Amoana Leopardi & Carnevali, 2012

Leopardi, Carlos, Carnevali, Germán & Romero-González, Gustavo A., 2012, Amoana (Orchidaceae, Laeliinae), a new genus and species from Mexico, Phytotaxa 65 (1), pp. 23-35 : 29-30

Amoana Leopardi & Carnevali , gen. nov.

Generi Alamaniae La Llave & Lex. affinis sed differt planta caespitosa majore, pseudobulbis fusiformibus ad apicem 2–3-foliatis, inflorescentia longipedunculata, floribus majoribus roseis, callo in unguine atque basi lobi mediani appendiculis duobus acutis digitiformibus ascendentibus et divergentibus praedito, columna arcuata sine auricula.

Type: ⎯ Epidendrum kienastii Reichenbach (1887) .

Etymology: ⎯ Amoana honors the AMO Herbarium (AMO), formerly associated with the Asociación Mexicana de Orquideología, A. C., an unparalleled resource for studies of the orchid flora of Mexico.

Amoana kienastii (Rchb.f.) Leopardi & Carnevali, comb. nov. ( Figs. 1E–H , 3C–D ); Basionymn: Epidendrum kienastii Reichenbach (1887) .

Type: ⎯ MEXICO. Without locality, Kienast-Zölly s.n. (holotype: Reichenbach Herbarium 648, W!) .

Homotypic synonym: Encyclia kienastii (Rchb. f.) Dressler & Pollard (1971: 437).

Pseudobulbs loosely clustered, narrowly fusiform, stalked, 5.0–15.0 × 0.8–1.2 cm. Leaves usually 3(2) per pseudobulb, elliptic-oblong to lanceolate, acute, 6.0–16.0 × 1.3–4.0 cm. Inflorescence 10–37 cm long, simple and bearing 4–5 flowers or, in more robust specimens, paniculate with (1–)2–3 branches, these bearing 3–5 flowers, individual branches 4–12 cm long, the terminal section only somewhat longer than the branches; peduncle with 3–5 internodes, clothed by tubular, eventually scarious sheaths 4–7 cm long, narrowly triangular-lanceolate, acute; branches subtended by sheaths similar to those of the peduncle but smaller. Floral bracts 0.50–1.00 × 0.10–0.25 cm, linear-lanceolate, relatively conspicuous (1/3–1/2 the length of the pedicellate ovary), spreading, papyraceous upon drying. Flowers pale rose-pink, the lip with three dark veins; sepals lanceolate, acute, 2.0–2.5 × 0.3–0.4 cm; petals linear-oblanceolate, acute, slightly falcate, 2.0–2.3 × 0.3–0.4 cm wide; lip basally adnate to the column (about 1/3 of its length), trilobed, total length 1.9–2.5 cm; lateral lobes spatulate-oblanceolate, somewhat falcate, apex truncate and obliquely sub-acute, 1.10–1.30 × 0.06–0.10 cm wide in its base, 0.3–0.4 cm wide near its apex; midlobe clawed, oblong-obovate, acute, 1.3–1.5 × 0.6–0.8 cm, margins somewhat undulate apically; callus on the claw and base of midlobe, oblong, distantly forming 2 acute, ascending, finger-like processes, midlobe with 5 keeled veins; column slender, clavate, sharply bowed in the middle, ca. 1 cm long, middle tooth obtuse, denticulate, shorter than the lateral teeth, which are surpassed by the anther. Capsule ellipsoid, about 18 mm long, 7 mm wide.

The holotype of Epidendrum kienastii bears an annotation label incorrectly identifying it as the holotype of Ponera kienastii Reichenbach (1877: 126) , a species described ten years earlier and currently referred to an unrelated genus, Homalopetalum Rolfe (1896 : pl. 2461).

Additional specimens examined: ⎯ MEXICO. Without locality, May 1890, Kienast-Zölly s.n. ( K!) ; Oaxaca: San Juan Lanchao, south of Puerto Portillo , 1836 m, 10 April 1972, Pollard A-186a-45 ( MEXU!) ; Pochutla, San Miguel del Puerto , 1875 m, 27 March 2006, Vásquez et al. 91 ( MEXU!) ; Pochutla, San Miguel del Puerto , 1762 m, 22 March 2006, Pascual 1815 ( MEXU!) ; Pochutla, San Miguel del Puerto , 1780 m, 16 April 2004, Velasco et al. 501 ( MEXU!) ; km 182 Puerto Escondido Highway , 1836 m, 25 April 1973, Pollard B-186a-45 ( MEXU!) ; Camino Oaxaca-Puerto Escondido , 21 May 1978, Stewart 123 ( AMO!) ; without locality, 14 May 2009, Pascual 2229 ( SERO!) .

Distribution and Ecology: ⎯Endemic to Oaxaca, Mexico, in transitional cloud forests between evergreen tropical forests and wet Quercus -Pinus forests on the Pacific slopes of the Sierra Madre del Sur at 1500–1900 m ( Fig. 2 ).

Conservation status: ⎯This species seems to be rare, and it is known from only a handful of collections. Mexican conservation law considers this species protected and “in danger of extinction” (sub Encyclia kienastii ; SEMARNAT, 2010: 51). Below follow the IUCN and MER conservation assessments.

IUCN Conservation assessment:⎯ EN. Amoana kienastii meets criteria B1a and B2a of the IUCN. It is known from four localities, its extent of occurrence is of less than 310 km 2, and its area of occupancy is less than 20 km 2. The habitat of the species is fragmented due to anthropogenic activities (mainly milpa agriculture), and it is also fragmented due to the elevational preferences of the species, which makes available for occupancy only limited portions of an apparently continuous habitats in a rugged terrain within a narrow belt (1500–1900 m). None of the known populations occurs in a protected area.

MER Conservation assessment:⎯ P (in danger of extinction). Amoana kienastii is known from four localities restricted to the Sierra Madre del Sur (near San Miguel del Puerto), thus occurring in less than 5% of the Mexican territory. According to collectors and based upon the few collections available (all consisting of a single set), this species grows at low population densities. Upon assessing the conservation status of this taxon against MER criteria, it scores 12 points (a taxon with a score of 12–14 is considered endangered).

Figures

FIGURE 1: Comparison between Alamania punicea (A–D), Amoana kienastii (E–H), Encyclia adenocaula (I–M) and Oestlundia luteorosea (N–Q). The first row (A, E, I, N) shows sepals and petals, the second (B, F, J, O) the lip; note the digitiform process in E. kienastii. The third row (C, G, K, P) shows side views of the columns and lips (partially); the fourth row (D, H, M, Q) depicts the habits, showing vegetative and reproductive shoots in A. punicea. A–D, based on Domínguez 87; E–H, based on Vasquez et al. 91; I–M, based on Soto-Núñez & Solórzano 12773A; N–Q, based on Steyermark 37609.

FIGURE 2: Distribution of Alamania punicea, Amoana kienastii, Oestlundia cyanocolumna, O. luteorosea (in part), and O. tenuisiima. We only take into account some Mexican and Central American specimens.

FIGURE 3: Amoana. A–B. Amoana latipetala. B. Drawing of sepals, petals, and lip. C–D. Amoana kienastii. C. Flower. D. Lateral view of the labellum and column; note two digitiform processes just behind the column. A–B, based on the holotype; C–D, from E. Greenwood Archive at AMES.