Agrostis ghiesbreghtii E. Fourn., Mexic. Pl. 2: 97. 1886.

Vigosa-Mercado, J. Luis, Delgado-Salinas, Alfonso, Alvarado Cardenas, Leonardo O. & Eguiarte, Luis E., 2023, Revision of the genus Agrostis (Poaceae, Pooideae, Poeae) in Megamexico, PhytoKeys 230, pp. 157-256 : 157

6. Agrostis ghiesbreghtii E. Fourn., Mexic. Pl. 2: 97. 1886.

Figs 4F , 5F , 16

Agrostis ghiesbreghtii E. Fourn. ex Hemsl., Biol. Cent.-Amer., Bot. 3: 551. 1885, nom. nud.

= Agrostis setifolia E. Fourn., Mexic. Pl. 2: 97. 1886, nom. illeg. hom., non Brot., 1804. Agrostis setifolia E. Fourn. ex Hemsl., Biol. Cent.-Amer., Bot. 3: 551. 1885, nom. nud. Type. México. Veracruz: pic d’Orizaba, F.M. Liebmann 712 (holotype: C (C10016729 [image!])).

Type.

Mexico. Oaxaca: Province d’Oaxaca, 1842, A. Ghiesbreght s.n. (holotype: P (P00740574 [image!]); isotype: US [fragm. ex P] ( US 00156357 [image!])) .

Description.

Plants perennial, caespitose. Tillers extravaginal, with cataphylls. Culms 30-90 cm long, erect, rarely shortly decumbent at the base, nodes 2-5, glabrous, internodes glabrous. Leaves basal and cauline; sheaths 4-10 cm long, the lower ones shorter than the internodes, the upper ones longer, glabrous; ligules 1.5-6(-12) mm long, longer than wide, dorsally scaberulous, apices acute, often lacerate; blades 3.5-27 cm long, 1-3.5(-5) mm wide, stiff, linear, convolute or involute, the upper ones sometimes flat, scaberulous on both surfaces. Panicles 8-30 cm long, 5-19 cm wide, open, lax, ovate, usually long-exserted from the upper sheaths; branches spreading, rebranching about or above mid-length, scaberulous, without spikelets near their base, inferior branches 1.5-10 cm long; pedicels 2.5-5(-10) mm long, ascending to spreading, scaberulous. Spikelets (2.5-)3-4 mm long, usually purplish; glumes subequal to unequal, lanceolate, apices acute to shortly acuminate, 1-veined, scaberulous on the keel, lower glume (2.5-)3-4 mm long, upper glume (2.2-)2.7-3.9 mm long; callus pubescent, with 2 bunches of trichomes; lemmas (1.5-)1.8-2.5 mm long, elliptic, apices irregularly toothed, 5-nerved, veins prominent, awned from near the base, awn 2.3-5 mm long, geniculate; paleas absent, or up to 0.2 mm long, veinless, glabrous; anthers 3, 1-1.5 mm long. Caryopsis 1.2-1.5 mm long, elliptic; endosperm soft. 2n= unknown.

Leaf anatomy. Leaf blades convolute, rarely flat in transversal section; adaxial furrows deep, narrow; adaxial ribs rounded; keel absent; first order bundles circular in outline, sheath interrupted adaxially and abaxially, abaxial and adaxial sclerenchyma in girders; second order bundles circular in outline, sheath interrupted abaxially, abaxial sclerenchyma in girders, narrowing towards the bundle, adaxial sclerenchyma in strands; intercostal sclerenchyma usually present, a hypodermal band, sometimes absent; leaf margins with sclerenchyma continuous with the hypodermal band; colorless cells absent (Fig. 15D, E ). Lemmas with transversal thickenings oblong, wider than the unthickened portions of the wall; prickle hairs abundant (Fig. 7F ).

Distribution and habitat.

Endemic. Agrostis ghiesbreghtii is distributed from central Mexico to Guatemala. In Mexico, it has been collected in Mexico City and the states of Chiapas, Guanajuato, Guerrero, Hidalgo, México, Michoacán, Morelos, Oaxaca, Puebla and Veracruz (Fig. 8F ). It is also reported from Chihuahua and Durango ( Sánchez-Ken 2019), but no specimens from these states were seen. In Guatemala, it has been collected in the departments of Quetzaltenango and Sacatepéquez. This species grows in open areas of temperate forests, with Abies , Pinus , Quercus , and alpine grasslands, between 1110-3700 m a.s.l. (Fig. 9I ).

Phenology.

Flowering and fruiting specimens have been collected year round, but most of them between the months of August and February (Fig. 10I ).

Commentaries.

This species is similar to A. laxissima in the open panicles, awned lemmas and lemma micromorphological features, but it is distinguished in the leaf blades stiffer, usually convolute or involute, with deep adaxial furrows and usually with a hypodermal bland of abaxial sclerenchyma, and usually larger spikelets of (2.5-)3-4 mm long (vs. leaf blades lax, flat, with medium-sized adaxial furrows, without intercostal sclerenchyma, spikelets of 1.7-3 mm long in A. laxissima ). Some specimens with unusually wide and flat upper leaf blades have been collected in Guerrero and Chiapas, but the other characters are congruent with A. ghiesbreghtii . This species is also very similar to A. mertensii , and more studies are needed to define its taxonomic boundaries (see the notes in excluded species).

Conservation status.

Agrostis ghiesbreghtii is a widespread species in the study zone. It is represented by 80 collections, with several populations occurring in 12 protected areas. The EOO is 240,863 km2 and the AOO is 176 km2. Following the IUCN criteria, the preliminary assessment category is Least Concern (LC).

Representative specimens examined.

Guatemala. Sacatepéquez: Distrito Alotenango, Volcan de Acatenango , [14.499453°N, 90.87175°W], 3700 m alt., 10 Apr 2000, M. Véliz et al. 8303 (MEXU), 8371 (MEXU). Quetzaltenango: Distrito Quetzaltenango, Volcán Santa María, upper NE facing slopes to summit of volcano, [14.7583°N, 91.5492°W], 3600 m alt., 13 Jan 1940, J.A. Steyermark 34160 (F) . Mexico. Chiapas: Municipio Motozintla, near summit of cerro Mozotal, [15.42605394°N, 92.34362676°W], 2750 m alt., 24 Nov 1981, D.E. Breedlove 55885 (MICH, MEXU [*], TEX), 55893 (MEXU, MO). Guanajuato: Municipio Xichú, Sierra de Xichu , [21.28736944°N, 100.0888472°W], 1900 m alt., 19 Sep 1981, A. Mora 281-AMB (MEXU). Guerrero: Municipio General Heliodoro Castillo, Escalerilla, [17.47217778°N, 100.0386778°W], 2550 m alt., 1 Nov 1998, N. Diego 8296 (FCME [*], MEXU); cerro Teotepec, [17.46666667°N, 100.2166667°W], 3350 m alt., 11 Apr 1963, J. Rzedowski 18137 (ENCB, F, IEB, MICH). Hidalgo: Municipio Mineral del Chico , alrededores de Las Ventanas, 5 km al N de Pachuca, [20.19252776°N, 98.73954093°W], 2900 m alt., 2 Nov 1983, S Acosta et al. 416 (FCME, MEXU [*,**], UAMIZ, XAL). Municipio Zimapán, 11 km al S de La Luz, [20.733333°N, 99.366667°W], 1100 m alt., 10 Jan 1991, V.M. Huerta 1165 (CIB, IEB, XAL) . México: Municipio San Simón de Guerrero, 3 km sobre la desviación de Simón de Guerrero, carretera hacia Sultepec, [19.01857206°N, 100.0280164°W], 2870 m alt., 7 Feb 1984, E. Manrique et al. 673 (MEXU). Mexico City: Alcaldía Cuajimalpa, loma La Vaquera (arroyo Agua de Leones ), 3220 m alt., 16 Oct 1985, A. Miranda and P. Guerrero 136a (MEXU). Michoacán: Municipio Contepec, cerro Altamirano, Reserva de la Biósfera Mariposa Monarca, 19.96667°N, 100.13333°W, 3027 m alt., 6 Mar 2005, J. Martínez 1453 (IEB, MEXU [**]). Morelos: Municipio Huitzilac, Zempoala, [19.03333333°N, 99.3°W], 3000 m alt., 3 Nov 1951, E. Matuda 26005 (MEXU, US). Oaxaca: Municipio Santa María Tlahuitoltepec, SE slopes of Sierra Zempoaltepetl, [17.129956°N, 96.01353°W], 3300 m alt., 7 Aug 1950, H.S. Gentry 9231 (MEXU [*]). Municipio San Martín Peras: Santiago Juxtlahuaca, San Martín Peras, carretera Tecomaxtlahuaca-San Martín Peras, 2 km de la intersección a Coicoyán de las Flores, 17.2963333°N, 98.195528°W, 2570 m alt., 17 Oct 1994, J.L. Panero et al. 5117 (MEXU [*], TEX). Puebla: Municipio Atzitzintla, Teamalaquilla [Texmalaquilla], [18.943056°N, 97.2875°W], 3100 m alt., 29 Aug 1938, E.K. Balls 5393 (MICH, MSC, US). Veracruz: Municipio Calcahualco, barranca de San Miguel Tlacotiopa, [19.11192082°N, 97.20509861°W], 2700 m alt., 19 Jan 1989, P. Tenorio 15470 (CIIDIR, MEXU [*,**]). See the Suppl. material 2 for additional examined specimens .

Figures

Figure 4. Florets of Agrostis species observed with SEM A A. bourgaei B A. calderoniae C A. capillaris D A. elliottiana E A. exarata F A. ghiesbreghtii G A. gigantea H A. hyemalis I A. laxissima J A. microphylla K A. pallens L A. perennans M A. scabra N A. stolonifera O A. subpatens P A. subrepens Q A. tolucensis R A. turrialbae S A. variabilis. Scale bars: 0.3 mm.

Figure 5. Calluses of Agrostis species observed with SEM A A. bourgaei B A. calderoniae C A. capillaris D A. elliottiana E A. exarata F A. ghiesbreghtii G A. gigantea H A. hyemalis I A. laxissima J A. microphylla K A. pallens L A. perennans. Scale bars: 50 μm.

Figure 7. Lemma surface of Agrostis observed with SEM A A. bourgaei B A. calderoniae C A. capillaris D A. elliottiana E A. exarata F A. ghiesbreghtii G A. gigantea H A. hyemalis I A. laxissima J A. microphylla K A. pallens L A. perennans. Scale bars: 15 μm.

Figure 8. Map of known geographic distribution of Agrostis species, based on herbarium specimen data A A. bourgaei B A. calderoniae C A. capillaris D A. elliottiana E A. exarata F A. ghiesbreghtii.

Figure 9. Elevation histograms of Agrostis species A all records B native species C introduced species D A. bourgaei E A. calderoniae F A. capillaris G A. elliottiana H A. exarata I A. ghiesbreghtii J A. gigantea K A. hyemalis L A. idahoensis M A. laxissima N A. microphylla O A. pallens.

Figure 10. Phenology histograms of Agrostis species A all records B native species C introduced species D A. bourgaei E A. calderoniae F A. capillaris G A. elliottiana H A. exarata I A. ghiesbreghtii J A. gigantea K A. hyemalis L A. idahoensis M A. laxissima N A. microphylla O A. pallens.

Figure 15. Leaf blade anatomy in transversal section of Agrostis species, in general view, and details of lateral bundles A - C A. exarata D - E A. ghiesbreghtii F - H A. gigantea I - K A. hyemalis. Scale bars: 0.1 mm.

Figure 16. Agrostis ghiesbreghtii A whole plant B ligular area C spikelet D floret, lateral view, E floret, abaxial view. Based on Gentry 9231 (MEXU). Scale bars: 3 cm (A); 1 mm (B); 1 mm (C); 0.5 mm (D, E).