Agrostis subpatens Hitchc., in Britton, N. Amer. Fl. 17(7): 527. 1937.

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

16. Agrostis subpatens Hitchc., in Britton, N. Amer. Fl. 17(7): 527. 1937.

Figs 4O , 30C , 34

= Agrostis vinosa Swallen, Contr. U.S. Natl. Herb. 29(9): 402. 1950. Type. Guatemala. Huehuetenango: alpine meadow, vicinity of Chémal, summit of Sierra de los Cuchumatanes, 3700-3750 m alt., 8 Aug 1942, J. Steyermak 50290 (holotype: US (US00131130); isotypes: F (F0046567F [image!]), MO (MO-501391 [image!]), US (US00624107 [image!])).

Type.

Costa Rica. Cerro de la Muerte, 3100 m alt., Jan 1897, H. Pittier 10470 (holotype: US ( US 00131113); isotype: G (G00192032 [image!])) .

Description.

Plants perennial, caespitose. Tillers extravaginal, with cataphylls. Culms up to 30 cm long, erect, decumbent at the base, nodes 1-2, glabrous, internodes glabrous. Leaves mostly basal; sheaths 1-6 cm long, longer or shorter than the internodes, glabrous or scaberulous; ligules 2-3(5) mm long, longer than wide, dorsally scaberulous, apices acute, often lacerate; blades 2.2-10(15) cm long, 0.4-0.8 mm wide, filiform, conduplicate to convolute, sometimes flat at the base, scaberulous on both surfaces. Panicles 5-11.5 cm long, 0.5-4 cm wide, contracted to open, somewhat lax, linear to lanceolate, exserted from the upper sheaths; branches appressed to ascending, rebranching about mid-length or below, scaberulous, without spikelets near their base, inferior branches up to 2.8 cm long cm long; pedicels 2-7 mm long, usually longer than the spikelets, appressed to ascending, scaberulous. Spikelets 2.1-3 mm long, purplish; glumes subequal to unequal, lanceolate, apices acute to shortly acuminate, 1-veined, scaberulous on the keel, lower glume 2.1-3 mm long, upper glume 1.9-2.8 mm long; callus pubescent, with 2 bunches of trichomes; lemmas 1.3-2.2 mm long, elliptic, apices toothed, 5-veined, veins prominent distally, awned near the base, awn 3-3.5 mm long, weakly geniculate, reaching the lemma apices; paleas absent; anthers 3, 0.9-1.5 mm long. Caryopsis 0.8-1.5 mm long, elliptic; endosperm solid. 2n= 28 ( Pohl and Davidse 1971).

Anatomy and micromorphology.

Leaf blades convolute to v-shaped in transversal section; adaxial furrows deep, narrow; adaxial ribs rounded to triangular; keel absent; first order bundles circular in outline, sheath not interrupted, abaxial and adaxial sclerenchyma in strands; second order bundles circular in outline, sheath not interrupted, abaxial and adaxial sclerenchyma in strands; intercostal sclerenchyma present, abaxial; leaf margins with well-developed sclerenchyma caps, rounded; colorless cells absent (Fig. 31F, G ). Lemmas with transversal thickenings irregular to oblong, wider than the unthickened portion of the wall; prickle hairs abundant (Fig. 32C ).

Distribution and habitat.

Agrostis subpatens is distributed from Chiapas, Mexico to Costa Rica ( Pohl and Davidse 1994). It has also been reported from Venezuela ( Luteyn 1999). In the study zone, it has been collected in the Mexican state of Chiapas and in the Guatemalan departments of Chimaltenango and Huehuetenango (Fig. 26D ). This species has also been reported from Mexico City and the Mexican states of Hidalgo, Jalisco, México, Michoacán, Oaxaca, Puebla, Querétaro, Tlaxcala and Veracruz ( Villaseñor 2016; Dávila et al. 2018; Sánchez-Ken 2019; Vigosa-Mercado and Ruiz-Sánchez, 2020), but these records correspond to misidentified specimens of A. tolucensis and A. turrialbae . Agrostis subpatens grows in open areas of temperate forests with Pinus and Juniperus , and in alpine grasslands, between 2900-3790 m a.s.l. (Fig. 27D ).

Phenology.

Specimens with spikelets have been collected in January, August and September (Fig. 28D ).

Commentaries.

This species is similar to A. tolucensis and A. turrialbae , with which it shares the basal filiform leaves, as well as several leaf blade anatomy and lemma micromorphology characters. Agrostis subpatens differs from A. tolucensis in the less dense and often more open panicles, with pedicels usually longer than the spikelets (vs. usually dense and spiciform panicles, pedicels usually shorter than the spikelets in A. tolucensis ). It differs from A. turrialbae in the awned lemmas and absent palea (vs. unawned lemmas, palea up to 0.2 mm long in A. turrialbae ).

Conservation status.

Agrostis subpatens is known in the study zone from a few localities in southern Mexico and Guatemala. It is represented by seven collections, with several populations occurring in two protected areas. The EOO is 5,589 km2 and the AOO is 20 km2. Following the IUCN criteria, the preliminary assessment category is Endangered (EN).

Specimens examined.

Guatemala. Chimaltenango: Municipio Acatenango, slopes of Volcán de Acatenango, above Las Calderas , [14.52463248°N, 90.87729338°W], 2900 m alt., 3 Jun 1939, P.C. Standley 61878 (F) . Huehuetenango: Municipio Chiantla, Llano de Tsajualá, 3170 m alt., 26 Aug 1976, D.N. Smith 383 (F); cerca del cementerio, aldea San Nicolas , [15.43172006°N, 91.43878244°W], 3090 m alt., 3 Sep 1976, D.N. Smith 430 (F) . Municipio Todos Santos Cuchumatán, Cerro Alto entre Llano de San Miguel y Todos Santos Cuchumatán, [15.54382199°N, 91.57855143°W], 3790 m alt., 29 Aug 1976, D.N. Smith 411 (F); near Tojquiá, summit of Sierra de los Cuchumatanes , [15.54360741°N, 91.56627528°W], 3700 m alt., 7 Aug 1942, J.A. Steyermark 50230 (F, US) . Mexico. Chiapas: Municipio Siltepec, on the N and W slope of cerro Mozotal below the microwave tower along the road from Huixtla to El Porvenir and Siltepec , [15.4275°N, 92.341944°W], 3000 m alt., 19 Sep 1976, D.E. Breedlove 40355 (DS, MEXU [*, **]) .

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 26. Map of known geographic distribution of Agrostis species, based on herbarium specimen data A A. perennans B A. scabra C A. stolonifera D A. subpatens E A. subrepens F A. tolucensis.

Figure 27. Elevation histograms of Agrostis species A A. perennans B A. scabra C A. stolonifera D A. subpatens E A. subrepens F A. tolucensis G A. turrialbae H A. variabilis.

Figure 28. Phenology histograms of Agrostis species A A. perennans B A. scabra C A. stolonifera D A. subpatens E A. subrepens F A. tolucensis G A. turrialbae H A. variabilis.

Figure 30. Calluses of Agrostis species observed with SEM A A. scabra B A. stolonifera C A. subpatens D A. subrepens E A. tolucensis F A. turrialbae G A. variabilis. Scale bars: 50 μm.

Figure 31. Leaf blade anatomy in transversal section of Agrostis species, in general view, and details of lateral bundles. A - C A. scabra D - E A. stolonifera F - G A. subpatens H - I A. subrepens. Scale bars: 0.1 mm.

Figure 32. Lemma surface of Agrostis observed with SEM A A. scabra B A. stolonifera C A. subpatens D A. subrepens E A. tolucensis F A. turrialbae G A. variabilis. Scale bars: 15 μm.

Figure 34. Agrostis subpatens A whole plant B ligular area C spikelet D floret, lateral view, E floret, abaxial view. A based on Steyermark 50230 (US), B-E based on Breedlove 40355 (MEXU). Scale bars: 3 cm (A); 1 mm (B); 0.5 mm (C); 0.3 mm (D, E).