Agrostis boyacensis Swallen & Garcia-Barr ., Caldasia 2 (8): 303, fig. A. 1943

Sylvester, Steven P., Cuta-Alarcon, Lia E., Bravo-Pedraza, William J. & Soreng, Robert J., 2020, Agrostis and Podagrostis (Agrostidinae, Poaceae) from paramos of Boyaca, Colombia: synoptic taxonomy including a key to Colombian species, PhytoKeys 151, pp. 107-160 : 107

Agrostis boyacensis Swallen & Garcia-Barr., Caldasia 2 (8): 303, fig. A. 1943 Figs 1 , 2

Type.

Colombia. Boyacá: Nevado del Cocuy, alto valle de Las Lagunillas, [6.3906N, 72.3542W], 4000-4300 m alt., 12 Sep. 1938, J. Cuatrecasas & H. García-Barriga 1459 (holotype: US (US00131729 [image!]); isotype: COL (COL000006092!), SI (SI000494 [image!] fragm. ex US)).

Description.

Perennial herbs, densely tufted, often stooling with perenniating many-branched culms, often with short lateral tending to ascending rhizomes. Tillers extravaginal, with cataphyllous shoots present. Culms 3-24 cm tall (to 37 cm tall in specimens from Boyacán páramos outside the Sierra Nevada del Cocuy), erect to arched, firm, with 0(-2) nodes exerted at flowering, densely scabrous throughout or scabrous just below the nodes, or rarely smooth (specimens from Boyacán páramos outside the Sierra Nevada del Cocuy). Leaves basal and cauline, often mainly basal, glabrous, usually densely scabrous throughout, less often smooth or scaberulous (specimens from Boyacán páramos outside the Sierra Nevada del Cocuy); ligules 0.9-2 mm long, membranous or slightly scarious, truncate to triangular and obtuse, moderately to strongly decurrent with the sheath, abaxial surface smooth or scaberulous; blades (2-)3-6(-12) cm long, 0.5-1.2(-1.5) mm in diameter as folded or rolled, convolute, involute, or strongly conduplicate, usually recurved or sometimes straight, firm to rigid, those of upper culm sometimes flat, firm, 2-3 mm wide, abaxial surface usually densely scabrous throughout, less often smooth to scaberulous (specimens from Boyacán páramos outside the Sierra Nevada del Cocuy), adaxial surface and margins moderately to densely scabrous, apices blunt or slightly naviculate-acute. Panicles (2-)3-6(-8) cm long, c. 0.3-0.7(-0.9) cm wide, moderately to densely congested, sub-spikelike to spikelike, generally not interrupted, subincluded in the basal foliage to greatly exerted, lateral branches with spikelets usually present almost to the base, upper lateral branches short and held close to the central inflorescence axis, central axis and panicle branches moderately to densely scabrous, rarely smooth or scaberulous (specimens from Boyacán páramos outside the Sierra Nevada del Cocuy); pedicels 0.8-2.5 mm long, usually shorter than their spikelets, not obviously dilated at their apex, moderately to densely scabrous, sometimes smooth or scaberulous (specimens from Boyacán páramos outside the Sierra Nevada del Cocuy). Spikelets 1.8-2.4(-2.5) mm long; glumes usually unequal, sometimes subequal, the lower longer than the upper by up to 0.3 mm and usually wider than the upper, 1-veined, lower glume keel scabrous throughout to only in distal 1/3, upper glume scabrous only in the distal 1/3 or sometimes smooth throughout, apices acute; floret 3/5-2/3(-3/4) the length of the glumes; calluses glabrous or with 2 sparse tufts of very short hairs on the lateral sides; lemmas 1-1.5 mm long, glabrous, smooth, 5-veined, apex obtuse to slightly truncate, erose, muticous or exceptionally with a short straight awn inserted in the upper ½ of the lemma, to 0.5 mm long, not surpassing the glume apex, weak and falling easily (i.e. Sylvester 3071); paleas absent or to 0.3 mm long, < ¼ the length of the lemma; rachilla absent; anthers 0.5-0.8(-1) mm long.

Distribution and ecology.

Colombia, Ecuador?. Páramos and superpáramos, found in both zonal grass páramo and azonal high elevation moraine, 2850-4500 m alt. Within Colombia, the species seems to be found only in the Cordillera Oriental, with specimens only seen from Departamento Boyacá. Luteyn (1999) mentions the species to be found in Ecuador and the species is also mentioned in the key to some Ecuadorian taxa ( Palacio et al. in press), but no specimens have been verified at US.

Other specimens examined.

Colombia. Boyacá: Munic. Chiscas, Páramo de Chacaritas, found on a rock escarpment 4 m tall, 6.62227N, 72.39040W, 4192 m alt., 4 Mar. 2018, S.P. Sylvester 3117 (K, UPTC, US); Munic. Chiscas, Páramo de Chacaritas, close to the foot of the talus scree slope, 6.61779N, 72.38899W, 4354 m alt., 4 Mar. 2018, S.P. Sylvester 3129 (COL, FMB, K, US); Sierra Nevada del Cocuy, Laguna Grande, in open gravelly slopes, morranes and similar places at high altitude, [6.5556N, 72.3253W], 4300-4500 m alt., 28 Dec. 1985, J.R.I. Wood 5247 (US3481052); Munic. Duitama, Páramo de la Rusia, Sector del Páramo de Agueros, en la vía que conduce a la vereda Avendaños, páramo dominado por Chusquea , evidencia de pastoreo intenso, en alguna perturbación humano / animal, 5.94611N, 73.08481W, 3768 m alt., 3 Oct. 2017, S.P. Sylvester 3017a (COL, K, SI, US); Munic. Arcabuco, Vereda el Carmen, Páramo del Valle, páramo muy húmedo dominado por el grupo Chusquea , pastoreo natural, 5.75425N, 73.38303W, 3430 m alt., 15 Nov. 2017, S.P. Sylvester 3071 (K, US, SI). Munic. Chiscas, Páramo de Chacaritas, rocas expuestas en vegetación de páramo, 6.61931N, 72.38898W, 4287 m alt., 4 Mar. 2018, S.P. Sylvester 3124 (K, US, SI). Munic. Mongua, Páramo de Ocetá, valle de Laguna Negra, vegetación de frailejonal pajonal, con presencia de arbustos pequeños, Se observan rastros de pastoreo, 5.69525N, 72.79133W, 3694 m alt., 29 Nov. 2017, L.E. Cuta-Alarcón 353c (US); Planos del Toldadero, [6.3669N, 72.3342W], 3950 m alt., 13 Sep. 1938, J. Cuatrecasas 1554 (US17730370); Sierra Nevada del Cocuy, alrededores de Salto de Correlitos, [6.4444N, 72.3175W], 4400 m alt., 14 Apr. 1959, H.G. Barclay 7394 (US2434358); Sierra Nevada del Cocuy, Alto Ritacuva, [6.5139N, 72.3531W], 4450 m alt., between wet slopes which have dense Espeletia , 24 Apr. 1959, H.G. Barclay 7453 (US2434361); Sierra Nevada del Cocuy, alrededores de Salto de Correlitos, rocky, southwest-facing slope, better vegetated between rocky ridges, east of Laguna San Paulino, [6.4444N, 72.3175W], 4300 m alt., 14 Apr. 1959, H.G. Barclay 7381 (US2434355); Sierra Nevada del Cocuy, alto valle de Las Lagunillas, [6.3469N, 72.3261W], 4000-4300 m alt., 12 Sep. 1938, J. Cuatrecasas 1465 (US1772998); Sierra Nevada del Cocuy, Alto Valle Lagunillas, morrena seca pedregosa 100 m al SE de la Laguna Cuadrada, [6.3619N, 72.3344W], 4080 m alt., con Calamagrostis effusa [(Kunth) Steud. = Paramochloa effusa (Kunth) P.M. Peterson, Soreng, Romasch. & Barberá] y Gymnomitriaceae predominantes, asociadas con Luzula , Espeletia colombiana [Cuatrec.] y musgos, 26 Nov. 1972, A.M. Cleef 5535 (US2785729); Sierra Nevada del Cocuy, Alto Valle Lagunillas, [6.3906N, 72.3542W], 3995 m alt., con Espeletia colombiana predominante, asociada con Aciachne pulvinata [Benth.], Agrostis breviculmis , Agrostis trichodes [ Podagrostis trichodes ] y Acaena cylindristachya [Ruiz & Pav.], gramínea común, 25 Sep. 1972, A.M. Cleef 5504 (US2785744); Sierra Nevada del Cocuy, Boqueron de Cusiri, límite superpáramo y páramo propiamente dicho, vertiente seco muy pedregoso, [6.3431N, 72.3128W], 4320 m alt., con Calamagrostis effusa [= Paramochloa effusa ] y Espeletia cleefii [Cuatrec.], gramínea común, 5 Mar. 1973, A.M. Cleef 8796 (US2785680); Sierra Nevada del Cocuy, Laguna Grande de la Sierra, [6.5556N, 72.3253W], 4300-4500 m alt., 28 Dec. 1985, J.R.I. Wood 5247 (US3481052); Sierra Nevada del Cocuy, Páramo Cóncavo, Cuchilla Puentepiedra casi 2km al NE de la Laguna Pintada, vertiente pedregoso seco, [6.3723N, 72.3175W], 4510 m alt., con Calamagrostis effusa [= Paramochloa effusa ], Poa sp., asociadas con Espeletia lopezii fma. [Cuatrec.], y musgos, 30 Sep. 1972, A.M. Cleef 5665 (US2785695); Sierra Nevada del Cocuy, Páramo Cóncavo, morrena seca en el límite páramo propiamente dicho y superpáramo, 3.5 km al NNW del Morro Pulpito del Diablo, [6.3995N, 72.3123W], 4325m alt., matorral de Senecio vaccinioides [Cuatrec.] con Alchemilla sp., 1 Mar. 1973, A.M. Cleef 8680 (US2785780); Sierra Nevada del Cocuy, Páramo Cóncavo, superpáramo, morrena seca 3 km aprox. al Norte del morro Pulpito del Diablo. [6.3995N, 72.3123W], 4375m alt., rastrojo de Senecio guicanensis [Cuatrec.], gramínea común, 28 Feb. 1973, A.M. Cleef 8627 (US2785676); Sierra Nevada del Cocuy, Páramo Cóncavo, superpáramo 3.5 km aprox. al NNW del morro Pulpito del Diablo, morrena seca muy pedegrosa, [6.3995N, 72.3122W], 4315 m alt., con Luzula y Pernettya prostrata var. prostrata [(Cav.) DC.], gramínea común, 26 Feb. 1973, A.M. Cleef 8504 (US01247250); Sierra Nevada del Cocuy, Páramo Cóncavo, superpáramo abrigo rocoso denominado Cueva de los Hombres, 3 km aprox. al N del morro Pulpito del Diablo, [6.3995N, 72.3122W], 4350 m alt., 28 Feb. 1973, A.M. Cleef 8608 (US2785679); Sierra Nevada del Cocuy, Quebrada Bocatoma, vertiente N del valle, 800 m al ENE [East North-East] de la Laguna Pintada, [6.4795N, 72.3167W], 4060 m alt., Stephaniella sp. predominante asociada con Calamagrostis effusa [= Paramochloa effusa ], Alchemilla polylepis [Wedd.], Achyrocline lehmanii [Hieron.] y Polytrichum sp., 29 Sep. 1972, A.M. Cleef 5648 (US2785702).

Notes.

Specimens encountered from páramos not belonging to the Sierra Nevada del Cocuy, but within Departamento Boyacá, bear notable differences from those from the type locality and further study is needed to elucidate whether these are a distinct species or subspecies of A. boyacensis . These differences include leaf sheaths and blades, panicle branches, and pedicels being usually smooth or very lightly scaberulous, and plants being larger, usually> 20 cm tall and up to 37 cm tall, and with the panicles largely exerted from the basal foliage (Fig. 2 ). These characteristics place it close to A. meyenii , which is not known from Colombia ( Giraldo-Cañas et al. 2016) or páramos in general ( Luteyn 1999), although it is mentioned in the recently-published abbreviated key to some Ecuadorian species ( Palacio et al. in press) (see below for how to differentiate these species).

The habit of type specimens and some of the other specimens examined (e.g. Sylvester 3117 and 3129), with perenniating, many-branched culms, appears to be related to the habitat, with the Sylvester 3117 and 3129 specimens being found growing amongst moss. The leaf blades of these were also slightly laxer, albeit still involute or strongly conduplicate. In harsher conditions, such as open gravelly slopes, the tufts are more compact and leaf blades are rigid and strongly rolled and resemble a very large, densely-tufted A. breviculmis with slightly laxer panicles.

Similar species.

Agrostis breviculmis and A. meyenii both have congested spikelike panicles and florets that lack prominent awns and well-developed paleas. Agrostis breviculmis bears close similarity in its convolute, often recurved, rigid to firm leaf blades that usually measure <1 mm wide in diameter, and small spikelets with fairly well developed coarse scabers on the glume keels. Agrostis boyacensis can be distinguished from A. breviculmis principally by the habit, with many extravaginally branched culms that form large dense tufts to 37 cm tall (vs. intravaginal innovations forming short tufts to 12(-15) cm tall in A. breviculmis ), laxer panicles, 3-9 mm wide (vs. c. 0.5-2 mm wide in A. breviculmis ), and slightly larger spikelets, 1.8-2.4(-2.5) mm long (vs. usually 1.5-2.1 mm long in A. breviculmis , noted to reach 2.5 mm long in Bolivia [ Renvoize 1998]).

Agrostis boyacensis can be distinguished from A. meyenii principally by its robust convolute, involute or strongly conduplicate, usually recurved and rigid leaf blades (vs. laxer, weaker, flat or folded, usually filiform leaf blades in A. meyenii ). All specimens encountered from the Sierra Nevada del Cocuy can be easily differentiated by their panicle branches, pedicels, and leaf sheaths and blades that are moderately to densely scabrous (vs. panicle branches and pedicels smooth to lightly scaberulous, leaf sheaths smooth, blades smooth or scabrous in A. meyenii ). Specimens collected in other páramos from Departamento Boyacá, outside of the Sierra Nevada del Cocuy, bear further similarities with A. meyenii , such as their culms and inflorescences being longer and greatly exerted from the basal foliage, and panicle branches, pedicels, and leaf blades that are usually smooth to lightly scaberulous (Fig. 2 ). Nevertheless, these can be differentiated from A. meyenii by a) their robust convolute, involute or strongly conduplicate, rigid and usually recurved leaf blades; b) the glumes usually being unequal, with the lower glume longer and usually wider than the upper; and c) the lower glume keel scabrous throughout to only in distal 1/3, the upper glume keel scabrous only in the distal 1/3 or sometimes smooth throughout.

Agrostis tolucensis has a congested spikelike panicle and florets with a minute palea and a lemma that can sometimes lack awns (see notes under A. tolucensis ). This species usually has leaf blades filiform, flat, or folded, lax to firm, but can sometimes have basal leaf blades involute or convolute and firm to rigid. All specimens examined at US with involute or convolute and rigid leaf blades had lemmas with a well-developed dorsally inserted awn. Further distinction from A. boyacensis can be found in how the leaf blades are smooth or scabrous only on the margin and sometimes veins in A. tolucensis , while scabrous throughout (margin, veins, and in-between veins) in A. boyacensis from the Sierra Nevada del Cocuy, although A. boyacensis specimens from other Boyacan páramos have blades smooth to scaberulous.

The sometimes strongly conduplicate leaf blades of this species can also give it a resemblance to A. foliata , which has subcoriaceous to coriaceous leaf blades that can sometimes be folded, although these are usually> 1.5 mm wide when opened out, and lemmas with well-developed awns inserted in the lower 1/2 of the lemma.

Figures

Figure 1. Agrostis boyacensis, examples of specimens from paramo or superparamo of the Sierra Nevada del Cocuy A whole plant B close-up of inflorescence C spikelet at anthesis, lateral view D upper culm blades and ligular area E floret, ventral view F floret, dorsal view. Images A, C, D, F: Cleef 8504 (US 01247250) courtesy of United States National Herbarium (US); B, E: Cleef 5665 (US 2785695). Scale bar of E also for F.

Figure 2. Agrostis boyacensis, example of a specimen encountered in paramos of Boyaca outside of the Sierra Nevada del Cocuy A whole plant B spikelet, glumes lateral view and floret ventral view showing anthers C spikelet, glumes lateral view with floret detached and raised above the glumes showing ventral surface. Images of Sylvester 3017 a (FMB).