Festuca of North America

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

Festuca washingtonica E. B. Alexeev

Nomenclature

Byull. Mosk. O-va Ispyt. Prir. Otd. Biol. 87: 115. 1982. Type: U.S.A. Washington: Pacific North West, Chelan County, Peavine Canyon, 3 June 1960, J.G. Smith. LE. Isotype WTU!

Habit. Plants deep green (bright green), (60–)70–80(–100) cm high, densely tufted (but tufts breaking into individual tillers), tiller bases stiffly erect, bases not purplish (or rarely purple), horizontal rooting stems absent. Vegetative shoots arising outside, or breaking through the base of existing sheaths.

Vegetative morphology. Sheaths glabrous or with trichomes (sometimes 0.4–0.7 mm long, fine and delicate, protruding at angles of 70–90 degrees from the sheath, older sheaths approaching scabrous), not conspicuous at the base of the plant, splitting between the veins or remaining entire, not conspicuously splitting between the veins (one some plants the sheaths are quite persistent and do shred, but do not become fibrillose and in F. rubra L.), closed more than half their length (young sheath observed to be closed almost to the collar). Collars glabrous, or villous (if villous, then similar to the leaf blade and sheath hairs). Auricles absent. Ligules 0.2–0.3(–0.5) mm long, ciliate. Leaf blades (13–)15–20(–35) cm long, erect, stiffish. Adaxial blade surfaces with trichomes (ca. 0.1 mm long), abaxial blade surfaces glabrous or with trichomes (scabrous on midvein and sclerenchyma strands, appearing shiny in fresh material). Leaf blades flat (when fresh) or plicate (after drying: both conditions illustrated by Alexeev 1982), 2–3 mm wide; 0.9–1 mm wide, 0.9–1 mm deep. Veins 7–9. Adaxial to abaxial sclerenchyma strands present (rarely), or absent (but commonly with sclerenchyma on the tops of the ribs adjacent to the main lateral bundles). Abaxial sclerenchyma well developed, in broad bands or continuous (some strands heavily thickened, others relatively narrow). Ribs 7 (well defined). Uppermost culm leaf sheaths somewhat inflated (usually). Flag leaf blades 8.5–17 cm long. Culm nodes becoming exposed, 1–2; internodes glabrous.

Floral morphology. Inflorescence 10–15 cm long. Inflorescence branches at the lowest node 1 or 2, appressed after anthesis, 0.5–4(–6) 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; 2–8 on the longest branches; 9.5–15(–18) mm long, 1.5–2.5 mm wide. Proliferating spikelets absent. Florets (3–)5–8(–10). Glumes unequal, with trichomes, vestiture at the apex only (scaberulous), margins ciliate. First glume (3.5–)4–5.5 mm long, veins 1. Second glume shorter than the first lemma, 5.5–7 mm long, veins 3. Rachilla internodes 0.9–1.5 mm long. Lemma callus not elongated. Lemma (6.5–)7–9(–11) mm long. Lemma awn 1.5–3.5 mm long (-4). Palea 6–7 mm long, distinctly pubescent between the keels. Lodicules with marginal teeth, glabrous, 1–1.5 mm long. Anthers 3–4 mm long (-4.7 mm: pre-anthesis anther 2.7 mm). Ovary apex pubescent.

Habitat and Distribution. Native. Semi-arid shrub-steppe. Northwestern USA: Wash.

Classification. Subg. Festuca L.

Notes

Described as a new species by Alexeev (1982) but not widely taken up. The specimens examined by the first author and SDS-PAGE analyses of seed proteins confirm that this is a distinct species.

When Alexeev (1982) recognized this taxon, he commented, that "in habit and anatomical structure of the leaf blades, this species resembles F. rubra. However, within the limits of the very polymorphous latter species, we do not know of a single taxon with leaf blades that are externally scabrous, as in F. washingtonica, which has trichomes up to 0.08 mm long." Alexeev (1982) cited as the type specimen, a plant that had been collected on 3 June 1960 and he described the ovary apex as glabrous. Alexeev appears to have examined only one specimen and that of a plant collected so early in the growing season that the ovaries were too small to have developed apical hairs.

Specimens of this taxon may sometimes have been labelled F. viridula Vasey or F. rubra. (Specimens examined: the isotype, and specimens from U.S.A. Washington: Benton Co., growing in a narrow strip just below the tip of Rattlesnake Mountain in the snowmelt zone, in rocky silt loan, with Artemisia tridentata, Lupinus laxiflorus var. calcaratus, Poa nevadensis, Senecio integerrimus, Festuca idahoensis, Melica bulbosa and Poa cusickii, elevation 3400 feet, 4 June 1995, (and from the same site later in the season) Kathryn Beck & Florence Caplow 95088).

Hitchcock et al. (1969) when discussing F. viridula commented on the "marcescent fibrous veins of the sheaths". This is a characteristic of F. washingtonica which has closed sheaths; those in F. viridula are open. The concept of F. viridula in Hitchcock et al. (1969) may have covered both taxa. Festuca washingtonica differs from F. viridula in having closed sheaths, extravaginal shoots, and abaxial to adaxial sclerenchyma strands in the leaves, illustrated by Alexeev (1982). Both species have mature ovaries with dense hairs at the apex.

Illustrations

• 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).

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