18 PHAL.KN0P3IS. 



termed the equatorial zone. We have already described in some detail, 

 under Dendrobium, the climatic phenomena of this zone, the most 

 salient characteristics of which may be conveniently repeated here, 

 since, under similar conditions, most of the species of Vanda, Aerides, 

 and other members of the sub-tribe Sarcanthe.t; live, notably those 

 species that are in high estimation amongst cultivators of orchids. 



The temperature of the equatorial zone is remarkable for its uniformity 

 throughout the year, the extreme range of the thermometer from the 

 lowest to the highest, at Batavia for example, rarely if ever exceeding 

 lo° C. (27° F.), while at other stations it is considerably less. The 

 highest day temperature is usually 33° — 35° C. (90° — 95° F.), while 

 it seldom falls below 21^-2t° C. (70°— 75° F.) at night, the coolest 

 hours being just before sun-rise. The annual rainfall is modified by 

 local circumstances ; in the Malay Archipelago and the southern 

 Philippines it ranges from 80 to 90 inches ; in these islands the 

 atmosphere is nearly always saturated with moisture, and, owing to 

 the great weight of vapour which its high temperature enables it to 

 hold in suspension, a very slight fall in the thermometer is accompanied 

 by the condensation of a large absolute quantity of atmospheric vapour, 

 so that copious dews and heavy showers of rain are produced at 

 comparatively high temperatures and low altitudes.* In Moulmein 

 the annual rainfall is much greater than in the Malay Archipelago, 

 and is distributed over ten months of the year, the remaining two 

 months, from about the middle of January to the middle of March, 

 being rainless ; in the Andaman Islands, which are still nearer the 

 equator, the dry season rarely exceeds four or five weeks ; in Cochin 

 China the climatic phenomena approach those of the Malay Archipelago, 

 except that there is a decidedly dry season of about two months' 

 duration. Within the equatorial zone the sea and land breezes are 

 among the most prevalent and constant of the aerial currents, and 

 within their influence nearly all the finest species of Phalaenopsis live. 

 The northern Philippines, Moulaiein, and southern Burmah being 

 within the sphere of the monsoons, the atmospheric disturbances in 

 those countries are more violent at certain seasons of the year. 



Cultural iVofp.— Tlie introiluction of specie.-^ of Phalaguopsis from the 

 neighbourhooil of the einmtor to the iiigli latitude of Great Britain, 

 to be cukivated in artiticiidlj heated glass houses, has been one of the 



* Wallace's Tropical Xature, p. 16. 



