Festuca of North America

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

Festuca vallicola Rydb.

Nomenclature

Mem. N.Y. Bot. Gard. 1: 57. 1900. Type: Montana: Silver Bow, 9 July 1895, P.A. Rydberg 2108. Holotype: US! Three isotypes NY!

Considered a synonym of F. rubra in Hitchcock and Chase (1950).

Habit. Plants 50–60 cm high, not densely tufted, tiller bases not stiffly erect, horizontal rooting stems present (often short or absent from herbarium specimens). Vegetative shoots arising outside, or breaking through the base of existing sheaths.

Vegetative morphology. Sheaths with trichomes, not conspicuous at the base of the plant, splitting between the veins, open more than half their length (margins overlapping; F. rubra-like, retrorse hairs). Collars glabrous. Auricles absent. Ligules 0.1–0.3 mm long, ciliate. Leaf blades 5–10 cm long, more or less lax. Adaxial blade surfaces with trichomes, abaxial blade surfaces glabrous. Leaf blades plicate; 0.6–0.7 mm wide, 0.8–0.9 mm deep. Veins 5. Adaxial to abaxial sclerenchyma strands absent. Abaxial sclerenchyma poorly developed, in discrete, relatively narrow strands opposite the veins. Uppermost culm leaf sheaths not inflated. Flag leaf blades 3.5–8 cm long. Culm nodes becoming exposed, 1–2; internodes glabrous.

Floral morphology. Inflorescence 4–6 cm long. Inflorescence branches at the lowest node 1–3, appressed after anthesis, 0.5–2 cm long. Rachis angular in cross section, trichomes mainly on the ridges. Spikelets 10–12 mm long, 2–3 mm wide. Proliferating spikelets absent. Florets 5–7. Glumes unequal, with trichomes, vestiture at the apex only, margins ciliate. First glume 2.9–3.4(–4) mm long, veins 1. Second glume as long as the first lemma, or almost as long, 4–5(–6.5) mm long, veins 3. Rachilla internodes 1–1.5 mm long, antrorsely scabrous. Lemma callus not elongated. Lemma 5–6 mm long, with trichomes (scabrous), trichomes on the upper portion only; apex entire. Lemma awn 1–1.5 mm long. Palea 5–5.5 mm long, distinctly pubescent between the keels. Lodicules with marginal teeth, glabrous. Anthers 3.5–4.5 mm long. Ovary apex glabrous.

Habitat and Distribution. Native. Rocky Mountains USA: Mont.

Classification. Subg. Festuca L.

Notes

When F. vallicola was described, the author commented that it had generally gone under the name of F. rubra L., but he claimed, "it is distinct, at least from the Scandinavian plant. The latter quite often tufted, has larger spikelets, broader glumes, looser sheaths, broad flat stem leaves, and a much stouter stem. Festuca vallicola, so far as I know, never forms tufts or bunches and the innovations are few. I doubt if F. rubra is found at all in the Rocky Mountain region. All specimens so named which I have seen from the northern Rockies belong to the present species" (Rydberg 1900).

This treatment initially considered the taxon to be a North American endemic member of F. rubra s.l. found in moist habitats at relatively high altitudes in the Rocky Mountains. Close examination of the holotype and isotype material and cited specimens, suggests Rydberg had a mixed concept on which he based his description. Among the other specimens cited as being F. vallicola by Rydberg (1900), many are young and look superficially similar, but on more thorough examination there are at least two species, one F. rubra, the other possibly F. occidentalis Hook., as the ovary apex is densely hairy. Two of the cited specimens have sparse hairs on the ovary apex. It is possible that some of the cited specimens and the type are introduced members of the F. rubra complex, or possibly an isolated Rocky Mountain taxon, but this requires further study. The first author suggests that the type specimen from US and the three isotypes from NY may represent first year plants of F. rubra s.l. and that in this habitat they may be behaving as annuals, as first year plants are unable to survive freezing and thawing of the water in the habitat.

Illustrations

• Isotype specimen, NY. Isotype specimen from NY of F. vallicola. Right hand label reads: "F. rubra L. Locality Sliver Bow, Mont. Meadow. 2108 P.A. Rydberg, 8 July 1805". The delicate nature of the plants suggests they may be have been collected in the first year of growth. Isotype NY. • Isotype specimen, NY. Isotype specimen of F. vallicola from NY. Right hand label reads: F. rubra L. Locality Sliver Bow, Mont. Meadow. 2108 P.A. Rydberg, 8 July 1805. The delicate of the plants suggests they may be have been collected in the first year of growth. Isotype NY. • Holotype specimen, US. Holotype specimen of F. vallicola. Right hand label read: F. rubra L. Locality Sliver Bow, Mont. Meadow. 2108 P.A. Rydberg, 8 July 1805. The delicate of the plants suggests they may be have been collected in the first year of growth. Holotype US.


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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).

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