Festuca of North America


S. G. Aiken, M. J. Dallwitz, C. L. McJannet, and L. L. Consaul

Festuca rubra L. s.l. (data as synthesised)

Habit. Plants bisexual. Plants yellowish green (3) or bluish gray green (3) or deep green (3), 8–48.2–120 cm high, densely tufted (1) or not densely tufted, tiller bases stiffly erect (2) or not stiffly erect, bases purplish or not purplish (2), horizontal rooting stems present or absent (1). Vegetative shoots arising from within existing sheaths (1), or arising outside, or breaking through the base of existing sheaths.

Vegetative morphology. Sheaths glabrous (3) or glabrescent (2) or with trichomes (4), not conspicuous at the base of the plant, splitting between the veins (5) or remaining entire, not conspicuously splitting between the veins (1), closed more than half their length. Collars glabrous. Auricles represented by distinct, erect, swellings (3) or absent (4). Auricular cilia absent (2/2). Ligules 0.1–0.2917–0.5 mm long, ciliate (5/5). Leaf blades 3–18.8–37 cm long, erect, stiffish (3) or more or less lax (4). Adaxial blade surfaces glabrous (1) or with trichomes (5), abaxial blade surfaces glabrous or with trichomes (1). Leaf blades flat (3) or plicate, 1–2.5–4 mm wide; 0.3–0.7458–1.4 mm wide, 0.5–1.033–2 mm deep. Veins 5 (5), or 6 (4), or 7 (5), or 8 (3), or 9 (2), or 10–12 (1). Adaxial to abaxial sclerenchyma strands absent. Abaxial sclerenchyma poorly developed (2) or well developed (5), in discrete, relatively narrow strands opposite the veins. Ribs 5 (3/4), or 7–9 (1/4). Uppermost culm leaf sheaths not inflated. Flag leaf blades 0.4–5.29–11 cm long. Culm nodes never exposed (2) or becoming exposed, 1 (4/4) or 2 (2/4) or 3 (1/4); internodes glabrous, or scabrous-hirsute (1).

Floral morphology. Inflorescence paniculate, 2–6.916–20 cm long. Inflorescence branches at the lowest node 1 or 2 (5) or 3 (3) or 4 (1), appressed after anthesis (5) or spreading (2), 0–2.975–8 cm long. Rachis angular in cross section, trichomes mainly on the ridges (4/5) or trichomes over the entire surface (2/5). Spikelets loosely scattered in an open panicle with slender branches (1/4) or aggregated towards the ends of the branches (4/4); 1–4 on the longest branches; 6–9.258–14 mm long, 0.3–2.48–4.5 mm wide. Proliferating spikelets present (1), or absent. Florets 2 (2), or 3–4 (4), or 5–6, or 7 (5), or 8 (3), or 9 (2), or 10 (1). First glumes present. Glumes unequal, glabrous (3) or with trichomes (4), vestiture at the apex only (3/4) or over most of the outer surface (2/4), margins ciliate (4) or not ciliate (2). First glume 1.5–3.116–4.5 mm long, veins 1 or 2–3 (1). Second glume shorter than the first lemma, 3–4.458–6 mm long, veins 3. Rachilla internodes 1–1.25–1.5 mm long, antrorsely scabrous. Lemma callus not elongated. Lemma 4–5.95–8 mm long, with 5 distinct veins in dorsal view (1) or nerveless in dorsal view or sometimes with only the centre vein distinct (5), glabrous (3) or with trichomes (5), trichomes on the upper portion only (2/5) or over the entire surface (3/5); apex entire or apically cleft (1). Lemma awn present. Lemma awn 0.2–1.379–5 mm long. Palea 4.5–5.69–7 mm long, distinctly pubescent between the keels. Lodicules with marginal teeth (5/5), glabrous (5/5) or ciliate (1/5), 0.7–0.99–1.5 mm long. Anthers 2.2–3.158–4.5 mm long. Ovary apex glabrous. Caryopsis 2–3.35–4.5 mm long.

Cytology. 2n = 14–46–70.

Classification. Subg. Festuca L. (5/5).


Data as synthesised by Intkey from the six putative subspecies of F. rubra in the database. Comments (numbers in brackets) indicate the distribution of the character states among the subspecies (but these comments are not visible in Intkey). A version with these comments removed and other comments added is included in the database as F. rubra L. s.l.

The interactive key provides access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting specified attributes, and summaries of attributes within groups of taxa.

Cite this publication as: ‘Aiken, S.G., Dallwitz, M.J., McJannet, C.L. and Consaul, L.L. 1996 onwards. Festuca of North America: descriptions, illustrations, identification, and information retrieval. Version: 19th October 2005. http://delta-intkey.com’. Aiken, Dallwitz, McJannet, and Consaul (1997) should also be cited (see References).