Stelis kaiae R.Solano & C.Dietz, 2014

Stelis kaiae R.Solano & C.Dietz , sp. nov. ( Figs. 2 View FIGURE 2 , 4B View FIGURE 4 )

Stelis with elongate, stout stems, subsessile, elliptic leaves, folious spathaceous bract, raceme multi-flowered, much longer than the leaf, greenish, star-like flowers, ovate, 7-veined sepals with revolute margins, transversely elliptic petals, and obovateoblong lip.

Type:— MEXICO. Chiapas, Municipio La Trinitaria, area behind Lagos de Montebello on road to the Selva Lacandona , temperate rain forest, 1600 m elev., December 2008, Dietz 12401 (holotype OAX!, isotype AMO!) .

Epiphytic, erect, caespitose herb, up to 38 cm tall including inflorescence. Roots flexuose, whitish. Stems unifoliate, terete, thickened toward apex, 11–14 cm long, 3.0– 3.5 mm in diameter, formed by two internodes, almost completely covered by narrow, scarious, tubular, obtuse, carinate, mucronate sheaths, inflated toward apex, with an annulus at 2.2–2.4 mm below the apex. Leaf erect to deflexed, elliptic, rounded, shortly bilobed at apex, with a minute mucro between lobules, blade slightly channeled, axially carinate, attenuate and conduplicate at base but not in a well-defined petiole; 13.8–15.0 × 4.2–5.5 cm. Inflorescence arising from annulus of stem, racemose, erect, longer than leaf, up to 24 cm long, peduncle terete, green, glabrous, 5 cm long, 2.3–3.0 mm in diameter, enclosed at base by a conduplicate, acute, scarious, carinate, spathaceous bract, 4.0– 4.5 mm long, provided with two or three bracts similar to floral bracts, tight, 4.75–4.85 mm long, the lower one hidden within the spathaceous bract; rachis elongate, flexuous, with 60–76 flowers arranged in two opposite rows, first opening at the base but simultaneously in flower. Floral bracts funnel-shape, narrow, broadly obtuse, apiculate, carinate, 2.25–4.40 mm long. Flowers extended, star-like, disposed at a right angle to rachis, 5.5–9.3 mm long, 3.5–5.2 mm wide, progressively smaller from base to apex, sepals and petals green and column and anther yellow. Ovary arching, subterete, thickened toward apex, glabrous, 2.2–3.0 mm long, 0.75–0.85 mm in diameter, articulate to a pedicel, 1.0– 2.8 mm long, 0.6 mm in diameter, arching to apex. Sepals shortly connate at base by 1.0– 1.4 mm to form a basal tube that houses the petals, lip, and column, then extended, inflexed, convex, with margins strongly revolute, minutely glandular-pilose on the adaxial surface; dorsal sepal ovate, obtuse, seven-veined, 3.2–3.5 × 3.1–3.8 mm; lateral sepals obliquely ovate, obtuse, minutely mucronate, three-seven-veined, 3.0–4.8 × 2.4–2.8 mm long. Petals erect, slightly overlapping each other above column, concave, thickened at middle, transversely elliptic, broadly obtuse to rounded, attenuate toward base, granulose-crystalline along apical margin, three-veined, 1.4–1.7 × 0.8– 1.0 mm long. Lip obovate-oblong, rounded, truncate at base, three-veined, 0.9–1.0 × 0.9–1.0 mm; deeply excavate toward apex (glenion), the cavity delimited by a pair of approximate mammillate calli and a M-shaped callus that extends toward base. Column erect, broadened toward apex, narrowed near middle, apparently trilobed from above, footless, slightly carinate along dorsal surface, 0.95–1.10 mm long, 1.50– 1.40 mm wide; clinandrium trilobed and covering base of anther, stigma formed by two apical, erect lobes, with receptive surface perpendicular to column axis, shortly projected laterally, rostellum apical, laminar, triangular, erect after removal of anther, anther apical, incumbent, ovoid-cordiform, 0.5–0.6 mm long and wide, incompletely divided inside by a pair of septa, pollinarium consisting of two obovoid, oblique, yellow pollinia, 0.45 mm long and united to elastic and translucent caudicles. Capsule not seen.

Distribution and habitat:— Mexico and possibly Guatemala. In Mexico it has been identified in only two localities, the Central Plateau of Chiapas and the high Lacandon Forest ( Fig. 5 View FIGURE 5 ). The species grows as an epiphyte in rain forests, 700–1600 m; plants have also been seen on trees within coffee farms established in this habitat.

Phenology:— In cultivated plants, flowering June to January, but most frequently October to December.

Etymology:— Named after Kaila Mahana Dietz Sagastume, daughter of one of the authors of this species.

Additional specimen examined:— MEXICO. Chiapas: municipio Chilon, Ramosil , in coffee farm derived from low mountain rain forest, December 2012, Hernandez s.n. ( OAX!) .

Comments:— The combination of subsessile and elliptic leaf, foliaceous and spathaceous bract, long raceme with green, star-like flowers, and sepals with revolute margins is unique among Mexican Stelis species. Stelis magachlamys ( Schlechter,1923: 108) Pupulin (2002: 74) is similar in habit, but it has a stouter peduncle, fewerflowered raceme, and different flowers. On the other hand, Stelis vespertina R.Solano & Soto Arenas (1993: 107) is similar, but it differs in its narrower leaves, well-defined petiole, and more extended flowers when they are fully opened ( Solano, 1993). For a long time this species went unnoticed by botanists and was only recently discovered in an area that has been well explored and studied.

Conservation status:— Not evaluated by the IUCN Red List or the Method of Evaluation of Extinction Risk for wild species of Mexico. Currently the species is only found in two localities in Mexico. Although they are areas intended for biological conservation, the Montebello Lagoons National Park and the Montes Azules Biosphere Reserve, both have been affected by agriculture and intensive livestock practices, an increase in human settlements, and recently, the severe effects of climate change ( Soto Arenas et al., 2007). The forests of Montebello Lagoons were almost totally burned in late 1990, and although they are currently recovering, problems of land tenure and the extraction of wild plants for illegal trade prevail.