Poa reclinata (Swallen) Soreng & P.M. Peterson, 2016

Peterson, Paul M. & Soreng, Robert J., 2016, A revision of Poa subsection Aphanelytrum (Poaceae, Pooideae, Poaeae, Poinae); and a new species, Poa auriculata, PhytoKeys 63, pp. 107-125 : 112-114

Poa reclinata (Swallen) Soreng & P.M. Peterson comb. nov. Fig. 3

Festuca reclinata Swallen, Contr. U.S. Natl. Herb. 26(6): 254. 1949.

Type.

COLOMBIA. Departamento Santander, Cordillera Oriental, Paramo de Almorzadero, 3500-3700 m, 20 Jun 1940, J. Cuatrecasas & H. Garcia Barriga 9970 (holotype: US-1798714!; isotypes: BC-635144 seen digitally!; COL-34839 seen digitally!).

Description.

Stooling perennials forming small tussocks with intravaginal innovations. Culms 30-40 cm tall, decumbent to erect, often weak, spreading to prostrate, culm bases continuously branch and often root at low to mid-culm nodes, glabrous; nodes 2 or 3 in distal half; internodes 1.4-8.0 cm long. Leaf sheaths about 2/3 as long as the internodes, membranous, greenish-white, scabrous, upper sheaths open 1/2 the length, collars flared; ligules 1-2.5 mm long, membranous, apex acute, ephemeral; blades 5-15 cm × 0.3-0.5 mm, flat, thin, lax, green, abaxially scabrous. Panicles 9-10 × 2-3 cm, few-flowered with 5-8 spikelets, flexuous, ovate, branched; branches glabrous. Spikelets 10-13 mm long, 4-flowered, glabrous; obovate; rachilla 1.2-2.4 mm long, minutely scabrous; glumes 1.3-3.6 mm long, membranous, lanceolate, green, glabrous, upper margins hairy; lower glumes 1.3-2 mm long, 1-nerved, apex acute; upper glumes 3-3.5 mm long, less than ½ as long as the florets, 3-veined, apex acuminate; lemmas 6.6-8 mm long, 5-veined, lanceolate, membranous, green, scabrous, apex bifid, two-dentate, awned between the teeth, the awn 1-2 mm long; paleas 4.6-5.2 mm long, membranous, keels scabrous, apex bifid; lodicules 0.6-0.8 mm long, lanceolate; anthers 2.7-3.3 mm long; ovaries glabrous. Caryopses not seen.

Leaf anatomy.

The leaf anatomy of Poa reclinata is C3, XyMS+ and the transverse sections have many widely spaced vascular bundles with small ribs; sclerenchyma is under both abaxial and adaxial epidermis, discontinuous, small, extending to the vascular bundles forming girders; bulliform cells are absent; epidermis is sparsely hairy. An anatomical description of Poa reclinata is also found in Watson and Dallwitz (1992) and Stančík and Peterson (2007, figs 13g, 77 c–f).

Phenology.

Flowering in July.

Distribution.

Poa reclinata is known only from the type locality, the paramo of the Colombian Cordillera Oriental, Dept. Santander ( Stančík and Peterson 2007).

Conservation status.

The species is rare and its conservation status is data deficient ( IUCN 2010).

Etymology.

The specific epithet is probably in reference to the decumbent, spreading or prostrate culms, a frequent characteristic of the species in this subsection of Poa .

Comments.

Stančík and Peterson (2007) mentioned that the spikelets and panicles of Festuca [ Poa ] reclinata were similar to Aphanelytrum procumbens [ Poa hitchcockiana ], but the glumes in the former are veined. They provisionally placed Festuca reclinata in Festuca subg. Subulatae (Tzvelev) E.B. Alexeev sect. Glabricarpae E.B. Alexeev, as suggested by Aleexev (1986), along with Festuca caldasii (Kunth) Kunth and Festuca woodii Stančík. The latter two species of Festuca have open sheaths, flattened and hairy (hispid?) rachillas, and lemmas with rounded keels and annulate calluses, whereas Poa reclinata has fused sheaths ½ their length, terete rachillas that are minutely scabrous, and lemmas with compressed keels and smooth transitions from callus to lemma. We hope to confirm the placement of Poa reclinata in Poa subsect. Aphanelytrum in future DNA studies.

Figures

Figure 3. Poa reclinata: A Habit B Sheath, ligule, and blade C Spikelet D Lower floret E Upper glumes F Lower glume G Lemma H Palea and rachilla, lateral view I Stamens with palea J Lodicules and with pistil. (Cuatrecasas 9970 & Garcua Barriga, US- 1798714).