Eriocoma valdesii Hoge ex Romasch., P.M. Peterson & Soreng, 2020

Peterson, Paul M., Romaschenko, Konstantin, Soreng, Robert J. & Valdes Reyna, Jesus, 2020, Eriocoma valdesii, a new species from Mexico (Poaceae, Stipeae), PhytoKeys 139, pp. 21-28 : 21

Eriocoma valdesii Hoge ex Romasch., P.M. Peterson & Soreng sp. nov. Fig. 1A-M

Type.

México, Coahuila, Municipio de Saltillo, 2 km above Estación Carneros just below microondas [25.12306N, 101.11828W], 2270 m, 13 Sep 2012, Peterson, Romaschenko & Valdés Reyna 24469 (holotype: US-3741901!; isotypes: ANSM!, US-3741902!).

Diagnosis.

Differing from Eriocoma lobata (Swallen) Romasch. in having ligules (2-) 4.5-8.5 mm long with acute to narrowly acute and lacerate apices (verses ligules ≤ 1.5 mm long with truncate apices) and florets with a sharp-pointed callus (verses florets with a blunt callus) [ Swallen 1933; Barkworth 2007; Valdés Reyna 2015].

Description.

Perennials, cespitose, without rhizomes. Culms 60-130 cm tall, erect, unbranched above, 2-4 mm in diameter near the base, nodes 3-4 below the inflorescence, glabrous. Leaf sheaths shorter than the internodes, glabrous, older ones dorsally flattened below; collar glabrous or sparsely pubescent; ligules (2-) 4.5-8.5 mm long, strongly asymmetrical, membranous, margins decurrent, often with small hairs above, the hairs less than 1 mm long, apex acute to narrowly acute, lacerate; blades (15-) 25-50 (-60) cm long, (2-) 3-5 mm wide, flat to involute, glabrous, smooth below, scabrous above and along margins. Panicles 12-35 cm long, 1-2 cm wide, narrow and contracted; branches 1-6.5 cm long, ascending, straight and tightly appressed. Spikelets 8-13 mm long, usually lanceolate, subterete, rarely laterally compressed, with one fertile floret without rachilla extension, disarticulation above the glumes; glumes 8-13 mm long, longer than the florets, membranous, mostly hyaline above, 3-veined, unawned, apex long acuminate; lower glumes 10-13 mm long; upper glumes 8-12 mm long; florets (including the callus) 6-7.5 mm long, terete, fusiform, straminious to light brownish; callus about 1-1.4 mm long, densely bearded with hairs up to 1.5 mm long, the base sharp-pointed and slightly curved; lemmas coriaceous, indurate, evenly hairy, the hairs 1-1.4 (-2) mm long, apex 2-lobed, the lobes about 0.2-0.5 mm long; lemmatal awns 12-24 mm long, 1 or 2-geniculate, the lowest one or two segments twisted and short hairy (sometimes only visible in young material), the hairs less than 1 mm long, upper segment scabrous; paleas 3.2-5 mm long, shorter than the lemma, hairy, 2-veined, veins not prolonged; stamens 3, anthers (2.6-) 3-3.3 mm long, dehiscent, penicillate; lodicules 2 or 3, about 1.2-1.5 mm long, narrow-elliptic; stigmas 2. Caryopses 4-6 mm long, fusiform, pericarp adherent, hilum linear.

Distribution.

The new species is known from the Municipio de Bustamante in Tamaulipas, the Municipio Catorce in San Luis Potosí, the Municipio de Saltillo in Coahuila, and the Municipios Galeana and Santa Catarina in Nuevo León.

Conservation status.

The species is rare in México, but with more collecting it probably will be found in the adjacent state of Zacatecas.

Etymology.

The specific epithet honors Jesus Valdés Reyna (1948-), a renowned Mexican agrostologist, friend, and colleague who PMP, RJS, and KR have worked with for more than 35 years.

Ecology.

The new species has been found on calcareous (gypsum) rocky slopes and hillsides at 1700-2721 m associated with Pinus cembroides Zucc, P. teocote Schltdl. & Cham., Juniperus coahuilensis ( Martínez) Gaussen ex R.P. Adams, Quercus pringlei Seemen, Cowania mexicana D. Don, Rhus virens Lindh. ex A. Gray, Parthenium incanum Kunth. Arctostaphylos pungens Kunth, Arbutus xalapensis Kunth, Buddleja tomentella Standl., Bauhinia ramossisima Benth. ex Hemsl., Cercocarpus betuloides Nutt., Yucca carnerosana (Trel.) McKelvey, Agave lechuguilla Torr., A. gentryi B. Ullrich, Mimosa biuncifera Benth., Eriocoma lobata , Muhlenbergia , dubia E. Fourn., M. pubescens (Kunth) Hitchc., Pseudoeriocoma multinodis (Scribn. ex Beal) Romasch., Erioneuron avenaceum (Kunth) Tateoka, Aristida curtifolia E. Fourn., Bouteloua uniflora Vasey, Berberis sp., Brickellia sp., Prunus sp., Salvia , spp., Stevia sp., Tagetes sp., Dasylirion sp., Ephedra sp., Brahea sp., and Heliotropium sp.

Discussion.

Another species morphologically similar to E. valdesii in having sharp-pointed calluses, although not yet collected in México, is E. scribneri (Vasey) Romasch. found in the USA in western Texas, New México, Arizona, Colorado, Utah, and southeastern Wyoming ( Barkworth 2007). However, E. scribneri differs in having shorter ligules ≤ 1.5 mm long with truncate apices and paleas 2.5-3.5 mm long (verses paleas 4-5 mm long in E. valdesii ). Eriocoma arida (M.E. Jones) Romasch., also with sharp-pointed calluses, differs from our new species in having lemmatal awns 40-80 mm long that are obscurely 1-geniculate and scabrous throughout ( Barkworth 2007). Reports of E. arida from Hidalgo and Nuevo León, México ( Sánchez-Ken 2018) are perhaps in error since Dávila et al. (2018) did not record this species and Barkworth (2007) reported it as not found in México. Eriocoma perplexa (P.S. Hoge & Barkworth) Romasch. was reported in Dávila et al. (2018) and Sánchez-Ken (2018) as occurring in Coahuila but it was not included in Valdés Reyna's (2015), Gramíneas de Coahuila. It differs from E. valdesii in having shorter ligules 0.2-3.5 mm long [verses (2-) 4.5-8.5 mm long in E. valdesii ] and a blunt callus only 0.4-0.6 mm long (verses 1-1.4 mm) [ Barkworth 1993, 2007]. The new species can sometimes be confused with Eriocoma robusta (Vasey) Romasch., a much taller species up to 2.3 m tall with hairy collars, particularly on the flag leaves (glabrous or sparsely pubescent in E. valdesii ), florets with a blunt callus, and lemmatal awns that are 20-32 mm long with the lower two segments scabrous (lemmatal awns 12-24 mm long and lower two segments short hairy in E. valdesii ) [ Barkworth 2007; Valdés Reyna 2015]. The new species is most similar to Eriocoma alta (Swallen) Romasch. since both species share long ligules, long leaf blades up to 60 cm long, and florets with sharp-pointed calluses ( Swallen 1943). However, E. alta differs from the new species in having dark brown (verses straminious to light brownish in E. valdesii ) florets 4-5.5 mm long (verses 6-7.5 mm long) with awns 8-12 mm long (versus 12-24 mm long), the awns scaberulous below (verses short hairy below), and short upper glumes 7-8 mm long (verses 8-12 mm long). Peterson, Saarela & Romaschenko 23219 from Nuevo León differs from other collections of E. valdesii in having short, lacerate ligules about 2 mm long.

In our preliminary molecular DNA sequence analysis of most American species of Eriocoma there is a strongly-supported E. lobata I clade (including the type) found allied with E. coronata (Thurb.) Romasch., E. parishii (Vasey) Romasch., and E. perplexa ( Valdés Reyna et al. 2013). In another portion of our tree a strongly-supported clade of five accessions of E. valdesii (including Peterson, Romaschenko & Valdés Reyna 24469, the type collection) forms a trichotomy with two other strongly-supported clades containing three accessions of E. alta (including the type) and seven accessions of E. lobata II ( Valdés Reyna et al. 2013). All specimens examined below were sampled, except Hoge, Barkworth & Valdés Reyna 295, and formed a clade in our DNA analysis with the type.

Specimens examined.

México. Coahuila: Municipio de Saltillo, Highway 54 from Saltillo to Concepción del Oro, S to just past Estación Carneros, take road on right to tower, 2160 m, 18 Sep 1989, P.S. Hoge, M.E. Barkworth & J. Valdés Reyna 295 (ANSM, UTC); Sierra Madre Oriental, Estación Carneros, carretera 54, camino a la torre de microondas. 25°12'29"N, 101°24'01"W, 2258 m, 8 Sep 2008, Valdés Reyna & M.E. Barkworth 3085, 3087 (ANSM); 3 km above Estacion Carneros on road to radio tower, 25.12190N, 101.12006W, 2315-2400 m, 30 Oct 2019, P.M. Peterson, K. Romaschenko & J. Valdés Reyna 26818 (CIIDIR, US). Nuevo León: Municipio Galeana, 2.3 mi N of Hwy 31 on dirt road, 24.70478N, 100.16019W, 2222 m, 9 Sep 2010, P.M. Peterson, J.M. Saarela & K. Romaschenko 23219 (US, CIIDIR); 27 km SW of Galeana on Hwy 58 towards San Roberto, 24.68214N, 100.11637W, 2 Nov 2019, P.M. Peterson & K. Romaschenko 26884 (CIIDIR, US); Municipio Santa Catarina, edge of Parque Nacional Cumbres de Monterey, slopes above Puerto del Canejo, 25.49686N, 100.58644W, 2538-2721 m, 6 Sep 2010, P.M. Peterson, J.M. Saarela, K. Romaschenko & I. Cabral Cordero 23158 (US, CIIDIR). San Luis Potosí: Municipio Catorce, 3km E of San Jose de Coronados, 23.59105N, 100.89556W, 6 Nov 2019, P.M. Peterson & K. Romaschenko 26941 (CIIDIR, US). Tamaulipas: Municipio de Bustamante, 16 km al SE de Bustamante hacia La Presita y Tula. 23°21'N, 99°40'W, 1700 m, 26 May 1982, J. Valdés Reyna & M.A. Carranza 1474 (ANSM, US-3103546).

Figures

Figure 1. Eriocoma valdesii. A Habit B culm and panicle C panicle branch D sheath, ligule, and blade E lower glume F upper glume G floret H floret, enlarged I palea J palea, lodicules, ovary, and stamen K stamen L lodicules M ovary. Drawn from the holotype collection (Peterson, Romaschenko & Valdes Reyna 24469).