| # Festuca of North America |

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

### Festuca hallii (Vasey) Piper

PLAINS ROUGH FESCUE.

Contrib. U. S. Natl. Herb. 10: 31. 1906. Melica hallii Vasey, Bot. Gaz. 6: 296. 1881. Daluca hallii (Vasey) Lunell, Am. Midl. Natl. 4: 221. 1915. F. altaica subsp. eu-altaica var. genuina subvar. hallii (Vasey) St.-Yves, Candollea 2: 271. 1925. F. scabrella Torrey in Hook. subsp. hallii (Piper) W.A. Weber, Univ. Colo. Stud., Ser. Biol. 7: 8. 1961. F. altaica subsp. hallii (Vasey) Harms, Madrono 32: 9. 1985. Type: U.S.A. Colorado: Rocky Mountains, northern half of the State, 1862, Hall 7 (= Hall & Harbour 621. US!)

F. confinis subsp. rabinosa Piper, Contrib. U.S. Natl. Herb. 10: 41. 1906. F. kingii var. rabinosa (Piper) Hitchc., Am. J. Bot. 21: 128. 1934. Hesperochloa kingii var. rabinosa (Piper) Swallen, Proc. Biol. Soc. Wash. 54: 45. 1941. Type: U.S.A. Wyoming: Branch Crazy Womans Cr., Alt. 8000 ft., with Stipa minor, 30 July 1898, Williams and Griffiths 25. Holotype: US!

Habit. Plants bluish gray green ("culms glabrous, often lustrous...blades mostly gray-green" Looman and Best 1979, p. 129), (18–)20–65(–85) cm high, densely tufted (but less so than in F. altaica; "somewhat rhizomatous and mat forming", Harms 1985), tiller bases stiffly erect, bases purplish (usually), horizontal rooting stems present (more or less well developed). Vegetative shoots arising from within existing sheaths.

Vegetative morphology. Sheaths glabrous (or minutely scaberulous at 40×), 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 scabrous or scaberulous trichomes on the veins, occur among the sheaths). Collars glabrous. Auricles represented by distinct, erect, swellings (usually). Auricular cilia absent. Ligules 0.3–0.6 mm long, ciliate. Leaf blades 10–35 cm long, erect, stiffish. Adaxial blade surfaces with trichomes, abaxial blade surfaces with trichomes (illustrated by Aiken and Lefkovitch, 1985, p. 1868 and image library). Leaf blades plicate; 0.4–0.78–1 mm wide, 0.7–0.98–1.25 mm deep. Veins 5–10. Adaxial to abaxial sclerenchyma strands present. Abaxial sclerenchyma well developed, in broad bands or continuous (often narrow). Ribs 5–8. Uppermost culm leaf sheaths not inflated. Flag leaf blades 1.5–3(–5) cm long. Culm nodes never exposed; internodes scabrous-hirsute (minutely scaberulous).

Floral morphology. Inflorescence 6–16 cm long. Inflorescence branches at the lowest node 1–2, appressed after anthesis ("open to contracted at anthesis", Looman and Best 1979, p.129), 2–4(–7) cm long. Rachis rounded in cross section or angular in cross section, trichomes over the entire surface. Spikelets aggregated towards the ends of the branches (with relatively few spikelets); 2–8 on the longest branches; 7–9.5 mm long (mostly green), 2–3.5 mm wide. Proliferating spikelets absent. Florets 2–3 (fertile, upper florets 0–2 sterile or with anthers only). Glumes subequal, glabrous, margins ciliate (boarder not conspicuously translucent). First glume (5–)6.5–8(–9.5) mm long, veins 1. Second glume as long as the first lemma, or almost as long (often longer than the first lemma), (6.2–)7–8.5(–9.5) mm long, veins 1–3. Rachilla internodes antrorsely scabrous. Lemma callus not elongated. Lemma 5.5–7(–9) mm long, nerveless in dorsal view or sometimes with only the centre vein distinct, with trichomes, trichomes over the entire surface; apex entire (illustrated by Pavlick and Looman, 1984, p. 1741). Lemma awn 0.5–1.3 mm long. Palea 5–6.5(–8.5) mm long (almost as long, or longer than the lemma), distinctly pubescent between the keels. Lodicules with marginal teeth or without marginal teeth, glabrous or ciliate, 0.9–1.1 mm long. Anthers 4–6 mm long. Ovary apex pubescent. Caryopsis 2.5–3.5 mm long.

Cytology. 2n = 28.

Habitat and distribution. Native; rangeland, prairie, dry habitats. Harms, 1985, stated that, "this rough fescue is a variant of the northern Great Plains grasslands and parklands (western Alberta, central Saskatchewan, to south eastern Manitoba and north western Dakota), apparently disjunct near Thunder Bay, Ontario, extending south along the eastern foothills of the Rocky Mountains in Montana and Wyoming to south central Colorado (in Colorado, at high elevations, rare and perhaps disjunct, as suggested by Weber, 1961". Canada: Ont., Man., Sask., Alta.; Northwestern USA: Wash.; Rocky Mountains USA: Colo., Mont., Wyo.; North Central USA: N. Dak.

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

Notes. Pavlick and Looman (1984), Alexeev (1985) and Aiken and Darbyshire (1990) treated this taxon as a full species. Harms (1985) suggested that this should be treated as F. altaica subsp. hallii (Vasey) Harms. The decision to continue to recognize this taxon as a full species rather than a subspecies is discussed in the notes for F. campestris Rydb.

Illustrations. • Plants in prairie habitat. Dominant grass is F. hallii growing in the Kernen prairie, near Saskatoon, Saskatchewan. Photograph by E. Hendrycks, Canadian Museum of Nature. • Fescue prairie habitat. Kernen prairie, near the town of Saskatoon, Saskatchewan, is approximately 5 acres of native prairie that has never been plowed. One of the dominant native grasses is Festuca hallii. Photograph by E. Hendrycks, Canadian Museum of Nature. • Leaf anatomy. Leaf cross section of F. hallii. Leaf blades are 0.4–0.78–1 mm wide and 0.7–0.98–1.25 mm deep, with 5–10 veins. Adaxial to abaxial sclerenchyma strands are present. Abaxial sclerenchyma strands are well developed, in broad bands or continuous, often narrow. There are 5–8 ribs. • Distribution map

We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations with detailed captions, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, and distributions of character states within any set of taxa. See also Guidelines for using data taken from Web publications.

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: 14th February 2019. delta-intkey.com’. Aiken, Dallwitz, McJannet, and Consaul (1997) should also be cited (see References).

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