Festuca of North America


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

Festuca minutiflora Rydb.


Bull. Torrey Bot. Club 32: 608. 1905. F. ovina var. minutiflora (Rydb.) Howell, Leafl. West. Bot. 6: 151. 1951. Type: U.S.A. Colorado: Cameron Pass, 13 July 1896, Baker s.n. Holotype: NY! Part of the type US!

F. brevifolia var. endotera St.-Yves, Candollea 2: 254. 1925. F. brachyphylla var. endotera (St.-Yves) Litard. Candollea 10: 108. 1945. Type: U.S.A. Colorado: near Pagosa Peak, August 1899, C.F. Baker 176. Lectotype: GH! Isolectotype NY! (Frederiksen 1979).

Habit. Plants deep green, 4–30(–40) cm high, densely tufted (in small tufts), tiller bases stiffly erect, bases not purplish (usually), horizontal rooting stems absent. Vegetative shoots arising from within existing sheaths.

Vegetative morphology. Sheaths glabrous, not conspicuous at the base of the plant, remaining entire, not conspicuously splitting between the veins, closed more than half their length or open more than half their length (observed as approximately half the length). Collars glabrous. Auricles represented by distinct, erect, swellings. Auricular cilia absent. Ligules 0.1–0.3 mm long, ciliate (narrow leaves, tiny ligules, tiny cilia). Leaf blades 1–7(–10) cm long, more or less lax. Adaxial blade surfaces with trichomes, abaxial blade surfaces glabrous. Leaf blades plicate; 0.2–0.33–0.45 mm wide, (0.2–)0.4–0.45–0.55 mm deep (conspicuously narrow and triangular in outline relative to most other Festuca taxa in North America). Veins 3–5. Adaxial to abaxial sclerenchyma strands absent. Abaxial sclerenchyma poorly developed, in discrete, relatively narrow strands opposite the veins. Ribs 1 (well defined, 0–2 variously defined). Uppermost culm leaf sheaths not inflated. Flag leaf blades 0.8–3 cm long. Culm nodes becoming exposed (usually) or never exposed (rarely), 1 (when visible); internodes glabrous.

Floral morphology. Inflorescence 1–4(–5) cm long. Inflorescence branches at the lowest node 1–3, appressed after anthesis (or slightly open), 0.15–1.5 cm long. Rachis rounded in cross section or angular in cross section, trichomes mainly on the ridges or trichomes over the entire surface (sometimes almost glabrous). Spikelets aggregated towards the ends of the branches; 1–3 on the longest branches; 2.5–5 mm long, 1.5–2.5 mm wide. Proliferating spikelets absent (not recorded for this taxon). Florets 2–5 (usually 2). Glumes unequal, with trichomes (slightly scaberulous), vestiture at the apex only, margins ciliate (especially at the apex). First glume 1.3–2.5 mm long, veins 1. Second glume shorter than the first lemma, 2–3.4 mm long, veins 3. Rachilla internodes 0.7–0.8 mm long, antrorsely scabrous. Lemma callus not elongated. Lemma 2–3.4 mm long, nerveless in dorsal view or sometimes with only the centre vein distinct, with trichomes (sparse), trichomes on the upper portion only; apex entire. Lemma awn 0.5–1.5(–1.7) mm long. Palea 2.7–3.1 mm long, distinctly pubescent between the keels. Lodicules with marginal teeth, glabrous, 0.45–0.6 mm long. Anthers (0.4–)0.7–1.1 mm long. Ovary apex pubescent (with a few sparse hairs). Caryopsis 2–2.5 mm long.

Cytology. 2n = 28.

Habitat and Distribution. Native; alpine. Canada: Alta., B.C., Yukon; Southwestern USA: Ariz., Calif., Nev.; Rocky Mountains USA: Colo., Idaho, Mont., Utah, Wyo.; South Central USA: N. Mex.

Classification. Subg. Festuca L.


Frederiksen (1979) considered F. minutiflora a neglected species. She mapped the distribution and since that time we have found more specimens particularly in Canada (Argus and Aiken 1987, Aiken and Darbyshire 1990). While agreeing with Frederiksen (1979) that F. brevifolia var. utahensis St.-Yves is synonymous with F. minutiflora, we suggest that F. brachyphylla var. endotera (St.-Yves) Litard. is synonymous with F. earlei Rydb. (see the notes for F. earlei).

Frederiksen (1979) included F. brevifolia var. utahensis in F. minutiflora "only with some hesitation". She noted that "the top of the caryopsis is hairy, but it deviates, especially in having more florets per spikelet and broader leaves. However, there are transitional specimens even among the few specimens examined." Both F. minutiflora and F. earlei show phenotypic plasticity with evidence on herbarium labels suggesting that small and large plants have often come from different microhabitats at the same location (Baker 175 and 176 collections). Large specimens of F. minutiflora approach the dimensions of small to medium size specimens of F. earlei, but have a finer more delicate form when the two species are compared. The degree of this difference is indicated in that large specimens of F. earlei are sufficiently robust to have been identified as F. rubra, while many specimens of F. minutiflora have previously been identified as F. brachyphylla Schult. & Schult. f.

Rydberg (1905) gave the ligule length for F. minutiflora as 0.75 mm, but all specimens examined to date have ligules less than 0.5 mm long. Ligules in F. earlei are 0.1–1.0 mm long.


• Herbarium specimen. Plant of F. minutiflora from Rocky Mountains National Park, Larimer Co., 11,600 ft.; dry, sandy soil. 26 Aug. 1964, Dale W. McNeal Jr. No. 316. Specimen at University of Colorado, Boulder, No. 197573. Photograph of the specimen at DAO. Specimen re-examined 1994. • Holotype specimen: NY. Label reads, "Plants of North Colorado collected by Carl. F. Baker. Festuca ovina capillata (Det. Scrib.) Cameron Pass, 7–13–96, Altitude 10,000 feet". Annotated by S. Frederiksen in 1979 and indicated as the holotype by her in Bot. Not. 132: 317. 1979. • Ovary with sparse hairs. An ovary of F. minutiflora showing a few dense hairs at the apex with styles removed. Scanned with permission from Frederiksen (1979); photographed at x 100. • Leaf anatomy. Leaf cross section of F. minutiflora. Leaf blades are 0.2–0.33–0.45 mm wide and (0.2-)0.4–0.45–0.55 mm deep, conspicuously narrow and triangular in outline relative to most other F. taxa in North America. There are 3–5 veins. Adaxial to abaxial sclerenchyma strands are absent. Abaxial sclerenchyma strands are poorly developed, in discrete, relatively narrow strands opposite the veins. There is one well defined rib and 0–2 variously defined ribs. • Distribution map

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).