| # Festuca of North America |

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

### Festuca paradoxa Desv.

CLUSTER FESCUE.

Opusc. Sci. Phys. Nat.: 105. 1831. Type: U.S.A. Habitat unknown. Holotype: ?

F. nutans Biehler, Pl. Nov. Herb. Spreng. Cent.: 10. 1807, non Moench, Meth. Fl. 191. 1794. Poa nutans (Biehler) Link, Enum. Pl. 1: 86. 1821. Gnomonia nutans (Biehler) Lunell, Am. Midl. Natl. 4: 224. 1915. Type: Pennsylvania. Muhlenberg.

F. shortii Kunth ex Wood, Class-book ed. 3: 794. 1861. F. nutans var. shortii (Kunth ex Wood) Beal, Grasses N. Am. 2: 589. 1896. Piper (1906) stated, "No locality cited under the original very brief description, but a specimen in Short's herbarium bears the legion, 'Barrens of Meade County, Kentucky.'" Holotype: PH! Isotypes: GH! WIS!

F. nutans var. major Vasey, U.S. Dept. Agric. Spec. Rpt. 63: 43. 1883, nom. nud.

Habit. Plants yellowish green (light green), 50–120 cm high, not densely tufted (leaves mainly on the culms), tiller bases stiffly erect, bases not purplish, horizontal rooting stems absent. Vegetative shoots arising outside, or breaking through the base of existing sheaths.

Vegetative morphology. Sheaths glabrous or with trichomes, not conspicuous at the base of the plant, splitting between the veins, open more than half their length. Collars glabrous. Auricles absent (Piper 1906 stated "auriculate at the base", but no true auricles have been found). Ligules 0.2–1 mm long, ciliate. Leaf blades 10–40 cm long, more or less lax. Adaxial blade surfaces glabrous or with trichomes, abaxial blade surfaces glabrous. Leaf blades flat, 2–8 mm wide. Veins 9–30. Adaxial to abaxial sclerenchyma strands present. Abaxial sclerenchyma poorly developed, in discrete, relatively narrow strands opposite the veins (with prominent bulliform cells between the ribs). Uppermost culm leaf sheaths not inflated. Flag leaf blades 10–30 cm long. Culm nodes becoming exposed, (2–)3(–4); internodes glabrous.

Floral morphology. Inflorescence 5–20 cm long. Inflorescence branches at the lowest node 2 (usually, rarely 3–5), appressed after anthesis (but early in development drooping from the weight of clustered spikelets, not reflexed at maturity), 3–10 cm long. Rachis angular in cross section, trichomes mainly on the ridges (prominent) or trichomes over the entire surface (sparse). Spikelets aggregated towards the ends of the branches (overlapping each other by one third to one half their length on the lower branches); 10–30 on the longest branches; 5–7 mm long (oblong lanceolate), (2–)4–4.5(–6) mm wide (clavate in bud). Proliferating spikelets absent (usually, two specimens collected in Missouri, herbarium of Ceo. V. Nash at NY! and MO 341986). Florets (2–)4–5(–10). Glumes unequal, with trichomes (varying from scabrous to scaberulous), vestiture over most of the outer surface (at least on the midvein), margins not ciliate. First glume 2.5–5 mm long, veins 1. Second glume as long as the first lemma, or almost as long, 3.5–5.5 mm long, veins 3. Rachilla internodes glabrous, or nearly so. Lemma callus not elongated. Lemma (3.6–)4–5(–5.2) mm long (coriaceous), nerveless in dorsal view or sometimes with only the centre vein distinct, with trichomes, trichomes over the entire surface (varying from scaberulous to scabrous); apex entire (but often splitting at the pronounced midvein). Lemma awn absent (mucronate). Lemma and palea not becoming indurate (sometimes approaching indurate). Palea 3.5–4.5 mm long, distinctly pubescent between the keels (at apex) or glabrous between the keels. Lodicules without marginal teeth, glabrous, 0.7–0.8 mm long. Anthers 1.1–1.5 mm long. Ovary apex pubescent. Caryopsis 2–3 mm long.

Cytology. 2n = unknown.

Habitat and distribution. Native. North Central USA: Iowa, Ill., Kansas, Mo., Okla., Wis.; South Central USA: Tex.; Northeastern USA: Pa.; Southeastern USA: Ala., Ark., Del., Ga., Ky., Miss, N.C., S.C., Tenn., Va.

Classification. Subg. Subulatae (Tzvelev) E. B. Alexeev, sect. Obtusae E. B. Alexeev.

Notes. The taxonomic rank of this species was reconsidered by Aiken and Lefkovitch (1993) after the suggestion by Gould (1975) that this taxon may be merely a subspecies of F. subverticillata (Pers.) E. B. Alexeev. The former authors concluded that phenotypic plasticity results in northern specimens of F. paradoxa often having small spikelets and morphological measurements that fall within the traditional ranges of characters of F. subverticillata. Branches of pre-anthesis inflorescences of F. subverticillata can have a wide range of lengths and are often drooping and clustering during some stages of development. In the southern part of the distribution range, their spikelets can become similar in size to some of those of F. paradoxa. Characters often found in published keys, that were found to overlap in values, are: (a) length of the longest inflorescence branch, (b) number of spikelets per branch, and (c) spikelet width.

The following distinguishing attributes are considered more reliable.

Inflorescence branches not reflexed at maturity; spikelets clustered, consistently overlapping each other by 1/3 to 1/2 their length on the lower branches; spikelets clavate in bud; upper glume almost as long as or longer than the first lemma.... F. paradoxa

Inflorescence branches reflexed at maturity; spikelets often widely separated on the lower branches, sometimes overlapping slightly towards the ends of the branches; spikelets lanceolate in bud; upper glume usually shorter than the first lemma.... F. subverticillata

Illustrations. • Habitat and close up of plant. Habitat and close up of a plant of F. paradoxa. Main picture, Margaret Magai is holding an inflorescence of pre-anthesis cluster fescue. Inset, a close up of the inflorescence showing clustered and drooping arrangement of spikelets. Later in the growing season, when caryopses have developed making the inflorescence heavier, this is more pronounced. • Isotype specimen: GH. Type specimen of F. paradoxa. Label on bottom left hand corner reads, "Festuca pratensis? nutans. Barrens of Ky apparently native! C.W. Short M.D., Kentucky, 1842." Isotype GH. • 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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