Renanthera

Vandeae subtribe Aeridinae. Some authors maintain Renantherella as a separate genus based on its proportionately longer column.

Vining monopodial epiphytes. Stems elongate, leafy, rooting at the nodes. Leaves alternate, distichous, usually bilobed at the apex, leathery. Inflorescences axillary racemes or panicles, suberect to horizontal, when paniculate the branches oriented in one plane. Flowers showy, brilliantly-colored, yellow with orange-red spots to deep vermillion. Sepals and petals free, spreading, the lateral sepals usually much larger and clawed. Lip three-lobed, with paired calli at the throat, with a short spur. Column short to elongate (Renantherella); pollinia 4, in two unequal pairs, with a stipe and viscidium.

From the Latin renes, meaning kidney, and anthera, meaning anther, in allusion to the kidney-shaped pollinia.

A genus of 17 species ranging from Nepal to the Philippines, New Guinea, and the Solomon Islands.

1 Flowers with the lip uppermost, not resupinate. R. histrionica 1' Flowers with the lip lowermost, resupinate. 2 2(1') Leaves linear, to 0.8 in. (2 cm) wide. 3 2' Leaves strap-shaped to oblong, more than 0.8 in. (2 cm) wide. 6 3(2) Flowers yellow with orange-red spots. 4 3' Flowers orange-red with darker red spots. 5 4(3) Petals linear, to 0.1 in. (0.3 cm) wide. R. matutina 4' Petals lanceolate, to 0.2 in. (0.4 cm) wide. R. monachica 5(3') Sepals and petals obtuse-rounded; the lip with a pair of calli at the base of the midlobe. R. auyongii 5' Sepals and petals acute-acuminate; the lip without callus. R. bella 6(2') Flowers yellow, with at most a few spots. 7 6' Flowers orange to red, heavily spotted with red when yellowish-orange. 8 7(6) Dorsal sepal to 0.7 in. (1.8 cm) long; midlobe of lip to 0.1 in. (0.2 cm) wide. R. citrina 7' Dorsal sepal to 0.5 in. (1.3 cm) long; midlobe of lip to 0.2 in. (0.4 cm) wide. R. pulchella 8(6') Dorsal sepal about half the length of the lateral sepals. 9 8' Dorsal sepal about the same length as the lateral sepals. 10 9(8) Lateral sepals to 0.4 in. (1 cm) wide; lateral lobes of the lip broadly ovate-triangular. R. coccinea 9' Lateral sepals to 0.8 in. (2 cm) wide; lateral lobes of the lip narrowly lanceolate-triangular. R. imschootiana 10(8') Lateral sepals to 1.6 in. (4 cm) long. R. storiei 10' Lateral sepals less than 1 in. (2.5 cm) long. 11 11(10') Lateral sepals less than 0.12 in. (3 mm) long. 12 11' Lateral sepals more than 0.2 in. (5 mm) long. 13 12(11) Leaves to 1.9 in. (5 cm) wide, mucronulate between the apical lobes. R. edelfeldtii 12' Leaves to 1 in. (2.5 cm) wide, without an apical mucronule. R. elongata 13(11') Lateral lobes of the lip dark red; sepals of equal length. R. isosepala 13' Lateral lobes of the lip white; lateral sepals somewhat longer than the dorsal sepal. R. philippinensis

Averyanov, L. V. 1997. Renanthera citrina. Orchids 66(12):1284-1290; Christenson, E. A. 1986. Renanthera auyongii, a new species from Sarawak. Orchid Review 94(1114):264-265 (reprinted in Orchid Digest 50(5):169-170. 1986; Holttum, R. E. 1986. On Aerides elongata Bl. (Orchidaceae). Kew Bull. 41(2):347-348; Kamemoto, H. and K. Shindo 1962 1962. Genome relationships in interspecific and intergeneric hybrids of Renanthera. Amer. J. Bot. 49:737-748; Mahyar, V. W. 1988. Observations on some species of the orchid genus Renanthera Loureiro. Reinwardtia 10(4):399-418; Quisumbing, E. 1950. The genus Renanthera of the Philippines. Philip. Orchid Rev. 3:3-11; Rice, R. 2000. Renanthera, the Scarlet Ladies of vandaceous orchids. Orchids Austral. 12(6):16-20; Senni, S. and P. G. Latha 1992. Foliar regeneration of the endangered Red Vanda, Renanthera imschootiana Rolfe (Orchidaceae). Plant Cell, Tissue and Organ Cult. 29:167-172; Voelker, E. J. 1970. Culture of Renanthera monachica. Amer. Orchid Soc. Bull. 39:881-884.