Festuca of North America


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

Festuca kingii (S. Watson) Cassidy


Colo. Agric. Exp. Stn. Bull. 12: 36. 1890. Poa kingii S. Watson, in King, Rep. Geol. Explor. 40th parallel 5: 387. 1871. Festuca watsoni Nash in Britt. Man. Fl. N. States and Canada: 148. 1901. Wasatchia kingii (S. Watson) M. E. Jones, Contrib. West. Bot. 14: 16. 1912. Hesperochloa kingii (S. Watson) Rydb., Bull. Torrey Bot. Club 39: 106. 1912. Leucopoa kingii (S. Watson) W. A. Weber, Univ. Colo. Stud. Ser. Biol. 23: 2. 1966. Type: U.S.A. Nevada: Elko Co., East Humbolt (Ruby) Mountains, July 1868, Watson 1317. The location of the type specimen has been searched for by W. A. Weber and other botanists, but it has not been found (S. J. Darbyshire, personal communication 1994).

Festuca confinis Vasey, Bull. Torrey Bot. Club 11: 126. 1884. Type: Colorado: Peu (error for Pen) Gulch, altitude 8000 feet, in 1884, Vasey. Holotype: US!

Habit. Plants dioecious. Plants bluish gray green, 30–100 cm high, densely tufted (bases to 2 m in diameter), tiller bases stiffly erect, bases purplish or not purplish (usually predominantly straw coloured), horizontal rooting stems present (often absent on herbarium specimens). Vegetative shoots arising from within existing sheaths.

Vegetative morphology. Sheaths glabrous or glabrescent or with trichomes (veins very prominent), conspicuous at the base of the plant, persisting for more than 1 year, remaining entire, not conspicuously splitting between the veins, open more than half their length (prophylls 1–2 cm long with 2–3 rows of trichomes along the veins, occur among the sheaths, e.g. US 919615; prophylls are rarely preserved and are distinct from the glabrous rhizome scale leaves). Collars glabrous. Auricles represented by distinct, erect, swellings or absent. Auricular cilia absent. Ligules 0.8–2(–3.5) mm long, ciliate (sometimes sparsely so). Leaf blades 14–30 cm long (glaucous and coarsely striate), erect, stiffish. Adaxial blade surfaces glabrous or with trichomes (sparsely scaberulous to scabrous), abaxial blade surfaces glabrous (but often with prominent silica deposits in short cells). Leaf blades flat (usually) or plicate (leaves developed later in the growing season may be tightly rolled and appear young, but in cross section have heavily developed sclerenchyma), 1.5–4(–7) mm wide; 0.65–0.93–1.25 mm wide, 1.05–1.39–1.97 mm deep (6 leaves from 4 specimens). Veins 10–16. Adaxial to abaxial sclerenchyma strands present. Abaxial sclerenchyma well developed, in broad bands or continuous. Ribs 10–16. Uppermost culm leaf sheaths not inflated. Flag leaf blades 2.3–12 cm long. Culm nodes never exposed; internodes glabrous.

Floral morphology. Inflorescence 7–20 cm long (on both male and female plants). Inflorescence branches at the lowest node 2(–3) (arising at the same position on one side of the rachis), appressed after anthesis (usually) or spreading, 0.7–6.5 cm long. Rachis rounded in cross section or angular in cross section, trichomes over the entire surface. Spikelets evenly distributed along the branches; 2–6 on the longest branches; 6–12 mm long, 2.5–4.5 mm wide (male spikelets tending to be larger than female spikelets). Proliferating spikelets absent (not recorded for this taxon). Florets 2–3(–5). Glumes unequal (usually) or subequal, glabrous, margins not ciliate. First glume 3–5.5 mm long, veins 1. Second glume shorter than the first lemma, 4–6.5 mm long, veins 1–3. Rachilla internodes antrorsely scabrous (sparsely). Lemma callus not elongated. Lemma 4.5–8 mm long, with 5 distinct veins in dorsal view or nerveless in dorsal view or sometimes with only the centre vein distinct, with trichomes, trichomes over the entire surface (especially on the main vein); apex entire (keeled). Lemma awn absent (usually, sometimes present as a short mucro). Palea 4.4–7 mm long, distinctly pubescent between the keels. Lodicules with marginal teeth, glabrous or ciliate, 1.2–2.6 mm long. Anthers (2.5–)3.6–5 mm long. Ovary apex pubescent. Caryopsis 3.5–5 mm long.

Cytology. 2n = 56.

Habitat and Distribution. Native. Moist to dry grassland, rolling hills, open ridges or talus slopes to 11,000 feet. Northwestern USA: Oreg.; Southwestern USA: Calif., Nev.; Rocky Mountains USA: Colo., Idaho, Mont., Utah, Wyo.; North Central USA: Nebr.

Classification. Subg. Leucopoa (Griseb.) Hack. (subg. Hesperochloa, sect. Leucopoa (Griseb.) Krivot, Alexeev (1980)).


This taxon has separate female and male plants which has been used to justify treating it as a distinct subgenus or genus. No reason for placing the taxon in a separate genus has been found based on the analyses of this database (Aiken et al. 1997). The taxon is treated here as a Festuca based on INTKEY analyses of this database and the results of analyses of seed proteins using SDS-PAGE analyses. There have been discussions as to whether Cassidy ever saw the type of Watson's Poa kingii (S. J. Darbyshire, personal communication 1994).


• Line drawing. Illustration of F. kingii from Scribner (1901). Notes accompanying the illustration read, (a) Spikelets 3–5 flowered, 6–8 mm long with ovate-lanceolate, thin acute glumes. • Line drawing. Illustration in Piper (1906) as F. confinis Vasey. • Leaf anatomy. Leaf blades are 0.65–0.93–1.25 mm wide and 1.05–1.39–1.97 mm deep, data from 6 leaves of 4 specimens. There are 10–16 veins. Adaxial to abaxial sclerenchyma strands are present. Abaxial sclerenchyma strands are well developed, in broad bands or continuous. There are 10–16 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).