Poa pratensis pratensis

Soreng, Robert J. & Peterson, Paul M., 2012, Revision of Poa L. (Poaceae, Pooideae, Poeae, Poinae) in Mexico: new records, re-evaluation of P. ruprechtii, and two new species, P. palmeri and P. wendtii, PhytoKeys 15, pp. 1-104 : 49-51

16e. Poa pratensis pratensis Fig. 18 C-J

Description.

Tufts sparse, or dense to loose, shoots clustered, or some solitary; green, or bluish-gray-green; tillers intra- and extravaginal. Culms 8-100 cm tall. Ligules of lower culm and tiller leaves commonly glabrous abaxially; blades of cauline leaves flag leaf blades flat or folded, thin, soft; sterile shoot blades 10-45 cm long, 0.4-4 mm wide, some distinctly narrower than the cauline blades, all flat or some involute, usually glabrous adaxially. Panicles 5-18 cm long, loosely contracted or open and broadly pyramidal; rachis with 3-6(-9) branches per node; primary branches spreading to somewhat reflexed, smooth or sparsely to fairly densely scabrous; spikelets several to many per branch. Spikelets lanceolate to broadly lanceolate, not bulbiferous; glumes unequal to subequal, infrequently glaucous; lower glumes 1-3-veined; upper glumes shorter than or nearly subequaling the lowest lemma; lemmas 2.8-4.3 mm long, finely muriculate, intermediate veins glabrous; paleas scabrous, medially glabrous over the keels, intercostal region glabrous. Anthers sometimes sterile. 2 n = 41-44, 48-56, 58, 59, 60 ca, 62, 64-70,74, 86-91, 95, 98.

Distribution.

The subspecies occurs in Eurasia, North America (Canada, Greenland, USA), and Mexico (Baja California, Chihuahua, Coahuila, Distrito Federal, Hidalgo, Mexico, Nuevo León, Veracruz).

Ecology.

This introduced subspecies occurs mostly between 900-3500 m, in cool temperate habitats, probably in large part due to seeding for soil stabilization, pastures and lawns. Flowering May to July.

Specimens examined.

Mexico. Baja California: Municipio Ensenada, carretera a Tecate, coastal, 10 m, 23 Jun 1979, J. Sánchez 14 (MEXU). Rancho Don Faustina, 3 May 1981, R. Guzmán 1371 (MEXU). Sierra Juárez, Arroyo el Zauz, Laguna Hansen 32°00'N, 115°57'W, 1560 m, 13 May 1997, A.Miranda 574 (MEXU). Rancho Paraiso, km 153 carretera Ensenada-San Felipe, 31°21.305'N, 115°27.209'W, 900 m, 16 May 1997, M.A.Vergara-B. 100 (MEXU). Sierra San Pedro Mártir, Rancho Melling, 7 May 1981, C.Aguirre 258 & V.Morales (MEXU). Chihuahua: Mun icipio de Balleza, camino Balleza-Guachochic, km 45, 24 Sep 1981, I.Flavio-A. 1585, Rafael-F. and M.E.Siquerios (MEXU).Municipio de Madera, ejido El Largo, Rancho de la Ciénega, 2240 m, 24 Jul 1990, A. Benítez 1401 (MEXU). Coahuila: Municipio Arteaga, Cañon Jamé, ca. 20 km al del poblado de Jamé; 25°22'N, 100°35'W, 2200 m, J.A.Villarreal 5885 & M.A.Carranza (TEX); ditto, Sierra de la Marta, La Siberia, ca del Ejido Santa Rita, ca. 6 km al southeast de San Antonio de las Alanzanas, 25.2203°12'N, 100°30'W, 2300 m, 27 May 1982, J.A.Villarreal 1687 (TEX). Sierra de Arteaga, de San Antonio de las Alanzanas a Sierra la Marta y porrero de Abrego, 25°25'N, 100°40'W, 2300 m, 20 Jun 1984, J.Valdes-R. 1664 & M.E.Demesa (TEX). Distrito Federal: Region Contreras, volcani, 2700 m, 5 May 1926, M.St.Pierre s.n. (US). Canada de Contreras, ca. de Primer Dinamo, 2550 m, 16 Jun 1970, J.Rzedowski 27216 (MEXU, US). Pedregal de San Angel, SE del Pedregal, 16 May 1952, J.Rzedowski 1002 (US). Municipio De Chalco, faldas del Cerro Telapón, 3200 m, 16 Jul 1964, J.Rzedowski 18460 (MEXU). alrededores de la estacion La Cima, delegacion de Tlalpan, 3000 m, 8 Jul 1979, J.Rzedowski 36171(MEXU, TAES). 5 km al W del Desierto de los Leónes sobre el camino a La Cieneguilla, 3250 m, 5 Jun 1983, J.Rzedowski 38086 (MEXU). Hidalgo: Municipio de Epazoyucan, ca. de Peñas Largas, 2900 m, 3 Aug 1975, J.Rzedowski 33439 (TAES, toward alpigena). Municipio Mineral del Chico, 2 km de Llanos Grandes por camino a Peña del Cuervo, 2900 m, 13 Jun 1992, M. González-Ledesma 502 & J.A. Pérez-de-la-Rosa (MEXU). Mexico: Municipio Ixtapaluca, Estacion Exper. Forestal de Zoquiapan, 3300 m, Jul 1976, C.Obieta-O. 91 (MEXU).Sierra del Ajusco, Rancho Alegre, delegacin Tlalpan, 3400 m, 29 Nov 1981, R.C.Moreno-C. 83 (TAES, hybrid?). Mexico: A 7 km de Buenavista, a Temascaltepec, 3250 m, 29 Aug 1983, Manrique 282, Jarmillo & Guerrero (MEXU). EEFZ, Cercanias as Cerro El Papayo, 3250 m, 16 May 1997, E. Guízar s.n. et al. (MEXU). 4 km del camino de terraceria hacia el campo EEFZ, 3330 m, 29 Jul 1998, B.Nava-Roberto-C. s.n. (MEXU). Río Frío, 3000 m, 19 Apr 1997, O.Ruiz-N. (MEXU). ca. Paso de Cortés, entre Popocatépetl e Ixtaccíhuatl, 3650 m, 31 Jul 1966, J.Rzedowski 22841 (TAES, appear to be intermediate to Poa orizabensis ). Municipio Tlalmanalco, Vertiente occidental del Volcán Ixtaccihuatl, 8 km al se de San Rafael, 3125 m, 6 Apr 1997, S.D.Koch 7917 & I.Sanchez-V. (MEXU, MO); ditto, C.Azudia 44 (MO, MEXU). Bosque de San Rafael, 10 May 1971, E.Matuda 38360 (MEXU). Municipio Ixtapaluca, Llano Pinahua, 8 km al southwest de Río Frío, 3200 m, 24 May 1981, J.Rzedowski 37286 (TAES).Municipio Mineral del Chico, Las Ventanas, 2960 m, 19 May 1993, J.Praxedes 49, Pérez,Jiménez (MEXU). Nuevo León: Areas cercanas a Cola de Caballo, 25°23'N, 100°10'W, 800 m, 30 May 1987, J.A.Villarreal 3691 & M.A.Carranza (TAES). Veracruz: Municipio Chiconquiaco, La Guacamaya, 1900 m, 26 Mar 1975, F.Ventura-A. 11133 (MEXU, TAES). Municipio Perote-Perote, Jun 1893, E.W.Nelson 19 (US). camino entre Perote y Cofre el Perote, 2950 m, 24 Apr 1982, R. Guzmán 4980 (MEXU). camino a El Conejo, 19°31'42"N, 97°09'21"W, 3500 m, 3 Jun 1994, C.R.Galindo 63 (MEXU). mountains near Jalapa, 5000-7000 ft [1525-2135 m], 20 Apr-20 May 1899, C.G.Pringle 7880 (US). Lomogrande, Mt. Orizaba, 8900 ft [2715 m] 28 Apr 1938, E.K.Balls 4382 (US). Muni cipio Rafael Ramírez, comunidad Los Paisanos, 19°34' 12"N, 97°05' 25"W, 28 Mar 1995, P.J. Parroquín 79 (MEXU). Barranca Seca, ca. de La Desviacíon a Villa Aldama, 2350 m, 8 Aug 1970, F.Ventura-A. 1993 (MO, toward alpigena or irrigata). Cofre de Perote, 3300 m, Apr 1987, B.Veracruz 251 (MEXU, toward alpigena). Cofre de Perote, east side, 3930 m, 6 Aug 1958,J.H.Beaman 2179 (MEXU, TEX, US, toward alpigena). Cruz Blanca, 8000-10000 ft [2440-3050 m], 21 May 1950, J.T.Baldwin Jr.14281(US, toward alpigena).

Discussion.

This subspecies is commonly included in cool temperate pasture and lawn grass seed mixes. More than 140 of the 162 chromosome counts RJS has compiled from the literature for this taxon are between 2 n = 50 and 78. The collection of J.Rzedowski 22841 seems a bit intermediate between this subspecies and Poa orizabensis , since it has dense, scabrous branches, lightly pubescent lemma keels and marginal veins, and slightly pointed ligules. The collection of R.C.Moreno-C. 83 is odd for its dense low tuft, with short, flat blades, lack of rhizomes, and smooth branches, combined with large spikelets, and may represent another inter-species hybrid.

Figures

Figure 18. Poa pratensis L. A, B Poa pratensis subsp. irrigata (Lindm.) H. Lindb. A habit B spikelet C-J subsp. pratensis C habit D sheath, ligule blade lateral view E blade apex lateral view F blade apex adaxial view G inflorescence H branch segment with spikelets I spikelet J floret. Drawings from Soreng (2007).