Bulbophyllum macranthum collected in Thailand by K. Senghas in August 1978 (Photo: K. Senghas, Swiss Orchid Foundation at the Herbarium Jany Renz)
Bulbophyllum macranthum Lindl.
Least Concern (LC) according to IUCN Red List criteria. Listed on CITES Appendix II.
Lowland to montane forests.
About this species
During the warmer months, Bulbophyllum macranthum bears large, solitary flowers with an exotic, sweet perfume. The bright flowers are somewhat variable in colour and are unusual in that they are held upside-down in comparison to the majority of orchids. Instead of being resupinate (twisted so that the lip is borne upside-down), the lip is held at the top of the flower (non-resupinate).
Bulbophyllum macranthum belongs to the Sestochilos section of Bulbophyllum, the largest orchid genus in the world. Section Sestochilos contains about 23 species, most of which have one-flowered inflorescences and rather showy flowers with relatively large petals; species in this section often have thick, long-creeping rhizomes.
Bulbophyllum cochinchinense, Bulbophyllum purpureum, Carparomorchis macrantha, Phyllorchis macrantha, Sarcopodium macranthum, Sarcopodium purpureum
Geography and distribution
Bulbophyllum macranthum is native to Assam (India), Burma (Myanmar), Thailand, Cambodia, Vietnam, Nicobar Islands, Malaysia, Singapore, Sumatra, Java, Borneo, Philippines, Sulawesi, Moluccas, New Guinea and Solomon Islands. It is common in parts of this range, for example on the Nicobar Islands, but rare in others.
In some areas it can be confused with similar-looking species (B. praetervisum in Borneo, which differs in having a pair of downward-pointing teeth on the column, and B. grandifolium in New Guinea, which differs in having a triangular, rather than quadrangular, basal part of the lip).
Bulbophyllum macranthum grows in a very wide range of habitats, and has been collected in primary and secondary, evergreen, semi-deciduous and deciduous, broadleaf and coniferous, lowland to montane forests.
A robust, creeping, epiphytic (growing on other plants) orchid, with a rhizome 4–5 mm thick, which is covered with sheaths that break down leaving persistent fibres about 2 cm long. The pseudobulbs are about 3 cm tall and each bears a single 10–25 cm long, thick leathery leaf. The flowers are solitary, sometimes over 4 cm in diameter, and have fleshy, shiny sepals and petals. The dorsal sepals and petals are whitish with dense purple spotting and the lateral sepals are ochre-yellow, spotted with purple.
The British botanist Henry N. Ridley (1855-1956) described the flowers as smelling of cloves, while some have said they smell faintly of camphor.
Bulbophyllum macranthum is pollinated by fruit flies (Bactrocera species).
Threats and conservation
Many epiphytes have undergone a dramatic population decline, mainly because of habitat loss and timber extraction activities, which have driven many species close to extinction. Forests in parts of the region where Bulbophyllum macranthum occurs have been heavily logged, degraded and fragmented.
Bulbophyllum macranthum is a very attractive orchid, popular with hobbyists, and hence populations may suffer as a result of collection of individuals from the wild for the horticultural trade. The continued collection of Bulbophyllum macranthum in logged and secondary forests suggests that it is able to regenerate and persist in disturbed and secondary vegetation.
The species is currently listed on Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), meaning that international trade in it is controlled through permits.
Conservation assessments carried out by Kew
Bulbophyllum macranthum is being monitored as part of the 'Sampled Red List Index' project, which aims to produce conservation assessments for a representative sample of the world’s plant species. This information will then be used to monitor trends in extinction risk and help focus conservation efforts where they are needed most.
Bulbophyllum macranthum is cultivated as an ornamental by orchid enthusiasts.
This species at Kew
Bulbophyllum macranthum is grown in the behind-the-scenes Tropical Nursery at Kew and can sometimes be seen on display in the Princess of Wales Conservatory.
Dried and alcohol-preserved specimens of Bulbophyllum macranthum are held in Kew’s Herbarium, where they are available to researchers from around the world by appointment. The details of some of these can be seen online in the Herbarium Catalogue.
Clarke, A.R. et al. (2002). Evidence of orchid visitation by Bactrocera species (Diptera: Tephritidae) in Papua New Guinea. J. Trop. Ecol.18: 441-448.
Image: Swiss Orchid Foundation at the Herbarium Jany Renz (Please note that the usage of this image and information is subject to their disclaimer). Disclaimer available online.
Gutpa, S. et al. (2004). Orchid diversity of Great Nicobar Biosphere Reserve. Curr. Sci. 86: 1372-1376.
Keng, H. et al. (1998). The Concise Flora of Singapore: Monocotyledons. Singapore University Press.
Romand-Monnier, F. (2009). Bulbophyllum macranthum. Assessment using IUCN Categories and Criteria 3.1 (IUCN 2001). Royal Botanic Gardens, Kew.
Kew Science Editor: Patricia Malcolm
Kew contributors: André Schuiteman
Copyediting: Emma Tredwell
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