subepidermal layer, or with unevenly thickened subepidermal sclerenchyma layer on the underside. Leaf-blade surface smooth, or scaberulous; rough adaxially; glabrous, or puberulous; hairy on both sides.

INFLORESCENCE Inflorescence a panicle.

Panicle open, or contracted; elliptic, or ovate; (7–)8–20(–25) cm long. Primary panicle branches appressed, or ascending; 1–2 -nate; bearing 2–4 fertile spikelets on each lower branch.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 4–6 fertile florets; with diminished florets at the apex. Spikelets oblong; laterally compressed; 9–13.5 mm long; breaking up at maturity; disarticulating below each fertile floret.

GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume lanceolate; (2–)2.5–5 mm long; 0.66–0.75 length of upper glume; membranous; without keels; 1 -veined. Lower glume lateral veins absent. Lower glume surface smooth, or scabrous; rough above. Lower glume apex acute. Upper glume lanceolate, or elliptic; 4–6.2 mm long; 0.9 length of adjacent fertile lemma; membranous; without keels; 3 -veined. Upper glume surface smooth, or scabrous; rough above. Upper glume apex acute.

FLORETS Fertile lemma elliptic; 5–7(–8.2) mm long; chartaceous; without keel; 5 -veined. Lemma surface scabrous; rough above. Lemma apex acute; awned; 1 -awned. Principal lemma awn (2–)3–5 mm long overall. Palea 2 -veined. Palea surface smooth, or scabrous. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Anthers 3; (2.6–)2.8–3.6(–4) mm long. Ovary glabrous.

FRUIT Caryopsis with adherent pericarp. Hilum linear.

DISTRIBUTION North America: western Canada, northwest USA, and southwest USA.

NOTES Poeae. Fl N Amer 2007.

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