Festuca of North America

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

Festuca ligulata Swallen

Nomenclature

GUADALUPE FESCUE.

Am. J. Bot. 19: 436. 1932. Type: U.S.A. Texas: Culberson Co., Guadalupe Mountains, upper McKittrick Canyon, shaded moist slopes along creek, alt. 1980 m, 22 July 1931, J.A. Moore & J.A. Steyermark 3576. Holotype: US! Isotypes: GH! MO!

Habit. Plants bluish gray green, 45–80 cm high, densely tufted (Swallen 1932, described plants as "loosely tufted"), tiller bases stiffly erect, bases not purplish, horizontal rooting stems present (the base of the plant described as "decumbent, often rhizome-like" Swallen 1932, "often rhizomatous", Gould 1975. Rhizomes are not obvious on the holotype type or isotype specimens examined). Vegetative shoots arising from within existing sheaths (information supplied by Manuel Gonzalez 1989).

Vegetative morphology. Sheaths glabrous or with trichomes (minutely scaberulous), not conspicuous at the base of the plant, remaining entire, not conspicuously splitting between the veins, open more than half their length. Collars glabrous. Auricles represented by distinct, erect, swellings or absent (ligules conspicuous, decurrent). Auricular cilia absent. Ligules 3–4(–8) mm long (acuminate), ciliate (at apex). Leaf blades 6–35 cm long, erect, stiffish. Adaxial blade surfaces with trichomes (scabrous, with prominent veins), abaxial blade surfaces with trichomes (scabrous). Leaf blades flat or plicate (loosely rolled), 1–3 mm wide; 0.6–0.71–1 mm wide (when tightly rolled), 0.75–0.91–1.2 mm deep (based on 5 cross sections). Veins 5–7 (3 large, 2 or 4 small). Adaxial to abaxial sclerenchyma strands present, or absent (F. thurberi Vasey always has strands present). Abaxial sclerenchyma well developed, in discrete, relatively narrow strands opposite the veins. Ribs 7. Uppermost culm leaf sheaths not inflated. Flag leaf blades 5–7(–12) cm long. Culm nodes becoming exposed, 1–3; internodes scabrous-hirsute (scaberulous to scabrous near the panicle).

Floral morphology. Inflorescence 6–10(–16) cm long. Inflorescence branches at the lowest node 1–3, appressed after anthesis or spreading, 5–7 cm long. Rachis rounded in cross section or angular in cross section, trichomes mainly on the ridges or trichomes over the entire surface (scabrous). Spikelets aggregated towards the ends of the branches; 2–5 on the longest branches (spikelets distributed towards the ends of branches and tending to overlap); 6–8(–8.5) mm long, 1.5–2.5 mm wide. Proliferating spikelets absent. Florets 2–3. Glumes unequal (midveins prominent), with trichomes (scabrous), vestiture over most of the outer surface (scabrous), margins not ciliate (scabrous at the tips). First glume 2.8–4.1 mm long, veins 1. Second glume as long as the first lemma, or almost as long (or often slightly shorter), 3.5–5.5 mm long, veins 3. Rachilla internodes antrorsely scabrous. Lemma callus not elongated. Lemma 4.5–6 mm long, nerveless in dorsal view or sometimes with only the centre vein distinct, with trichomes, trichomes on the upper portion only; apex entire. Lemma awn absent. Palea 4–6 mm long (as long or slightly longer than the lemma), distinctly pubescent between the keels. Lodicules with marginal teeth, glabrous, 0.5–1.2 mm long. Anthers 1.5–2.6 mm long. Ovary apex pubescent. Caryopsis 3.2–3.5 mm long (the hilum about half as long as the grain).

Habitat and Distribution. Native. South Central USA: Tex. (endemic to western Texas, occurring in the higher mountains of the Trans-Pecos, below 2000 m on gentle moist and shaded pine-oak-juniper woodland slopes in semi-arid habitats with gravelly, sandy loams).

Classification. Subg. Leucopoa (Griseb.) Hack.

Notes

Swallen (1932) considered this species is "related to F. thurberi but differing in its less densely tufted habit, more slender culms, smaller panicles, fewer flowered spikelets and shorter obtuse lemmas". Analyses using this database, suggest that F. ligulata is not as closely related to F. thurberi as Swallen implied

Illustrations

• F. ligulata plant habit. Plant growing in Texas, Big Bend National Park. Photograph by Jackie Poole Texas Parks and Wildlife Department. • F. ligulata ligule. The junction of the leaf and leaf blade showing the relatively long ligule in this species. Plant growing in Texas, Big Bend National Park. Photograph by Jackie Poole Texas Parks and Wildlife Department. • F. ligulata inflorescence. Close up of inflorescence showing branches borne to one side of the rachis Plant growing in Texas, Big Bend National Park. Photograph by Jackie Poole Texas Parks and Wildlife Department. • Holotype specimen: US. Plants of F. ligulata collected in Texas, Culberson County, Guadalupe Mountains, in shaded moist slopes along creek, upper McKittrick Canyon. Alt. 1980 m, 22 July 1931, J.A. Moore and J.A. Steyermark. US 1501601. • Isotype specimen: GH. Plants of F. ligulata collected in Texas, Culberson County, Guadalupe Mountains, in shaded moist slopes along creek, upper McKittrick Canyon. Alt. 1980 m, 22 July 1931, J.A. Moore and J.A. Steyermark. GH. • Isotype specimen: MO. Plants of F. ligulata collected in Texas, Culberson County, Guadalupe Mountains, in shaded moist slopes along creek, upper McKittrick Canyon. Alt. 1980 m, 22 July 1931, J.A. Moore and J.A. Steyermark. MO 1011736. • Leaf anatomy. Leaf cross section of F. ligulata. Leaf blades are 0.6–0.71–1 mm wide, when tightly rolled and 0.75–0.91–1.2 mm deep, based on 5 cross sections. There are 5–7 veins, 3 large, 2 or 4 small. Adaxial to abaxial sclerenchyma strands are present, or absent, apparently differing from F. thurberi in this character but both conditions reported by Manuel Gonzalez, a student of Stephen Koch, who in 1989 had many herbarium specimens on loan for a thesis project and analyzed a DELTA character list. Abaxial sclerenchyma strands are well developed, in discrete, relatively narrow strands opposite the veins. There are 7 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).

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