Festuca of North America


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

Festuca calligera (Piper) Rydb.


Bull. Torrey Bot. Club 36: 537. 1909. F. ovina subsp. calligera Piper, Contrib. U.S. Natl. Herb. 10: 27. 1906. F. amethystina var. asperrima Hack. ex Beal, Grasses N. Am. 2: 601. 1896. Type: U.S.A. Arizona: Flagstaff, 1883, H.H. Rusby 901. Holotype: US! Isotypes: GH! NY!

Habit. Plants bluish gray green, 30–65 cm high, densely tufted (tussocks very compact; no prophylls found), tiller bases stiffly erect, bases not purplish (or rarely purplish), horizontal rooting stems absent. Vegetative shoots arising from within existing sheaths.

Vegetative morphology. Sheaths glabrous or with trichomes (that are retrorse hairs, and sometimes minute), not conspicuous at the base of the plant (cf. F. arizonica Vasey which has conspicuous sheaths), remaining entire, not conspicuously splitting between the veins, open more than half their length. Collars glabrous. Auricles represented by distinct, erect, swellings. Auricular cilia absent. Ligules 0.2–0.3 mm long, ciliate. Leaf blades 6–12 cm long, erect, stiffish. Adaxial blade surfaces with trichomes (sparsely, antrorsely scabrous), abaxial blade surfaces with trichomes. Leaf blades plicate; 0.25–0.41–0.5 mm wide, 0.4–0.5–0.65 mm deep. Veins (3–)5. Adaxial to abaxial sclerenchyma strands absent. Abaxial sclerenchyma well developed, in broad bands or continuous (often heavily thickened - somewhat like F. arizonica). Ribs 1 (well defined central rib, 2–4 variously defined lateral ribs). Uppermost culm leaf sheaths not inflated. Flag leaf blades 3–5.5 cm long. Culm nodes becoming exposed, 1; internodes glabrous.

Floral morphology. Inflorescence 5–9(–15) cm long. Inflorescence branches at the lowest node 1–2, appressed after anthesis, 2–6(–10) cm long. Rachis angular in cross section, trichomes mainly on the ridges. Spikelets loosely scattered in an open panicle with slender branches; 1–4 on the longest branches; 6–8.5(–11) mm long, 2–3.5 mm wide. Proliferating spikelets absent (not recorded for this taxon). Florets 2–6. Glumes unequal, with trichomes, vestiture at the apex only, margins ciliate. First glume 2.5–3.5 mm long, veins 1. Second glume shorter than the first lemma, 2.8–4 mm long, veins 3. Rachilla internodes glabrous, or nearly so. Lemma callus not elongated (but a distinct knob at the base of the lemma). Lemma 3.8–5.2 mm long, nerveless in dorsal view or sometimes with only the centre vein distinct, with trichomes, trichomes on the upper portion only (scaberulous); apex entire. Lemma awn 1–2.5 mm long. Palea 4–5 mm long, distinctly pubescent between the keels. Lodicules with marginal teeth, glabrous, 0.8–1 mm long. Anthers 2.2–3.3 mm long. Ovary apex pubescent (sparsely; cf. F. arizonica which has a densely pubescent ovary apex and F. idahoensis Elmer which has a glabrous ovary). Caryopsis 2.5–3 mm long.

Cytology. 2n = 28 (unpublished counts by J.R. Reeder 1996. He obtained the same chromosome number from several samples and saw no meiotic irregularities).

Habitat and Distribution. Native; alpine, or rangeland, prairie, dry habitats. Southwestern USA: Ariz. (occurring at and above 2800 m, in north-eastern Arizona, field observations made by C.-E. Granfelt, 1993–1996); Rocky Mountains USA: Colo., Utah, Wyo.; South Central USA: N. Mex.

Classification. Subg. Festuca L.


Festuca calligera has been compared with F. arizonica and F. idahoensis and assessed as a possible hybrid between them, following the suggestion of Cronquist et al. (1977) that the latter two taxa may intergrade. The leaf anatomy in cross sections and the distribution maps of the taxa, mapped in this database, lend support to this idea. Plants of F. arizonica have ovaries with a densely hairy apex, F. idahoensis plants have ovaries with a glabrous apex, and F. calligera specimens have ovaries with a few sparse hairs at the apex, similar to the ovary apex for F. minutiflora Rydb. (Frederiksen 1979, illustrated in the image library under F. minutiflora). Hairs are absent in the early stages of development, when the ovaries are less than 1 mm high and without the styles completely separated at the base. Many samples have been collected at early stages of development. Pollen fertility has been examined in two anthers of approximately 10 specimens of F. calligera and anthers with 90–100% stainable pollen were found. Approximately 10 grams of well formed seeds were collected by C.-E. Granfelt at two sites in Northern Arizona. The seeds of F. calligera are conspicuously smaller than the seeds of F. arizonica received from the same general locality.

In 1993 and 1994, Carl-Eric Granfelt made collections of both F. arizonica and F. calligera from above 2800 m on the White Mountains and Escudilla Mountain of north eastern Arizona. Specimens (deposited at CAN) are sometimes similar in height but the bases of the plants are strikingly different as F. arizonica has conspicuous, persisting sheaths and usually leaves more than twice as long as adjacent plants of F. calligera. In the latter species the sheaths are not conspicuous and the culms below the inflorescences are glabrous.

Festuca arizonica and F. calligera grow in the same grassland association, sometimes within a metre of each other (illustrated in the image library). They do not appear to hybridize, possibly because F. arizonica flowers later than F. calligera (C-E. Granfelt, Pinetop Arizona, personal observations, 1993–1996). Awn length in specimens of F. arizonica varies from 0.4–2(-2.7) mm long, and in F. calligera from 1–2.5 mm. No basis for separating the "long-awned forms" of F. arizonica, referred to by Cronquist et al. (1977), has been found.

Festuca calligera appears to occur in the south-western United States at altitudes above 2800 m. Many of the herbarium specimens have been collected at early stages of flowering and in such collections, floral characters are more difficult to interpret. Aldon and Barstad (1987) listed F. ovina as occurring in the Escudilla study site and voucher specimens for the name used were checked and are considered to be plants of F. calligera. This species appears to have been under collected and generally overlooked. (Also see notes for F. arizonica).


• Plant habit. Left, small photograph showing yellow green plants of F. arizonica (in the distance) growing in the same area as bluish green, shorter plants of plants of F. calligera (foreground), on Gillespie Flat, Apache Co., Arizona. Photograph by C-E. Granfelt, 21 July 1994. Centre, close up of F. arizonica; Right, close up of F. calligera. • Holotype specimen: US. Holotype specimen collected in Arizona. The picture is from a photocopy of the herbarium specimen. The left label reads, "renamed F. ovina calligera by Piper because of F. asperrima Link under present rules would be F. ovina asperrima Hack". Above the right label is a note which reads, "This is the type of F. amethystina var. asperrima Hack. Beal Grasses N. Am. 2: 601 as there is no specimen of this number in Herb. Beal. C.V.P. (Piper)". The right label reads "Herb. United States Department of Agriculture. F. amethystina var. asperrima Hack. 901. Locality Arizona. Collector H.H. Rusby 1883". • Isotype specimen: GH. Isotype specimen. The label reads, "Herbarium of Woodbury P. Conant, one-time Assistant to George Vasey. Transferred from Peabody Museum, Salem, 1942. Flora of Arizona. No. 901. Festuca ovina L. var., Flagstaff. Leg. H.H. Rusby, July 1883". Annotated by C.A. Taylor Jr. Aug. 27 1947 as "Isotype of Festuca amethystina var. asperrima Hack. ex Beal.". • Topotype specimen: NAU. Topotype specimen collected from Flagstaff, Arizona. • Leaf anatomy. Leaf cross section of F. calligera. Leaf blades 6–12 cm long, erect, stiffish; adaxial blade surfaces with sparse, antrorsely scarbrous trichomes. Leaf cross sections are 0.25–0.41–0.5 mm wide and 0.4–0.5–0.65 mm deep, with (3-)5 veins. Adaxial to abaxial sclerenchyma strands are absent. Abaxial sclerenchyma strands are well developed, in broad bands or continuous, often heavily thickened - somewhat like F. arizonica. There is one well defined central rib and 2–4 variously defined lateral 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).