Lockhartia rugosifolia M.A.Blanco, 2014

Blanco, Mario A., 2014, Four new species of Lockhartia (Orchidaceae, Oncidiinae), Phytotaxa 162 (3), pp. 134-146 : 139-142

Lockhartia rugosifolia M.A.Blanco , sp. nov. ( Figs. 3 , 5B,C )

Distinguished by its long, pendulous stems, rugulose leaves, and campanulate, yellow flowers with an oblong callus. Differs from Lockhartia parthenocomos ( Reichenbach 1852a: 639) Reichenbach (1852b: 767) by its rugulose leaves, inflorescence rachis completely concealed by bracts, smaller, yellow flowers (6−11 mm across), retuse labellum, and rectangular callus (vs. smooth leaves, inflorescence rachis not concealed by bracts, larger, white to cream flowers (10−15 mm across), suborbicular, labellum apex widely round, and callus formed by a transverse ledge in L. parthenocomos ).

Type:— PERU. Amazonas: [prov. Bongará?], Utcubamba river floodplain forest near Jazan (below Shipasbamba) , 1400 m, 29 June 1962, Wurdack 1090 (holotype: AMES !; isotypes: NY !, USM !).

Stems completely pendulous, more or less flexible, 28−84 cm long when reproductive, with 38−72 leaves; shoots (stem and leaves) 13−25 mm wide. Leaves marcescent, unifacial, laterally flattened, narrowly triangular in side view, with straight to slightly convex or concave abaxial (outer) margins, acute, rugulose–foveolate; exposed part of largest leaves 11−56 × 2−9 mm. Inflorescences both terminal and axillary from distal half of the stem, resembling grass spikelets, up to 11 per stem (sequentially produced?), with 1−4 flowers produced more or less sequentially; the rachis completely obscured by the bracts; exserted portion (i.e., part not hidden by the subtending leaf sheath) 1−2 cm long, internodes 1−2 mm long; inflorescence bracts amplexicaul, conduplicate, narrowly triangular to ovate, acute, scarious, 5−11 × 1−4 mm; pedicel and ovary 5−7 mm long, hidden by the floral bract. Flowers pendulous to resupinate, campanulate, 6−11 mm across, dark yellow with several pale brownish-orange horizontal bars across the center of the labellum (under the trichome pad). Sepals ovate, slightly concave, acute, 5−6 × 3−4 mm. Petals widely elliptic, flat, apically rounded, 6 × 5 mm. Labellum suborbicular, shallowly 3-lobate, 7−8 mm long, 10−11 mm wide when flattened; side lobes wider than long, transversely elliptic, slightly concave, 3 × 6−7 mm; midlobe wider than long, 2-lobulate, retuse, slightly reflexed, 2−3 × 5−6 mm; callus oblong, smooth, puberulous, not markedly thickened, occupying the central portion of the labellum, 4 × 2.5 mm. Column narrowly winged, subrhombic to spathulate, 3 × 2 mm, the wings obliquely oval and decurrent, wider distally, 0.5 × 1.5 mm; anther cap galeate, 1 × 1 mm; pollinarium 1 mm long. Fruit (undehisced) obovoid, 12−15 × 7 mm.

Phenology:— Field collections indicate that Lockhartia rugosifolia flowers at least in the months of January, May, June, August, and October. Flowers may actually be produced continuously or sporadically throughout the year.

Distribution:— Presently known from the Peruvian department of Amazonas, in the provinces of Bongará, Chachapoyas, and Rodríguez de Mendoza, in the Utcubamba River basin, from 1200 to 1600 m (but see below), on the eastern (Amazonian) side of the Andes. Apparently also present in the southeastern Ecuadorian province of Zamora-Chinchipe, on the basis of Hirtz et al. 7329 (SEL, from a cultivated plant reportedly collected in Zumba) and D’Alessandro 753 (RPSC, not found, listed as L. parthenocomos in Dodson & Bennett 1989 and in the Tropicos database (http://www.tropicos.org/Specimen/642345, last consulted on 28 January 2013); see commentary regarding confusion with the latter species).

I have also not been able to locate the specimen D. & A. Bennett 3409, cited by Dodson & Bennett (1989, as L. parthenocomos ), reportedly collected in Chachapoyas ( PERU, Amazonas) at 2800 m. This specimen most likely represents L. rugosifolia , and if so, it would significantly increase the elevational range reported above for this species.

Additional specimens examined: — ECUADOR. Without additional locality data, cultivated: 3 May 2004, Blanco 2568 (FLAS), 3 May 2004, Blanco 2569 (FLAS), 3 May 2004, Blanco 2570 (FLAS); 25 January 2000, Whitten et al. 1645 (FLAS); 29 September 2003, Whitten et al. 2432 (FLAS, QCA). Zamora-Chinchipe: Zumba, March 2000 (cultivated), Hirtz et al. 7329 (SEL). PERU. Without additional locality data: anonymous s.n. (Kspirit no. 28138.000); Mathews s.n. (BM no. 534522). Amazonas: Bongara, vicinity of Campomiento Ingenio 1−3 km up road to Pomacocha from Puente Ingenio, 1300 m, 27 January and 5 May 1974, Hutchinson & Wright 3837 (AMES, UC), Campomiento Ingenio on Río Utcubamba, 300 km E of Olmos, 1250 m, 10 October 1964, Hutchinson & Wright 6849 (UC 2 sheets); Chachapoyas, Jazán (Ingenio–Chachapoyas), ribera derecha del Utcubamba, 1200 m, 28 May 1963, López et al. 4275 (AMES, HUT); [Rodríguez de Mendoza], Mendoza, 1600 m, 8 August 1963, Woytkowski 8172 (GH, MO, SEL).

Conservation status:— Lockhartia rugosifolia is apparently a rare species, restricted to undisturbed forest in the Utcubamba River basin and possibly southeastern Ecuador. It is probably best to consider it Vulnerable.

Etymology:— From the Latin rugosus (rugose, wrinkled), and folium (leaf), in reference to the rugulose leaves, an almost unique condition in the genus.

Comments:— Lockhartia rugosifolia is remarkable for its long, pendulous stems, and holds the record for the largest recorded stem length in the genus (84 cm); L. longifolia ( Lindley 1846: 13) Schlechter (1919: 99) , also with pendulous stems, has a maximum recorded stem length of 80 cm, only slightly shorter. The rugulose leaf texture, and the spikelet-like condensed inflorescences with strongly conduplicate, laterally flattened, distichous bracts, are also diagnostic features of L. rugosifolia .

The leaves of L. parthenoglossa Reichenbach (1865: 300) (not L. parthenocomos ) also have a rugulose texture, but much less pronounced and visible only under magnification. Lockhartia parthenoglossa occurs only from Belize to Colombia and not in Peru.

Lockhartia rugosifolia has been confused with both L. longifolia and L. parthenocomos , both of which it resembles superficially, especially in its pendulous stems and yellow flowers. It differs from L. longifolia in its straight, verruculose leaves, campanulate flowers, concave labellum and a low, oblong callus (vs. generally sigmoid, smooth leaves, widely open flowers, convex labellum and a crateriform callus in L. longifolia ). The floral morphology is more similar to that of L. parthenocomos , although that species has smooth leaves, much larger, white to cream flowers, a transverse, ledge-like callus, and occurs only in the Venezuelan Coastal Range.

Escobar (1998: Figure 1060) published a photograph of Lockhartia rugosifolia (as Lockhartia sp. ) in volume 6 of Native Colombian Orchids, labeled as Escobar Nº 8170 (voucher not found). The figure legend says “without exact locality, Antioquia? [...] Grower: Rodrigo Escobar”. The northernmost field collection of L. rugosifolia is from Zumba in southeastern Ecuador, more than 600 km south of the Colombian border. Thus, the plant illustrated by Escobar was probably not collected in Colombia.

Dodson & Bennett (1989) and Dodson (2002) also published illustrations of Lockhartia rugosifolia , erroneously identified as L. parthenocomos . Some authors (e.g., Brako & Zarucchi 1993, Jørgensen & León-Yánez 1999, Zelenko & Bermúdez 2009) have propagated this error, listing L. parthenocomos in species checklists for Ecuador and Peru. Zelenko & Bermúdez (2009) published a photo of L. rugosifolia (as Lockhartia sp. ), and misidentified a photo of L. longifolia (as L. parthenocomos ).

Lockhartia rugosifolia has been in cultivation for several years, almost always under the name L. parthenocomos . Unlike most other species of Lockhartia , L. rugosifolia appears to be difficult to keep alive in cultivation for long periods, at least in places where the nighttime summer temperatures cannot be maintained below 25ºC (M.A. Blanco, personal observation).

Figures

FIGURE 3. Lockhartia rugosifolia M.A.Blanco. A. Plant habit. B. Distal part of a shoot with six inflorescences, one with a flower. C. Detail of leaf texture. D. Flower, front view. E. Flower, lateral view. F. Same as previous, with sepals and lateral petals removed. G. Floral bract, flattened; basal right portion damaged. H. Dissected perianth parts (flattened), with column in center (ventral view). Scale bar: 10 cm (for A), 4 cm (for B), 8 mm (for C), 1 cm (for D–H). Drawing by the author, based on Wurdack 1090 (AMES).

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.