Laelia halbingeriana Salazar & Soto Arenas, 2014

Salazar, Gerardo A., Jiménez-Machorro, Rolando, Huerta, Héctor M. & Hágsater, Eric, 2014, A new species and a new natural hybrid of Laelia (Orchidaceae) from Oaxaca, Mexico, Phytotaxa 178 (1), pp. 161-170 : 162-167

Laelia halbingeriana Salazar & Soto Arenas , sp. nov. ( Figs. 1 , 2 D−F).

Similar to Laelia superbiens Lindl. , but differing in the proportionately shorter, stouter pseudobulbs, low, entire, distally white keels of the labellum and obscurely bilobed anther.

Type:— MEXICO. Oaxaca: Portillo de Coyula , unos 2 km antes del poblado de Coyula subiendo desde Quiotepec, donde la línea eléctrica cruza el camino, 1,160 m elevation, collected 11 July 2004, pressed in cultivation 17 October 2006, Salazar et al. 6695 (Holotype MEXU!) .

Epiphytic herb 40−60 cm tall excluding the inflorescence. Roots simple, produced from the nodes of the rhizome, white or greyish, 1.4−3.1 mm in diameter. Rhizome conspicuous, made up of 4−5 internodes, 4−7 cm long between consecutive pseudobulbs, 1.5−2.5 cm in diameter; internodes covered when young by adpressed, tubular, obtuse, scarious sheaths, these at first straw yellow but turning blackish with time and then falling off. Pseudobulbs 15−41 cm long, 3−4.2 cm wide above the middle, fusiform, stipitate, slightly compressed laterally, made up of 4−5 internodes, often sulcate longitudinally; internodes partially covered by scarious sheaths 7−14 cm long, whitish but often turn blackish brown and eventually disintegrate (after 2−3 years). Leaves two per pseudobulb, 15−29 × 5−9 cm, rigidly coriaceous, oblong-lanceolate to oblong-elliptic, carinate, rounded and shortly apiculate at apex, conduplicate at the cuneate base. Inflorescence 48−70 cm long, from the new, mature pseudobulb, apical, erect to erect-arcuate, racemose, long-pedunculate; peduncle subterete, 27−50 cm long, 4.5−11 mm in diameter, without basal spathe but provided with strict, tubular, scarious, obtuse to acute bracts 8−9 cm long, which cover most part of the internodes; raceme up to 30 cm long, with 6−13 flowers, these simultaneous and arranged in a spiral. Floral bracts 5−10 cm long, up to 2.5 cm wide, spreading, herbaceous to scarious at anthesis, greenish-yellow, oblong-elliptic, acuminate, margins involute. Flowers showy, resupinate, odourless, sepals and petals lilac with reticulate magenta veining, labellum deep magenta with the centre yellow and provided with radiating dark purple veins, column green with purple lines and dots; dorsal sepal 6.4−8.2 × 1.2−1.7 cm, linear-elliptic, acute, margins waved; lateral sepals 6−8 × 1.3−1.6 cm, lanceolate-falcate, acute, margins waved; petals 6−8 × 1.1−1.5 cm, lanceolate-falcate, acute, somewhat clawed, conspicuously arcuate and positioned in a horizontal plane, margins waved; labellum 4.3−4.5 cm total length, 3.4−3.8 cm wide across the lateral lobes, adnate at base to the base of the column for ca. 4 mm, arcuate, deeply three-lobed; lateral lobes 2.4−3.3 × 1.2−1.8 cm, in natural position vertical at each side of the column, obliquely ovate, rounded, undulate, when spread out without distinct sinuses separating them from the mid-lobe; mid-lobe 1.6−2.3 × 1.6−2.3 cm, orbicular to shortly elliptic, rounded and inconspicuously apiculate, margins waved, callus consisting of 7 low keels running from the base of the labellum to about the middle of the mid-lobe, where they are more prominent (2−3 mm tall); column 2.6−2.8 cm long, 7.2−9 mm wide near the apex, oblong, slightly arcuate, trigonous, ventrally concave, provided at base with an excavation (cunniculus) that penetrates the apex of the ovary for ca. 5 mm but lacks nectar; anther 4−6 × 4−5 mm, ventral, subquadrate, slightly bilobed, white; rostellum retrorse, rounded, provided on the internal surface with a lunate viscarium; pollinarium ca. 4 mm long and wide, made up of 8 laterally compressed, obliquely ovate, yellow pollinia arranged in two rows and attached to yellow granular caudicles; ovary 5.3−7 cm long, 4.5–5 mm in diameter near the apex, subterete, twisted, provided with three longitudinal ribs above the middle, these with winged, undulate margins. Capsule 65 mm long including the 10 mm long apical beak, 30 mm in diameter, ellipsoid, pale green, with three sulcate ribs alternating with three rounded ribs, pedicel 45 mm long, 3.5 mm in diameter.

Distribution and ecology:—Endemic to Mexico and known only from the Sierra Madre Oriental in northern Oaxaca ( Fig. 4 ). Epiphytic, in tropical semi-deciduous forest, Quercus forest, moist Pinus-Quercus forest and mountain rain forest, from 800 to 2,000 m elevation.

Etymology:—The specific epithet honours the late Federico Halbinger, Mexican orchid student and life-long member of the Asociación Mexicana de Orquideología, who made seminal contributions to the taxonomy of the genera Rhynchostele Reichenbach (1852: 770) , Barkeria Knowles & Westcott (1838: 7–8) and Laelia .

Phenology:—Flowering has been observed in the field in late October and early November; in cultivation from October to December.

Conservation status:—According to the MER, which evaluates four main criteria (characteristics of the geographic distribution, characteristics of the habitat, intrinsic biological vulnerability and impact of human activities), L. halbingeriana qualifies as a species “subject to special protection”, a category that includes “those species that could be endangered by factors that influence negatively their viability, for which it is required to propitiate their recovery and conservation, or the recovery and conservation of populations of associated species” ( SEMARNAT 2010). Following the IUCN Red List Criteria and Categories ( IUCN 2012), L. halbingeriana should be considered as “endangered” according to criterion B 1, since extent of occurrence is estimated to be <5,000 km 2, besides the fact that the modelled distribution area has been severely fragmented and reduced (the actual surface was estimated as 1,826 km 2, taking as basis the consensus model but considering only those areas suitable for the presence of the species, i.e. in which tree cover has not been eliminated by human activities; see Huerta 2014). Several populations are located within the Tehuacán-Cuicatlán biosphere reserve, which confers them some degree of protection, although the most accessible populations, such as those near Coyula and El Faro, have been subjected to a certain amount of extraction of plants from orchid growers, and the species is moderately common in cultivation in Mexico. Moreover, local peasants of the village of Coyula have been observed collecting the inflorescences of L. halbingeriana to adorn their homes and altars during the celebrations of All Saints and the Day of the Death (November 1th and 2nd; G. A. Salazar pers. obs.; Salazar et al. 2006). It is not known to what extent these extractive activities may be affecting the natural populations.

Additional specimens examined:— MEXICO. Oaxaca: Sierra de Cuicatlán, Portillo de Coyula , 1,450 m, collected 23 September 1937, pressed in cultivation 30 October 1937, Conzatti sub Östlund 7074 ( MO!, drawing AMO!) ; Coyula, collected 1 June 1996, pressed in cultivation January 2007, Guzmán sub Soto 7934 ( AMO!) ; Portillo de Coyula, unos 2 km antes del poblado de Coyula subiendo desde Quiotepec , donde la línea eléctrica cruza el camino, 1,160 m elevation, collected 24 October 2004, pressed in cultivation 13 December 2011, Salazar et al. 6740 ( AMO!, MEXU!, SERO!) ; same locality, collected 11 July 2004, pressed in cultivation 28 October 2011, Jiménez et al. 2463 ( AMO!) ; near Teopoxco, ENE of Teotitlán del Camino , cultivated in Oaxaca, A. Jones s.n. ( AMO!) ; San Juan Bautista Cuicatlán, cañada, 10 km al E de Quiotepec , 1,240 m, 6 December 1993, Salas 612 ( AMO!) ; cerca de El Faro, ca. 1,000 m elev., collected 13 May 2006, pressed in cultivation 7 November 2011, Salazar et al. 7208 ( MEXU!) .

Discussion:—As already mentioned, L. halbingeriana is similar in overall appearance to L. superbiens , which is most probably its sister species. However, the former can be distinguished from the latter by the proportionally shorter, stouter pseudobulbs, the low, entire keels of the labellum, which are white at their apices (vs. prominent, waved and entirely yellow) and the anther obscurely bilobed (vs. prominently bilobed, with the appearance of a cloven hoof; Fig. 2 A−F). Our distribution models indicate differences in the environmental conditions preferred by L. halbingeriana and L. superbiens , since, in spite of a small area of predicted distribution for L. superbiens in northern Oaxaca, field exploration in the area ( G. A. Salazar, pers. obs.) and previous monographic work ( Halbinger and Soto 1997) demonstrate that genuine L. superbiens does not occur there. In fact, most of the predicted distribution for L. halbingeriana does not overlap with the potential distribution of L. superbiens ( Fig. 4 ). Such apparent habitat differentiation supports the morphological criteria (see earlier) on which we differentiate the two species.

Figures

FIGURE 1. Laelia halbingeriana. A. Flowering plant. B. Flower. C. Labellum and column from side. D. Dorsal sepal. E. Petal. F. Lateral sepal. G. Labellum. H. Column, ventral view. I. Column apex, ventral view after removal of the pollinarium. J. Ovary and column, longitudinal section. K. Anther. L. Pollinarium. Drawn by Rolando Jiménez-Machorro from Guzmán sub Soto 7934.

FIGURE 2. Taxa of Laelia discussed in the text.A–C. Laelia superbiens (Chiapas, Miller s.n., AMO).A. Flower. B. Close-up of labellum and column. C. Ventral view of column apex. D–F. Laelia halbingeriana (Oaxaca; D–E from Salazar et al. 6695; F from Jones s.n.). D. Flower. E. Close-up of labellum and column. F. Ventral view of the column apex. G. Flowers of Laelia anceps (Oaxaca, Salazar et al. 6685). H. Flower of Laelia ×oaxacana (Oaxaca, Lau sub Hágsater 9359). Photographers: Eric Hágsater (A, B); Edward W. Greenwood (C, F); Gerardo A. Salazar (D, E, G); Rolando Jiménez-Machorro (H).

FIGURE 4. Distribution of Laelia anceps, L. halbingeriana, L. superbiens and L. ×oaxacana. Symbols indicate point locality records of each species; colours indicate potential distribution areas according to the best models obtained with GARP (see text).