Lockhartia tenuiflora M.A.Blanco, 2014

Blanco, Mario A., 2014, Four new species of Lockhartia (Orchidaceae, Oncidiinae), Phytotaxa 162 (3), pp. 134-146 : 142-144

Lockhartia tenuiflora M.A.Blanco , sp. nov. ( Figs. 4 , 5D–F )

Very similar to Lockhartia lepticaula Bennett & Christenson (2001 : plate 678), but with a narrower middle lobe of the labellum and with smaller (1 × 1.5 mm), triangular column wings (vs. larger [1.5 × 2 mm], flabellate column wings in L. lepticaula ).

Type:— ECUADOR. Prov. Sucumbios [actually Prov. Napo: Cantón El Chaco, Parroquia Gonzalo Díaz de Pineda ]: Road from Las Palmas to El Chaco, km. 10.9, 1777 m, 00°17’40.3”S, 77°46’22.7”W, 11 February 2004, Whitten et al. 2719 (holotype: FLAS! ; isotype: QCA! ).

Stems apparently erect, more or less rigid, 14−51 cm long when reproductive, with 38−55 leaves; shoots (stem and leaves) 10−19 mm wide. Leaves marcescent, unifacial, laterally flattened, narrowly triangular in side view, with straight to slightly incurving or outcurving margins, obtuse to rounded apically, exposed part of largest leaves 10−29 × 3−9 mm. Inflorescences both terminal and axillary from the distal half of the stem, with 1−6 flowers produced more or less simultaneously; exserted portion 1−2.5 cm long, internodes 2−5 mm long; inflorescence bracts amplexicaul, widely ovate to suborbicular, cordate, obtuse to apiculate, expanded to campanulate, 6−7 × 3−6.5 mm; pedicel and ovary 11−15 mm long. Flowers resupinate, widely open, 12−16 mm tall, yellow, the labellum with reddish brown to purplish-brown spots around the callus and on the lateral lobes, the callus mostly orange. Sepals elliptic, slightly concave, acute to obtuse, 6−6.5 × 3−3.5 mm. Petals elliptic to suboblong, round to subtruncate apically, slightly curved forward, the margins recurved, 6 × 3.5 mm. Labellum 3-lobate, 8−11 mm long, 13−15 mm wide across lateral lobes when flattened; lateral lobes elongate, narrowly oblong to sublinear, attenuate, acute, curved toward front, 5.5−6.5 × 1 mm; midlobe divided into 4 lobules, pandurate, emarginate, margin irregularly undulate, 6.5−7.5 × 5.5−6.5 mm, the basal lobules folded backwards, the distal lobules straight; callus suboblong, the base forming a concave cushion with a tuft of short, glandular hairs, 1.5 × 1.5 mm; the distal portion forming a mass of low tubercles, 3−4 × 2−2.5 mm. Column rhombic, 3 mm long, 3 mm wide; wings subtriangular, with an irregularly denticulate margin, 1 × 1.5 mm; stigmatic cavity subpandurate, 1 × 0.4 mm; anther cap galeate, 1.3 × 1 mm; pollinarium 1 mm tall, stipe bifid. Fruit (undehisced) fusiform to obovoid, 14−16 × 6−7 mm.

Phenology:— The few field collections available indicate flowering at least during the months of February, July and November. Cultivated plants are known to flower in March, August, and September.

Distribution:— Ecuador and Colombia, from 1,100 to 1,900 m on the eastern (Amazonian) side of the Andes (maybe up to 2600 m, based on Dryander 2527; see below). Expected in northern Peru (north of the Huancabamba Depression).

The two Colombian collections cited below have somewhat deteriorated flowers or no flowers at all; their identification as Lockhartia tenuiflora is somewhat tentative, and it is partly based on their vegetative morphology. However, I have seen photographs of a Colombian plant, unambiguously of L. tenuiflora , collected by William Vargas of Universidad ICESI (Cali, Colombia). Unfortunately, the voucher is stored among many thousand unmounted herbarium specimens and has not yet been located (W. Vargas, pers. comm. 2012). De Retana (1991) published another photograph of L. tenuiflora in volume 2 of Native Colombian Orchids.

Additional specimens examined: — COLOMBIA. Department unknown: West. Cordillera, Observatorio , 2600 m, September 1941, Dryander 2527 (US). Cundinamarca: Vergara, Vda. El Palmar, 1590 m, 14 June 1993, Chaparro de Barrera & Barrera Torres 168 (COL). ECUADOR. Without additional locality data, cultivated: 11 March 2005, Blanco 3012 (FLAS, SEL-spirit), 25 August 2009, Blanco 3231 (FLAS); 29 September 2003, Whitten et al. 2430 (FLAS, QCA). Morona-Santiago: Gualaquiza , Vertiente occidental de la Cordillera del Cóndor, arriba del Valle del Río Quimi , 1600 m, 11 December 2000, Freire 4314 (QCNE); Plan de Milagro , road Cuenca to Limón , ca. 15 km SW of Limón, 1900 m, 20 November 1989, Dodson et al. 17878 (MO, QCNE). Napo: 23 km E of El Chaco, Quito –Lago Agrio road, 1700 m, 7 November 1974, Gentry 12596 (MO, NY). Zamora-Chinchipe: Zamora–Cenepa, River Zamora , 1100 m, 26 July 1960, Dodson 182 (MO, SEL); Loyola, 1800 m, April 2001 (cultivated), Hirtz 7687 (SEL, mixed with Epidendrum sp. on separate sheet).

Conservation status:— Lockhartia tenuiflora appears to be uncommon but widely distributed along the eastern slope of the Andes in Ecuador and Colombia. Its geographic range includes several protected areas. Thus, this species is probably not threatened.

Etymology:— From the Latin tenuis (slim) and floris (flower), in reference to the slim appearance of the flowers in front view, due to the folding back of the lateral lobules of the labellum midlobe.

Comments:— Lockhartia tenuiflora is very similar to the Peruvian L. lepticaula , and it is very likely that both are sister species. Lockhartia lepticaula has a wider labellum midlobe and much larger, flabellate column wings.

De Retana (1991) published a photograph of Lockhartia tenuiflora (without assigning a species name). Dodson (2002) published another photograph of L. tenuiflora , erroneously identified as L. biserra ( Richard 1792: 112) Christenson & Garay (in Christenson 1996: 17).

It is interesting that Lockhartia tenuiflora has only been collected to the north of the Huancabamba Depression, while L. lepticaula has only been collected south of that geological feature (13 field collections seen for the latter species). This suggests that the Huancabamba Depression may have had a role in the divergence of these two putatively sister species. For a review of the potential role of the Huancabamba Depression as a phytogeographical barrier, see Weigend (2002, 2004).

Figures

FIGURE 4. Lockhartia tenuiflora M.A.Blanco. A. Plant habit, with flowers and fruits. B. Flower, front view. C. Flower, oblique view. D. Flower, lateral view. E. Same as previous, longitudinal section. F. Floral bract and base of pedicel. G. Dissected perianth parts (flattened, except lateral petal on right). Scale bar: 6.5 cm (for A), 1 cm (for B–G). Drawing by the author; A, based on Whitten et al. 2719 (FLAS); B–G, based on Blanco 3012 (FLAS).

FIGURE 5. Flowers of three Lockhartia species described in this paper; live plants used to prepare vouchers (cited in parentheses). A. Lockhartia endresiana (Blanco 4152, USJ). B–C. Lockhartia rugosifolia (Whitten 2432, FLAS, QCA); flowers in frontal and lateral views, respectively. D–F. Lockhartia tenuiflora (Blanco 3012, FLAS, SEL-spirit); flowers in frontal and lateral views, and inflorescence, respectively. Photos B and C by Mark W. Whitten; all other photos by the author.