Macradenia grandiflora A.K.Koch, Ilk.

Macradenia grandiflora A.K.Koch, Ilk. View in CoL -Borg. & F.Barros. sp. nov. ( Fig. 1 View FIGURE 1 )

Macradenia grandiflora is closely related to M. lutescens differing by the larger size of leaves, flowers, lip and column, by the cuspidate apex of sepals and petals, and by the number of lip calli.

Type:— BRAZIL. Minas Gerais, Mun. Timóteo, Macuco, Parque Estadual do Rio Doce 19º35’28”S, 42º34’07”W, 03 March 2004, G. S. França & F. Raggi 500 (holotype: BHCB!) GoogleMaps

Herb, epiphytic, caespitose, ca. 27 cm tall. Roots slender, flexuous, glabrous. Pseudobulbs terete-oblong, 4.5–5 cm long, slightly curved, monophyllous, subtended at the base by 2 triangular sheaths, 3–4 × 1–2 cm, apex acuminate to acute, scarious, brown spotted. Leaves linear-lanceolate, 22.5–23 × 3 cm, subcoriaceous, apex acuminate, base in a pseudopetiole, conduplicate. Inflorescence a lateral raceme, up to 4–12.5 cm long, 6–20-flowered with 1–2 triangular bracts, 5–8 × 2 mm, with a single branch (sometimes two) in the third bract of the peduncle, peduncle slender; floral bracts triangular, 3–5 × 1–2 mm. Flower probably brown (herbarium collection); dorsal sepal elliptic-lanceolate, 1.3– 1.9 × 0.3–0.4 cm, apex cuspidate; lateral sepals lanceolate, 1.3–1.5 × 0.3–0.4 cm, apex cuspidate; petals lanceolate, 1.3–1.4 × 0.2–0.3 cm, apex cuspidate; lip probably brown, sessile, 3-lobed, subcordiform when distended, 1.2–1.3 × 0.8–0.9 cm, margin entire; lateral lobes suborbiculate, 7 × 4 mm, with a flat intramarginal membranaceous ridge from the base up to 2/3 lateral lobe, apex rounded; midlobe linear-lanceolate, 6 × 1–2 mm, apex acuminate; disc with a central linear keel. Column fleshy, subterete, 0.6–1 cm long, slightly dilated at the apex, clinandrium irregularly lacerate, stigmatic cavity slit; pedicel + ovary 0.8–1.5 cm long. Pollinia 2, obovate, dorsal-ventrally compressed, stipe attenuate, expanded at the apex, 6 mm long, viscidium elliptic. Fruit not seen.

Distribution, habitat and conservation status:— Macradenia grandiflora is only known from the type-locality, the “Parque Estadual do Rio Doce”, in Minas Gerais, Brazil ( Fig. 2 View FIGURE 2 ), where it was found growing in Submontane Seasonal Semideciduous Forest. The species has been collected with flowers in March and April. According to the IUCN (2014), M. grandiflora should be rated as Data Deficient (DD) category.

The closest related species to M. grandiflora , M. lutescens , has a broad distribution in the Neotropics, ranging from southern United States to Brazilian Amazon ( Govaerts 2015). In Brazil, M. lutescens was recorded in Mato Grosso state only ( Barros et al. 2015), but the first author also examined herbarium collections from Amazonas, Pará and Roraima states (INPA, MG, SP and UFP).

Etymology: —The epithet refers to the size of flowers which are among the largest in the genus.

Aditional specimens examined (paratype):— Brazil: Locality unknown, cultivated at Orquidário Florália , Rio de Janeiro, 02 April 2003, leg. unknown ( UEC!) .