Notes on the Fertilisation of a Few 

 Orchids in Sarawak. 



By C. J. Brooks and John Hewitt. 



In the tropical forests of Sarawak, orchids are relatively 

 very abundant and a great number of species are there found. 

 A fair proportion have large showy flowers or a conspicuous 

 inflorescence but the majority are small flowered and are not 

 conspicuous. As is well known the peculiar structure of the 

 typical orchid flower is a special adaptation to effect cross 

 fertilisation through the agency of insects but in reality 

 many orchid flowers are rarely visited by insects. The well 

 known orchid Phalaenopis grandiflora produces a spike of 

 large and conspicuous white flowers but though Sarawak is so 

 rich in insect life an insect visitor is never seen on the flowers: 

 and the spike remains in bloom for months until eventually 

 the flowers die without producing a single seed pod. If a 

 single flower be self-fertilised by human agency the whole 

 spike fades in a few days and a seed pod is formed. 



In the swampy parts of Sarawak Bromheadia palustris is 

 very common: it produces conspicuous white flowers at fairly 

 regular intervals of three or four weeks but though these have 

 been under continuous observation for a long time we have 

 never seen a large insect on the flower. Still it may perhaps 

 be visited occasionally as sometimes a seed pod is formed, 

 Vanda hookeriana has fine large flowers, the petals spotted 

 with a rich velvet lake and it is always to be found in flower. 

 These flowers if they are not fertilised may remain in good 

 condition for a week: at the end of that time, or in case they 

 lose tbeir pollinia or are fertilised on the day after the visit 

 of the insect, the petals become much bleached the colour 

 disappearing almost entirely. This orchid not infrequently 

 bears seed pods and I am told by the Malay gardeners that 



Jour. Sraits Branch R. A. Soc, No. 54. 1909- 



