Lockhartia compacta M.A.Blanco & R.Vásquez, 2014

Lockhartia compacta M.A.Blanco & R.Vásquez View in CoL , sp. nov. ( Fig. 1 View FIGURE 1 )

Similar to Lockhartia micrantha Reichenbach (1852b: 768) , but differs from that species in the more compact plants and the structure of the callus, which is suboblong and ligulate (vs. bifid in L. micrantha ).

Type:— BOLIVIA. Santa Cruz: prov. Florida, El Sillar, 1350 m, Parque Nacional Amboró , epífita en bosque tucumanoboliviano, 3 Julio 1995, Vásquez 2522 (holotype: LPB!) .

Stems straight, descendent, 5−10 cm long when reproductive, more or less rigid, completely covered by the leaves, each one with 20−24 leaves. Leaves marcescent, unifacial, laterally flattened, triangular in side view, with straight to slightly incurving margins, acute to obtuse apically, exposed part of largest leaves 3−16 × 1−8 mm wide. Inflorescences axillary (and probably also terminal) from the distal half of the stem, with 1−2 flowers produced sequentially; exserted portion 5−9 mm long, internodes 1−2 mm long; inflorescence bracts amplexicaul, infundibuliform, cordate-acute when flattened, 2.5−3 × 2−3 mm; pedicel and ovary 4−5 mm long. Flowers resupinate, widely open, 7−8 mm tall, yellow with scant brown markings at the base of the lateral lobes of labellum and dark brown at base of column; labellar callus pale brown. Sepals elliptic to obovate, slightly concave, apex apiculate and navicular, 4−4.5 × 2.5 mm. Petals elliptic, flat, apically rounded, 4.5 × 3 mm. Labellum 3-lobate; the lateral lobes oblong, gradually diminishing in width, erect, 3 × 1 mm, apically rounded; midlobe distally 4- lobulate, apically emarginate, 6 mm long, 2.5−3 mm wide at the base, 4.5 mm at the widest part near the apex, with a slightly concave disk 1 × 1.5 mm at the base (with glandular hairs); prolonged into a simple oblong callus, 2.5 × 1 mm. Column triangular, subequilateral, 1.5−2.5 mm wide at base, 2 mm tall without anther cap, stigmatic cavity ovate, 7−8 mm long, rostellum remnant digitiform, protruding into apical part of stigma; anther cap not seen; pollinarium 0.5 mm tall, viscidium triangular, stipe bifid, with two pollinia; pollinia ellipsoid, 0.2 mm long. Fruit not seen.

Phenology:— Flowering at least in July and September.

Distribution:— Endemic to Florida province, department of Santa Cruz, in the eastern side of the eastern Andean Cordillera in Bolivia, from 1000 to 1300 m. This represents the southern limit of distribution of the genus Lockhartia in the Andes ( L. lunifera [ Lindley 1839: misc. 91–92] Reichenbach [1852b: 767] and L. goyazensis Reichenbach [1852b: 768] occur farther south in Brazil).

Additional specimens examined:— BOLIVIA. Santa Cruz: Prov. Florida, Refugio Los Volcanes, Río Elvira , 1000 m, Vásquez et al. 4259 (Herb. R. Vásquez) ; Prov. Florida, Refugio Los Volcanes, Río Elvira , 1000 m, Vásquez et al. 4281 (Herb. R. Vásquez) .

Conservation status:— Lockhartia compacta is known from very few collections and appears to be rare and restricted to a small area of the Bolivian-Tucuman Forest biome. Collectors likely overlook plants of L. compacta because of their small flowers.

Etymology:— The name comes from the Latin compactus, in reference to the very compact plants and their small flowers.

Comments:— Lockhartia compacta is very similar to L. micrantha , but differs from that species in the ligulate callus and the more distal position of the lateral lobules of the labellum midlobe. Lockhartia micrantha has a bifid callus. Plants of L. compacta have more compact shoots than those of L. micrantha (2.4−4 vs. 1.5−3.5 leaves per linear cm of stem, respectively). The ranges of both species are separated by thousands of kilometers ( L. micrantha occurs from Nicaragua to Colombia and Venezuela).

Furthermore, Lockhartia compacta superficially resembles L. goyazensis , which occurs in Bolivia (e.g., misidentified as L. ludibunda Reichenbach (1857: 159) in Dodson & Vásquez 1989). In Bolivia, however, L. goyazensis occurs at lower elevations (150−400 m, although it has been collected as high as 900 m in Brazil) in the Humid Evergreen Forest and Humid Amazonian Forest biomes (sensu Vásquez & Ibisch 2000). Lockhartia goyazensis has slightly larger flowers with longer and narrower lateral lobes of the labellum and a massive, tuberculate callus that covers a large portion of the middle lobe (ca. 50% of its surface, vs. ca. 20% in L. compacta , which has a smooth callus).