| # Festuca of North America |

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

### Festuca saximontana Rydb. subsp. saximontana

ROCKY MOUNTAIN FESCUE.

Bull. Torrey Bot. Club 36: 536. 1909. F. ovina subsp. saximontana (Rydb.) St.-Yves, Candollea 2: 245. 1925. F. ovina subsp. saximontana var. rydbergii St.-Yves, Candollea 2: 245. 1925. F. brachyphylla subsp. saximontana (Rydb.) Hultén, Fl. Alaska and Yukon 2: 242. 1942. F. ovina var. saximontana (Rydb.) Gleason, Phytologia 4: 21. 1952. F. brachyphylla var. rydbergii (St.-Yves) Cronquist, in Man. Vasc. Pl. Gleason and Cronquist, 749. 1991. Type: Canada. Alberta: Rocky Mountains, in the vicinity of Banff, side of road, Mountain Avenue, 4600 feet, 28 July 1899, W.C. McCalla 2331. Holotype: NY! Isotypes: K, US!

F. canadensis E. B. Alexeev, Byull. Mosk. O-va Ispyt. Prir. Otd. Biol. 88: 104. 1983. Type: Canada. Ontario: comté de Simcoe, Wasaga Beach, sur les dunes de la Baie Georgienne, 12 July 1936, F. Marie-Victorin, F. Rolland-Germain & F. Dominique 46144. (Translated, Canada. Ontario: Simcoe County, Wasaga Beach, on the sand dunes of Georgian Bay, 12 July 1936, F. Marie-Victorin, F. Rolland-Germain, F. Dominique 46144.) Holotype: LE. Isotype: DAO!

F. saximontana Rydb. var. robertsiana Pavlick, Can. J. Bot. 62: 2452. 1984. Type: Canada. British Columbia: Taseko Mt. (Chilcotin), Pavlick 81–178. Holotype: V.

F. ovina subsp. pseudovina sensu Piper, Contrib. U.S. Natl. Herb. 10: 27. 1906, quoad. pl. cit. non F. pseudovina Hack. ex Weisb.

Habit. Plants bluish gray green or deep green, (5–)20–50(–60) cm high, densely tufted, tiller bases stiffly erect, bases not purplish, horizontal rooting stems absent. Vegetative shoots arising from within existing sheaths.

Vegetative morphology. Sheaths glabrous or glabrescent (sometimes with minute retrorse pubescence), 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 (fused to one third of their length, Frederiksen (1983); prophylls 1–2.5 cm long, delicate, with glabrescent keels). Collars glabrous. Auricles represented by distinct, erect, swellings. Auricular cilia absent. Ligules 0.1–0.4 mm long, ciliate. Leaf blades 2–20 cm long, erect, stiffish. Adaxial blade surfaces with trichomes, abaxial blade surfaces glabrous or with trichomes (antrorsely, at least toward the apex; one specimen with long leaves, growing in a meadow in Utah had small trichomes developed on the abaxial surface of leaves. Voucher: Utah, Garfield Co., 5 mi. east of Widstoe, meadow, yellow pine, spruce forest, 4 August 1954, B.P. Harrison 12334. NY). Leaf blades plicate; 0.3–0.45–0.7 mm wide, 0.5–0.72–0.9 mm deep. Veins 5–8. Adaxial to abaxial sclerenchyma strands absent. Abaxial sclerenchyma well developed, in broad bands or continuous (rarely). Ribs 1 (well defined, 2 poorly defined). Uppermost culm leaf sheaths not inflated. Flag leaf blades 0.5–4 cm long. Culm nodes becoming exposed, 1–2; internodes glabrous.

Floral morphology. Inflorescence 3–9(–13) cm long. Inflorescence branches at the lowest node 1–2, appressed after anthesis, 0.5–3(–5) cm long. Rachis angular in cross section, trichomes mainly on the ridges or trichomes over the entire surface. Spikelets aggregated towards the ends of the branches (or evenly distributed on short branches, that are usually appressed to the rachis); 1–4 on the longest branches; (3.5–)4.5–9(–10) mm long, 1.5–3(–4) mm wide. Proliferating spikelets absent (usually, recorded rarely, e.g. DAO 228637). Florets (2–)3–4(–6). Glumes unequal, with trichomes, vestiture at the apex only (and along midvein), margins ciliate. First glume 1.5–3.5 mm long, veins 1. Second glume shorter than the first lemma, 2.5–4.8 mm long, veins 3. Rachilla internodes 0.9–1.1 mm long, antrorsely scabrous. Lemma callus not elongated. Lemma 3–5.6 mm long, nerveless in dorsal view or sometimes with only the centre vein distinct, glabrous or with trichomes, trichomes on the upper portion only; apex entire. Lemma awn 0.5–2(–2.5) mm long. Palea 3–5 mm long, distinctly pubescent between the keels. Lodicules with marginal teeth, glabrous, 0.5–0.7 mm long. Anthers (0.9–)1.2–1.7(–2.1) mm long (sometimes as small as 0.9 mm in Oregon specimens, B.L. Wilson, personal communication 1995). Ovary apex glabrous. Caryopsis 2.2–2.8 mm long.

Cytology. 2n = 42.

Habitat and distribution. Native; alpine and rangeland, prairie, dry habitats. Greenland; Canada: Labrador, Nfld., Que., Ont., Man., Sask., Alta., B.C., Mackenzie District (NWT), Yukon; Northwestern USA: Alaska, Oreg., Wash.; Southwestern USA: Ariz., Calif., Nev.; Rocky Mountains USA: Colo., Idaho, Mont., Utah, Wyo.; North Central USA: Kansas, Minn., N. Dak., S. Dak., Wis.; South Central USA: N. Mex.; Northeastern USA: Mich.

Classification. Subg. Festuca L.

Notes. Whether distinctions between Festuca brachyphylla Schult. & Schult. f. and F. saximontana deserve species status has been debated. Hultén (1942) reduced the taxon to F. brachyphylla subsp. saximontana based on anther length, but Hultén (1968) recognized the taxon as a full species. Frederiksen (1982) stressed that F. saximontana deviates from F. brachyphylla and related taxa in having strongly developed sclerenchyma in the leaf blades and anthers normally longer than 1.2 mm. Gleason and Cronquist (1991) treated F. saximontana with varietal status as F. brachyphylla var. rydbergii (St.-Yves) Cronquist. This was on the basis that Cronquist could not see a difference between the taxa (personal communication 1990).

On the NY type specimen of F. saximontana, W.A. Weber of the University of Colorado Museum, Boulder, Colorado, 9 November 1966, wrote, "Hultén (1942) reduced this to subspecific rank under F. brachyphylla Schultes. Holmen (1964) showed that the type (this specimen) has long anthers and hence could not belong to F. brachyphylla but showed some close affinity to the Eurasian F. trachyphylla.

Although I can not vouch for the separation of F. saximontana from F. trachyphylla, I support Holmen's contention that F. saximontana has little in common with F. brachyphylla and for the time being I feel should be maintained at specific rank. The following diagnostic key serves to distinguish the two.

Anthers 1.0–1.5 mm long; leaves glaucous; culms tall, about 2 to 3 times the height of the basal leaves; ligule conspicuous, 0.3 mm long; lemma 6.0–7.5 mm. long inclusive of the awn; plants of lower and middle foothill to subalpine. ...F. saximontana

Anthers 0.7–0.8 mm long; leaves green; culms usually less than twice the height of the basal leaves; ligule minute or obsolete; lemma 3–4 mm long inclusive of the awn. ..F. brachyphylla.

In addition to the characters cited above, the more extensive sclerenchyma development in the leaves of saximontana, mentioned by Holmen, give the blades a rigidity and resistance to crumpling which sets is apart from brachyphylla. In brachyphylla the leaves are more often collapsed between the nerves and easily folded or crumpled."

Although the two species are normally quite distinct, some early season collections may be difficult to determine. In the northern areas of the range of F. saximontana, there are specimens that have been collected with the characters: anther lengths, leaf dimensions in cross sections, and sclerenchyma development, that overlap with F. brachyphylla subsp. brachyphylla (locations for example in St. Elias Mountains, southwest Yukon; Great Bear Lake, N.W.T. and James Bay, Ontario and Quebec). Larger specimens of F. brachyphylla subsp. brachyphylla, may grow up to 55 cm tall in lush conditions, a height more common in plants of F. saximontana. When there are limited habitat data on herbarium labels, identification often is a challenge.

In a study of candidate specimens to confirm the record of F. saximontana on Baffin Island, N.W.T., the first author concluded that the single specimen recorded from Iqaluit, Baffin Island, N.W.T. (annotated by S. Frederiksen, housed at CAN and mapped by Aiken and Darbyshire 1990) is a tall specimen of F. brachyphylla. This species is sensitive to nitrogen loads randomly applied in microhabitats and which may result in plants twice the size of an adjacent "typical" F. brachyphylla. Isozyme studies and SDS-PAGE of the seed proteins have failed to produce evidence that F. saximontana occurs in the Canadian Arctic Archipelago (Aiken et al. 1992, 1993, and 1995). Data on herbarium labels and field observations suggests that taller plants of F. saximontana occur at lower elevations and in more sheltered habitats. The development of purple coloration in spikelets, of this taxon and others in the genus, is often associated with exposed alpine or arctic habitats. An albino form of F. saximontana has been observed, but this has not been taxonomically recognized (cf. F. brachyphylla forma flavida Polunin).

In studying the leaf anatomy, Aiken and Consaul (1995) found that in F. saximontana the sclerenchyma is in broad bands, that are sometimes almost continuous. Rarely the sclerenchyma is reduced to three bands at the midrib and leaf margins, such that the leaf cross sections looks superficially like F. lenensis Drobow or F. valesiaca Schleicher ex Gaud. Leaf cross sections with only three bands of sclerenchyma were observed among specimens collected towards the southern end of the distribution range of F. saximontana in the United States.

Illustrations. • Flowering plant. Garden grown plant of F. saximontana subsp. saximontana with inflorescences at anthesis. The plants were collected in Alberta in 1980, grown at the Agriculture Canada Experimental Farm, Ottawa, Ontario for many years and later transferred to a private garden in Ottawa, where they have continued to thrive and spread by seed. • Inflorescences. Close up of the inflorescence of the previous plant of F. saximontana subsp. saximontana with numerous spikelets at anthesis. • Leaf anatomy. Leaf cross section of F. saximontana subsp. saximontana. Leaf blades are 0.3–0.45–0.7 mm wide and 0.5–0.72–0.9 mm deep, with 5–8 veins. Adaxial to abaxial sclerenchyma strands are absent. Abaxial sclerenchyma are well developed, in broad bands or continuous (rarely). There is one well defined rib and 2 poorly defined ribs. • Habitat in Utah Uinta National Forest. Festuca saximontana grows as small tufted plants, closely associated with the blue green sage plants and is found in the same habitat as F. dasyclada, the larger browner grasses (white box, lower left). • Holotype: NY. Original label reads, "Plants of the Northern Rocky Mountains. Collected in the vicinity of Banff, Alberta, Canada by W.C. McCalla 2331. Festuca saximontana. Side of road. Mountain Avenue. Alt. 2600 ft. July 28th 1899.". • 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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