Poa ruprechtii Peyr., Linnaea 30(1): 6-8. 1859.

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 : 51-54

17. Poa ruprechtii Peyr., Linnaea 30(1): 6-8. 1859. Figs 13 P-R 16

Type:

Mexico, Toluca, Cocustepec, Volcán Toluca, 8800 ft [2440 m], Carl Heller 312. (holotype: W-0002241!). Poa sharpii Swallen, Contr. U.S. Natl. Herb. 29(9): 400. 1950. Type: Mexico, Veracruz, moist shaded soil near El Puerto, 7700 ft [2350 m], 6 Sep 1944, A.J.Sharp 44688 (holotype: US-1939432!; isotype MO-1410403!). Poa venosa Swallen Contr. U.S. Natl. Herb. 29(9): 399. 1950. Type: Guatemala, Huehuetenango, in alpine meadow, vicinity of Chémal, summit of Sierra de los Cuchumatanes, 3700-3750 m, 8 Aug 1942, J.A.Steyermark 50310 (holotype: US-1935067!; isotypes: F-1201922, ISC-v-0000603 (image and fragment ex US)!, MO!).

Description.

Hermaphroditic or simple gynomonoecious. Perennials; tufted, sometimes sub-rhizomatous, tufts loose, narrow to medium girth, medium height, green; tillers extravaginal (basally cataphyllous), with lateral tending cataphyllous shoots. Culms 35-75 cm tall, weakly erect, sometimes decumbent or geniculate at base, leafy, terete or slightly compressed, smooth or scabrous; nodes terete, 2-4, 1-3 exerted. Leaf sheaths compressed, keel not winged, smooth or lightly to moderately scabrous (to densely scabrous); butt sheaths papery, smooth, glabrous; flag leaf sheaths 5.8-15.2 cm long, margins fused 40-54% their length; collar margins smooth or lightly asperous, glabrous, or ciliate; ligules 1.25-3.0 mm long, abaxially scabrous or sometimes smooth; apices obtuse or sometimes acute, sterile shoot and lower culm ligules ca. 0.5-1 mm long, adaxially usually densely scabrous, apically usually densely scabrous margined; blades 2-17 cm long, 2-5 mm wide, flat or folded, margins sometimes b ecoming involute, thin to moderately thin, soft, surfaces and margins nearly smooth to moderately scabrous abaxially the keel prominent or not, adaxially prow-tipped; usually the middle culm leaves the longest (10-17 cm), flag leaf blades 34-58% their sheath in length, flag leaf blade 2.2-8.0 cm long. Panicles 7.5-20 cm long, nodding, open, sparse to moderately congested, with 25-85 spikelets, peduncles and axis sparsely to densely scabrous, proximal internode 2-4.5(-6.3) cm long; rachis with 2(-4) branches per node; primary branches spreading, flexuous, terete or weakly angled, moderately scabrous, to densely scabrous on pedicels, with coarse hooks; lateral pedicels usually 1/4-1/2 the spikelet in length, moderately to densely scabrous, prickles fairly coarse; longest branches 3-7(-11.5) cm, with 4-16(-22) spikelets, in distal 1/2, moderately crowded. Spikelets 4.2-6.5 mm long, lanceolate, laterally compressed, not bulbiferous, pale to grayish green; florets (2-)3-4, all hermaphroditic, or the distal ones pistillate; rachilla internodes terete, mostly 0.8 mm long, less than 1 mm long, smooth, glabrous; glumes narrowly lanceolate to lanceolate, unequal to subequal, usually green, distinctly keeled, keels smooth or sparsely to moderately scabrous distally, lateral veins smooth or lightly scabrous, surfaces smooth, margins narrowly scarious-hyaline, edges smooth, apex sharply acute; lower glumes 2.1-2.8 mm long, 1(-3)-veined, sometimes sickle shaped; upper glumes 2.7-3.5 mm long, distinctly shorter than lowest lemma by 0.4-0.9 mm long, 3-veined; calluses dorsally webbed, web scant or well developed, hairs 0.8-2.1 mm long, woolly; lemmas (3-)3.3-4.3 mm long, 5-veined (lowest sometimes 7-veined), lanceolate, 5-7-veined, 4.2-5.9 × longer than wide, body firmly chartaceous, grey green, with or without a anthocyanic flush just below the apex, and down the upper margin distinctly keeled, keels sparsely to moderately scabrous distally, keels for 1/3 to 3/4 and marginal veins 1/4-2/3, short to long villous, intermediate veins glabrous or sparsely sericate, between veins smooth, minutely bumpy or lightly scabrous, glabrous or sparely to moderately densely sericate, intermediate veins moderately prominent to prominent, margins and apex narrowly scarious, smooth or with few fine hooks, apices obtuse to acute, abruptly curved inward; paleas scabrous, keels coarsely scabrous, between keels minutely bumpy. Flowers weakly chasmogamous; lodicules 0.5-0.6 mm long, broadly lanceolate, with a slender lateral lobe above the middle; anthers 0.7-1.05(-1.25) mm long, or vestigial 0.1-0.2 mm long in distal flower(s). Caryopses 1.8-2 mm long, elliptical-fusiform in side-view, laterally compressed, light olivaceous brown, sulcus distinct, hilum 0.25 mm long, oval to elliptic, grain free or adherent to the palea. 2 n = unknown.

Distribution.

The species is found in Guatemala (Huehuetenango) and Mexico (Distrito Federal, Hidalgo, Mexico, Oaxaca, San Luis Potosí, Veracruz).

Ecology.

Poa ruprechtii occurs in upland mesic forests and openings to subalpine habitats; primarily distributed on volcanoes of central Mexico between 2200-3050 m; southward to alpine meadows in northern Guatemala between 3700-3750 m. Flowering May through September.

Specimen examined.

Mexico. Distrito Federal: Puerto de las Cruces, delegacíon de Cuajimalpa, 3100 m, 20 Jul 1980, J.Rzedowski 36739 (TAES). prope Santa Fe, E.Bourgeau 670 (MPU, LE, US-3159864 fragm. ex MPU, US-3159863 fragm. ex LE). 10 miles SW of Mexico City, 9000 ft [2740 m], 10 Aug 1947, F.A.Barkely 255, B.L.Westlund & J.B.Paxon (TAES). Hidalgo: Municipio de Mineral del Monte, La Minita, ca. 4 km al s. de la cabecera municipal, 2780 m, 13 Jul 1994, J. Praxedes-Peréz 120 (MEXU-1072096). Mexico: Municipio de Naucalpan, alrededores de Villa Alpina, 3100 m, 14 Jun 1981, J.Rzedowski 37312 (TAES). Municipio de Villa Nicolás Romero, 1 km al NW de Cahuacán, 2600 m, 21 Jul 1968, J.Rzedowski 25984 (MEXU-391678). Al sur del Nevado de Toluca, Cieneguillas de Cabcarr, Sultepec-La Puerta, 1 Aug 1981, R. Guzmán 4020 (MEXU-1072091). Municipio Huizquiluca, Rancho El Hielo, km 22 carretera Naucalpan-Toluca, 3050 m, 21 May 2001, A.Miranda et al. 577 (MEXU-1072128). Oaxaca: ca. 16 mi NE of Guelatao on highway 175 to Tuxtepec, 2800 m, 16 Aug 1975, G.Davidse 9771 (MO-2935776). San Luis Potosí: near Puerta Huerta in the Sierra de Alvarez, 2200-2400 m, 4 Sep 1954, E.R.Sohns 1039 (TAES, US-2154373). Veracruz: See type of Poa sharpii above.

Discussion.

In 2005 the first author viewed the type collection of Poa ruprechtii at W and (regrettably) annotated it as " Poa orizabensis Hitchc.?" At that time there was no notation on this specimens indicating it was the type of Poa ruprechtii . Subsequent searches for the type at W by Bruno Wallnöfer, and other curators where C. Heller material from Mexico might exist (IB, K, LE, WU), did not relocate this collection until 2011. Thanks to the attentive eyes of Lia Pignotti (W), the type was rediscovered at W in the Poa orizabensis folder. The type was originally determined as Poa annua L. That epithet and author were then crossed out and replaced by Poa flexuosa Muhl. ( Fig. 16 ; see discussion of Poa flexuosa under Poa palmeri ). Heller collected on the north slopes of Volcán Toluca between August 10-14, 1846, near Hacienda Cocustepec above the "small hamlets San Buenaventura and Cacalomacan" ( Heller and Rugeley 2007; an English translation of Heller’s travel’s in Mexico, originally published in German). The type locality for Poa sharpii , "El Puerto, 7700 ft" in Veracruz, is somewhere above the city of Orizaba on the southeast side of Volcán Orizaba. The species should also be searched for on or about the slopes of Volcán Orizaba in Puebla.

Specimens previously identified as " Poa ruprechtii " from Coahuila and Nuevo León, by Hitchcock (1913) and others, belong to Poa palmeri (see discussion under that species). Espejo Serna et al. (2000) and Dávila Aranda et al. (2006) accepted Poa ruprechtii s.l. and Poa sharpii . Beetle (1987) attempted to resolve the disposition of the northern plants by placing them in Poa nervosa (Hook.) Vasey. References to the name and material of Poa ruprechtii s.l. were simply left out of the volume of Beetle’s treatises on the grasses of Mexico that included Poa ( Manrique-Skendzic 1999). The description of this species given here is based on the material from Mexico cited above. The name Poa venosa Swallen has been applied to this taxon in Guatemala, the type of which is a fairly robust specimen of the species, with lemmas quite hairy between the veins. However, other specimens from Guatemala to which that name has been applied are quite variable and approach Poa orizabensis . Poa ruprechtii differs from Poa orizabensis by having lemmas that are distinctly short villous on the keel and lateral nerves and sometimes puberulent between the nerves, versus lemmas that are glabrous or very sparsely puberulent on the base of keel and sometimes the marginal vein, and glabrous elsewhere. Also the glumes in Poa ruprechtii are narrower in proportion to their length, and the spikelets are less compact than in Poa orizabensis . However, a few specimens display intermediate combinations of characteristics in Mexico (see notes on Poa orizabensis specimens cited).

Poa ruprechtii approaches Poa talamancae R.W. Pohl (Type from Costa Rica, Prov. de Cartago: 83 km from San José on the Pan American Highway, Asuncion (summit of Cerro de la Muerte), open windswept subparamo, 3335 m, 22 Jul 1966, S.Mori 214 & R.Anderson (holotype: ISC-324356!; isotypes: LE!, WIS!). However, more study is needed here also.

Figures

Figure 13. A-D Poa mulleri Swallen A spikelet B floret C palea D pistil E-H Poa seleri Pilg. E spikelet F floret G palea H pistil I-L Poa scaberula Hook. f. I spikelet J floret K palea L pistil M-O Poa orizabensis Hitchc. M spikelet N floret O palea P-R Poa ruprechtii Peyr. P spikelet Q floret R palea. A-D drawn from Beaman 4470 E-H drawn from deKoninck 134 from Guatemala I-L drawn from Peterson 11087 et al M-O drawn from Soreng 3314 & Soreng P-R drawn from Davidse 9771.

Figure 16. Poa ruprechtii Peyr. Photo of holotype collection (Heller 312).