Barkeria uruapani C.León-Peralta, J.Valdez-Partida & E.A.Pérez-García, 2021

León-Peralta, Cekouat E., Valdez-Partida, Julio & Pérez-García, Eduardo A., 2021, Barkeria uruapani (Laeliinae, Epidendroideae, Orchidaceae), a new species from western Mexico, Phytotaxa 513 (4), pp. 282-294 : 285-289

Barkeria uruapani C.León-Peralta, J.Valdez-Partida & E.A.Pérez-García , sp. nov.

Herba epiphytica, B. barkeriola Rchb. f. adspectu similis, sed differt paniculis florescentia simultanea, floribus labello elliptico-obovato plerumque extenso, et sepalis lateralibus ab angulum 90º vel obtusum.

Type:— MEXICO: Michoacán: Uruapan Municipality, 1.5 km south of El Sabino , epiphyte in a guava orchard surrounded by tropical deciduous forest, 760 m, 4 December 2020, J. Valdez-Partida 25 (holotype: MEXU; Fig. 1 ) .

Epiphytic, compact, caespitose, erect, deciduous herb, 15–72 cm tall including the inflorescence. Roots numerous, simple or branched in the terminal part, fleshy, terete or slightly flattened when adhering to the substrate, graygreen, 2–4 mm thick. Stem slightly thickened, subterete, a little laterally compressed, 40–210 × 4–8 mm, with 3–7 internodes, covered by tight, scarious sheaths, generally mottled with reddish-purple dots and streaks. Leaves 3–6, distichous, distributed from approximately the first quarter of the stem, deciduous, slightly reflexed, articulated to the stem sheaths, leathery-fleshy, flexible, lanceolate, acuminate, dorsally carinate, olive green, sometimes speckled with red-purple, 2.7–12.5 cm × 0.7–2 mm, larger towards the apex of the stem. Inflorescence from the mature stem, apical, erect, a panicle with 1–2 branches developing simultaneously (a raceme in young plants), congested, with 2–14 flowers, up to 11 open at the same time, lateral branches with up to 4 flowers, the entire inflorescence 7–55 cm long; peduncle elongated, subterete, 1.5–3 mm thick, 6–43 cm long, green profusely speckled with purple, covered by up to 7 scarious bracts, strongly appressed, tubular, acuminate, the first overlapping, 1.5–4.8 cm long. Floral bracts concave, triangular-lanceolate, acuminate, drying prior to anthesis, papery, brown, 5–8 mm × 2-3 mm, progressively smaller, adpressed to the ovary. Flowers resupinate, very showy, odorless, 43–52 mm in diameter; tepals extended, inflexed, concave, arranged in a plane superior to the lip and column; tepals lilac-pink, slightly lighter on the inner surface, the sepals with some white spots; lip pale pink-white, with magenta lines and spots below the column, the apex with a magenta elliptical blotch; column yellow-cream to pink on both surfaces, the dorsal part with abundant purple spots and streaks on the central axis, with 2 more intense spots or bands at the apex; anther yellow-cream. Ovary pedicellate, arched to sigmoid, thin, terete, thickened distally, green profusely stained with purple, inconspicuously 6-sulcate, 14–28 mm long, ca. 1 mm thick at the pedicel and 2.5 mm at the apex. Sepals incurved, slightly concave, truncated at the base, slightly carinate on the external surface, dorsal sepal elliptic, acute, acuminate, 19–25 × 6.0– 8.7 mm. Lateral sepals elliptic-lanceolate, oblique, acute, acuminate, forming a right to obtuse angle when flattened, 26– 32 × 6–9 mm. Petals lanceolate to obovate, acute, acuminate, attenuated towards the base, approximately on the same horizontal axis, incurved and slightly concave, slightly sulcate on the inner surface, 25–29 × 8.5–10.0 mm. Lip adnate to the base of the column ca. 4–5 mm, forming an apparently dry nectary that slightly penetrates the ovary; generally elliptical to obovate, the base obtuse, the apex rounded to emarginate, occasionally acuminate, the basal margins very slightly inflexed, lateral margins extended and slightly raised, or sometimes folded downwards, the entire lip 27.0–31.5 × 18–20 mm. Ornamentations little developed, at the base of the lip formed by two thickened, flattened and fleshy keels that form a very low, narrow, sulcate, triangular-shaped basin, ending in one or two tiny teeth, followed by a very small elliptical depression; with one keel at the apex, erect 1 mm, pubescent. Column appressed against the lip, straight, dorsoventrally compressed, generally obovate-spatulate, wide due to the presence of two membranous, semi-elliptic, downward curving, revolute, smooth, thin wings, 6–7 × 2–2.5 mm, wider for the last two thirds of the column; the ventral surface very slightly sulcate, with two elliptical depressions below the wings; the entire column 10–14 mm long, 6–7 mm wide, the base 3 mm wide. Clinandrium a transversely rectangular cavity, 4 mm wide and 1.5 mm deep, the upper margin with an obtuse-rounded, inflexed middle tooth, the sides limited by 2 fleshy, erect, straightrounded lobes. Stigmatic cavity depressed, obovate-trapezoid, the lateral lobes visible in the lower half, rounded, cream-white, viscous, 3.5 × 2.0 mm. Rostelum a thick, concave, transversely semi-elliptical, cream-white lamina, ca. 2 mm wide, viscarium produced on the abaxial surface. Anther cap elliptic-cordiform, dorsoventrally compressed, slightly emarginate at the apex, the wings very little raised, without exceeding the limit of the clinandrium, 4-locular, fleshy, 2.6 × 1.6 mm. Pollinarium with 4 laterally compressed pollinia, in 2 pairs, intense yellow, obovate-semielliptical, 0.95 × 0.67 mm; united to granular caudicles glued longitudinally in pairs, the apices bulging, 1.5 mm long. Capsule not seen.

Etymology:—The specific epithet “ uruapani ” comes from the Purépecha term “urhupani”, which refers to the constant event of flowering and fructifying. This word was translated to Spanish as Uruapan and is the name of one of the municipalities where the new taxon is to be found.

Distribution:—Endemic to the state of Michoacán de Ocampo, Mexico. Known only from the northwestern portion of the Balsas River Basin ( Fig. 2 ).

Ecology:— Barkeria uruapani is an epiphytic, deciduous, perennial herb. It has been found at elevations between 760 and 850 m, in riparian forests with Enterolobium cyclocarpum ( Jacquin 1801: 30) Grisebach (1860: 226) and trees of the genera Cecropia Loefling (1758: 272) and Rapanea Aublet (1775: 121) , immersed in an area of tropical deciduous forest; it also grows on guava [genus Psidium Linnaeus (1753: 470) ] orchards, particularly those that are near to rivers ( Fig. 3 ). This orchid flowers from October to December.

Figures

FIGURE 1. Barkeria uruapani C.León-Peralta, J.Valdez-Partida & E.A.Pérez-García. A. Plant. B. Floral bract. C. Flower. D. Sepals and petals, front view. E. Sepals and petals, back view. F. Flattened lip. G. Lip and column in normal position, front view. H. Lip and column in normal position, lateral view. I. Column, front and back view. J. Column, lateral view. K. Anther cap. L. Pollinarium. M. Ovary. Plate based on the plant that served as type, photographs by J. Valdez-Partida, edition and composition by C. León-Peralta.

FIGURE 2. Distribution of Barkeria uruapani and related species.

FIGURE 3. Barkeria uruapani growing in situ at the type locality. A. Plant growing in a guava plantation. B–C. Plants growing as twig epiphytes in tropical dry forest. Photographs by J. Valdez-Partida (A, C), and G. Victoria (B).