Thursday, March 31, 2016

[Botany • 2016] Porpax verrucosa • A New Species (Orchidaceae) from the Cardamom Mountains in Cambodia

Porpax verrucosa Schuit.

A new species of Porpax (Orchidaceae - Epidendroideae - Podochileae) from the Cardamom Mountains in Cambodia is described and illustrated. It is similar to P. elwesii but differs in the much broader and longer, obovate petals that are covered with numerous, glassy, enlarged cells, giving a verrucose appearance.

Key Words: Cardamom Mountains, Mekong Region, taxonomy

Porpax verrucosa Schuit., sp. nov. 

Type: Cambodia, Koh Kong Province, Thma Bang Distr., foothills of Cardamom Mts, 23 Nov. 2013, also flowered in cultivation at Kew, 27 Nov. 2014, Kew cult. 2013-1679 (leg. A. Schuiteman, C. Ryan & M. Nut) (holotype K, spirit mat.; isotype Forestry Administration Herbarium, Phnom Penh, Cambodia).

RECOGNITION. Similar to Porpax elwesii (Fig. 3) in the non-reticulate veins of the sheath that covers the pseudobulb, glabrous flowers, and in the inflorescence arising from the apex of the mature, leafless pseudobulb. P. verrucosa differs in the broadly obovate petals about as long as the sepals (vs narrowly oblong petals much shorter than the sepals); petals and to a lesser extent the sepals adorned with very large, glassy, swollen cells, giving the appearance of warts (lacking in P. elwesii); sepals at apex shortly apiculate (vs sepals long-apiculate).

DISTRIBUTION. Only known from the type locality in Cambodia.

HABITAT AND ECOLOGY. Epiphyte on mossy, dead tree trunk in disturbed evergreen hill forest on a ridge crest. Elevation 430 m.
PHENOLOGY. Flowers in November.

ETYMOLOGY. From the Latin verrucosus, warty, referring to the large, swollen cells on the petals and sepals.

CONSERVATION ASSESSMENT. Porpax verrucosa is only known from about a score of specimens found in a single locality on a single tree trunk. Potentially suitable habitat is still widespread in the Cardamom Mountains and since the distribution of this easily overlooked species is unknown at present, its conservation status should be classified as Data Deficient (DD), following the IUCN Red Listing criteria (IUCN 2012).

NOTES. This is the first known species of Porpax that is endemic to Indochina. The centre of diversity of the genus lies more to the west, in Thailand, Burma and India.

André Schuiteman. 2016. Porpax verrucosa (Orchidaceae), A New Species from Cambodia. 
Kew Bulletin. 71:4. DOI:  10.1007/s12225-016-9615-z