Stelis lapinerae Soto Arenas & R.Solano, 2014

Stelis lapinerae Soto Arenas & R.Solano , sp. nov. ( Figs. 3 View FIGURE 3 , 4C View FIGURE 4 ).

Type:— MEXICO. Michoacan: Municipio de Ziracuaretiro, pedregal de San Andres Corú , bosque de encino, epífita sobre árbol seco. 19º55’57’’ N, 101º57’0.6’’ W, Septiembre 2013, Valdez s.n. ( IEB!) GoogleMaps .

Similar to Stelis ciliaris Lindl. from which it differs by its smaller plants, abbreviated stems, arching leaves, less floriferous raceme, not ciliate sepals, lateral sepals different and smaller than the dorsal one, and orbicular-obovate petals.

Epiphytic, erect, caespitose herbs, 10–13 cm tall including inflorescence. Roots flexuose, whitish, 0.8 mm in diameter. Stems unifoliate, fascicled, terete, formed by two internodes, 5–9 mm long, 1.5 mm in diameter, with an annulus 1.5 mm below apex, completely covered by tubular, scarious, obtuse, carinate, mucronate sheaths slightly widened towards the apex. Leaf channeled, arching, oblanceolate, rounded, shortly bilobed at apex, with a minute mucro between lobules, 1.5–4.0 × 0.5–0.6 cm; gradually attenuated toward base into a conduplicate petiole. Inflorescence arising from annulus of stem, racemose, erect, longer than leaf, 9.5–12.5 cm long; peduncle as long as leaf, straight, terete, 2.5 cm long, 0.7–0.8 mm in diameter, enclosed at base by a conduplicate, triangular, acute, scarious, carinate spathaceous bract, and provided with two or three bracts similar to the floral bracts, the lower one hidden within the spathaceous bract, 2.0– 2.5 mm long, rachis straight, with 9–15 flowers distichously arranged, overlapping, most flowers opening at the same time; floral bracts obliquely infundibular, obtuse, revolute at margins, 1.6 mm long. Flowers disposed at a right angle with respect to rachis, 5.6 × 3.4 mm, with red-wine sepals, petals, and column, cream-yellow at apex of petals and lip, anther yellow. Ovary obliquely obconic, subtrigonous, 0.7 mm long, 0.5 mm in diameter, articulate to a terete pedicel, as long as floral bract. Sepals fleshy, extended, convex, connate at base, fleshy, five-veined, minutely verruculose on adaxial surface, carinate along veins on abaxial surface; dorsal sepal free from the lateral ones, ovate, obtuse-rounded, 3.8 × 2.8 mm; lateral sepals different and smaller than the dorsal one, connate almost at the middle of their length, obliquely elliptic obtuse, 3.4–3.6 × 1.8–2.0 mm. Petals porrect, concave, thickened at the middle, orbicular-obovate, rounded, apically deflexed, attenuate toward base, one-veined, 0.8–1.0 × 0.9–1.0 mm. Lip arching in lateral view, thickened, minutely twoauricled at base, attached to column base by a membranous claw, orbicular-ovate, rounded, 0.9 x 0.7 mm, at the adaxial surface with an ovate cavity (glenion) delimited by a pair of approximate mammillate calli and an obtriangular callus that extends toward base. Column erect, broadened toward apex, narrowed near middle, extended ventrally at base, 0.8 mm long, 0.5 mm wide, clinandrium trilobed, covering base of anther, stigma subapical, slightly excavated, rostellum subapical, suberect, triangular, laminar, apically deflexed with removal of anther, anther apical, incumbent, transversely ovoid-ellipsoid, microscopically papillose, 0.4 × 0.7 mm, incompletely divided inside by a pair of septa, pollinarium consisting of two obovoid, oblique, yellow pollinia, 0.3 mm long, united to an elastic and translucent caudicle, this in turn embedded to a translucent drop. Capsule not seen.

Distribution and habitat: — Endemic to Mexico. It has only been found in two nearby localities within a wellbotanized region ( Fig. 5 View FIGURE 5 ). The plant grows as an epiphyte in pine-oak or oak forests within rocky areas, 1800–1900 m.

Phenology: —Flowering September–November.

Etymology: —Named after Jeanne M. de Lapiner (1913–1993), American painter who lived in Morelia. She was an amateur orchid enthusiast, who in the 1970s published an illustrated booklet titled Orquideas de Michoacan.

Additional specimens examined: — MEXICO. Michoacan: municipio Patzcuaro, Pedregal del Coru , bosque de pino-encino, epifita, Octubre 2005, Soto 10425 ( AMO!); road Uruapan-Paztcuaro , November 1970, Bashor 1917 ( AMO, photo!) .

Comments:— Stelis lapinerae was seen for the first time in the 1970s when Noble Bashor collected it near Uruapan. From these specimens are the only known photos showing an inflorescence superficially similar to Lepanthopsis : flowers perpendicular to the rachis, sepals extended to form a platform, petals and lip reduced and thickened, and apical anther. In 2005 Miguel Soto collected live specimens of this species near Paztcuaro, which flowered in cultivation. Once analyzed, it was evident that it was a new species of Stelis . The most similar species is Stelis ciliaris Lindley (1837: 353) ; however, it is differentiated by larger plants, more floriferous raceme, resupinate flowers, ciliate sepals, and because its allopatric distribution in low to moderate elevations along the slopes bordering the Gulf of Mexico ( Solano, 1993). Another similar species, at least in habit and present in that region of Michoacan, is Stelis rufobrunnea ( Lindley 1859: 217) Williams (1939: 188) , but it has a raceme with looser, smaller, and shortly tubular flowers, and differently formed petals and lips.

Conservation status: —Not evaluated by the IUCN Red List or the Method of Evaluation of Extinction Risk for wild species of Mexico. It is probably threatened because it has a restricted distribution, found only in a small rocky area of volcanic origin. Also, its habitat has recently been diminished by the expansion of avocado farms and wood extraction for handicrafts. Unfortunately, there are no natural protected areas in this region.