Poa glycerioides Rupr., nom. nud.). Discussion. We have seen a few specimens from Guatemala that are tentatively placed here but verge on the limits accorded to P. ruprechtii: Huehuetenango, San Juan Ixcoy, ca. del cruce para Chanchocal, 3200 m, J. Rios 6229, N. Hernandez M. Veliz (MEXU), Sierra de los Cuchumatanes, at km 311 on Ruta National 9N (between Paquix and Chemal, ca. 3360 m, 2 Aug 1959, J.H.Beaman 3011 (MO, US, US “P. atala” ined.). Also reported from Huehuetenango are J.H.Beaman 3799b (US), and J.Rios s.n., N.Hernandez M.Veliz (MEXU). Poa orizabensis and P. ruprechtii are difficult to separate when lemma pubescence is scantly developed in the latter, but as interpreted here the former has broader glumes and more compact spikelets, and the sides of the lemmas are glabrous. Further study is needed.15. Poa palmeri Soreng P.M. Peterson, sp. nov. urn:lsid:ipni.org:names:77121282-1 http://species-id.net/wiki/Poa_palmeri Figs 6J, 15 Type: Mexico. Nuevo Le , Sierra Madre [Oriental] above Monterey [ca 25?8’N, 100?8’W], calcareous ledges, 3000 ft [misprint for 8000 ft; 2440 m], 31 Mar 1906, C.G.Pringle 10212 (holotype: US-462254!; isotypes; GH!, MEXU539725!, MO-1770420!, MSC, NMC!, NY-431382!, WYAC). Diagnosis. Differing from Poa ruprechtii Peyr. by leaf collar margins flared (AM152MedChemExpress BMS-986020 versus not flared), ligules of upper culm leaves truncate (versus obtuse to acute), flag leaf sheaths fused by an invaginated hyaline membrane for much of the upper fusion length (versus abruptly fused by firmly chartaceous margins), spikelet pedicles elongated and moderately to densely scabrous (versus shorter and usually densely to more coarsely scabrous), distal rachilla internodes usually 1? mm long (versusRobert J. Soreng Paul M. Peterson / PhytoKeys 15: 1?04 (2012)less than 1 mm), lemmas thinly chartaceous, intermediate veins faint to moderately prominent, not extending to near the upper margin, margin and apex fairly broadly scarious-hyaline (versus lemmas chartaceous, intermediate veins prominent, extending nearly to the margin, margin and apex narrowly scarious), anthers 1.6?.8 (versus 0.7?.05[?.25]) mm. Description. Trioecious (mostly hermaphroditic, but some pistillate or staminate). Perennials; tufted, sometimes sub-rhizomatous to rhizomatous, tufts dense to loose, generally medium girth and height, green or bluish-grey-green; tillers extravaginal (basally cataphyllous), and/or mainly intravaginal (each subtended by a single elongated, 2-keeled longitudinally split prophyll), with lateral or downward tending, cataphyllous shoots, or without them. Culms (26?50?0 cm tall, erect or bases slightly decumbent, fairly slender, not branching above the base, leafy, terete or weakly compressed, smooth; nodes 3?, terete or slightly compressed, 1? exerted. Leaf sheaths slightly compressed, RG7666 side effects smooth or sparsely to infrequently densely scabrous, glabrous or rarely retrorsely hirtellous to strigulose; butt sheaths papery, smooth, glabrous; flag leaf sheaths (5?7?8 cm long, margins fused 34?5 the length, fused by an invaginated hyaline margin for much of that length, 1.1?.1 ?longer than its blade; collar margins of lower and mid culm leaves usually flared, smooth or scabrous, glabrous or more often ciliate; ligules 0.8? mm long, scarious to hyaline, adaxially scabrous or puberulent, upper margins often ciliolate, apices truncate and entire below to obtuse and irregularly dentate/lacerate above, sterile shoot ligules like those of the culm leaves; blades 2?0 cm.Poa glycerioides Rupr., nom. nud.). Discussion. We have seen a few specimens from Guatemala that are tentatively placed here but verge on the limits accorded to P. ruprechtii: Huehuetenango, San Juan Ixcoy, ca. del cruce para Chanchocal, 3200 m, J. Rios 6229, N. Hernandez M. Veliz (MEXU), Sierra de los Cuchumatanes, at km 311 on Ruta National 9N (between Paquix and Chemal, ca. 3360 m, 2 Aug 1959, J.H.Beaman 3011 (MO, US, US “P. atala” ined.). Also reported from Huehuetenango are J.H.Beaman 3799b (US), and J.Rios s.n., N.Hernandez M.Veliz (MEXU). Poa orizabensis and P. ruprechtii are difficult to separate when lemma pubescence is scantly developed in the latter, but as interpreted here the former has broader glumes and more compact spikelets, and the sides of the lemmas are glabrous. Further study is needed.15. Poa palmeri Soreng P.M. Peterson, sp. nov. urn:lsid:ipni.org:names:77121282-1 http://species-id.net/wiki/Poa_palmeri Figs 6J, 15 Type: Mexico. Nuevo Le , Sierra Madre [Oriental] above Monterey [ca 25?8’N, 100?8’W], calcareous ledges, 3000 ft [misprint for 8000 ft; 2440 m], 31 Mar 1906, C.G.Pringle 10212 (holotype: US-462254!; isotypes; GH!, MEXU539725!, MO-1770420!, MSC, NMC!, NY-431382!, WYAC). Diagnosis. Differing from Poa ruprechtii Peyr. by leaf collar margins flared (versus not flared), ligules of upper culm leaves truncate (versus obtuse to acute), flag leaf sheaths fused by an invaginated hyaline membrane for much of the upper fusion length (versus abruptly fused by firmly chartaceous margins), spikelet pedicles elongated and moderately to densely scabrous (versus shorter and usually densely to more coarsely scabrous), distal rachilla internodes usually 1? mm long (versusRobert J. Soreng Paul M. Peterson / PhytoKeys 15: 1?04 (2012)less than 1 mm), lemmas thinly chartaceous, intermediate veins faint to moderately prominent, not extending to near the upper margin, margin and apex fairly broadly scarious-hyaline (versus lemmas chartaceous, intermediate veins prominent, extending nearly to the margin, margin and apex narrowly scarious), anthers 1.6?.8 (versus 0.7?.05[?.25]) mm. Description. Trioecious (mostly hermaphroditic, but some pistillate or staminate). Perennials; tufted, sometimes sub-rhizomatous to rhizomatous, tufts dense to loose, generally medium girth and height, green or bluish-grey-green; tillers extravaginal (basally cataphyllous), and/or mainly intravaginal (each subtended by a single elongated, 2-keeled longitudinally split prophyll), with lateral or downward tending, cataphyllous shoots, or without them. Culms (26?50?0 cm tall, erect or bases slightly decumbent, fairly slender, not branching above the base, leafy, terete or weakly compressed, smooth; nodes 3?, terete or slightly compressed, 1? exerted. Leaf sheaths slightly compressed, smooth or sparsely to infrequently densely scabrous, glabrous or rarely retrorsely hirtellous to strigulose; butt sheaths papery, smooth, glabrous; flag leaf sheaths (5?7?8 cm long, margins fused 34?5 the length, fused by an invaginated hyaline margin for much of that length, 1.1?.1 ?longer than its blade; collar margins of lower and mid culm leaves usually flared, smooth or scabrous, glabrous or more often ciliate; ligules 0.8? mm long, scarious to hyaline, adaxially scabrous or puberulent, upper margins often ciliolate, apices truncate and entire below to obtuse and irregularly dentate/lacerate above, sterile shoot ligules like those of the culm leaves; blades 2?0 cm.