Chap. IV] TROPICAL DISTRICTS CONSTANTLY MOIST 327 



Wiesner' made a number of determinations of tlie amount of 

 ligiit in the orcliid quarter of the botanic garden at Buitenzorg. 

 The orchids arc cultivated there on stems of species of Plumiera, in 

 the shade of lofty trees of Evia acida, Bl. 



The brightness in the orchid quarter was on tlie average i/io-8 of 

 the full daylight, and the diffuse front light on the stems of the 

 Plumiera trees was on the average 1/60-1/65 of the total daylight 

 (I maximum = o-o25-0'023). When the sun shone, the intensity 



Fig. 169. Tillandsia usiieoides. Fragment of a shoot. Natural size. 



of the light from above rose to i/4v-i/7-7 of full daylight (I maxi- 

 mum = 0-3I9-O-I94). 



The following orchids were growing well : Agrostophyllum javani- 

 cum, Bl., Eria ornata, Lindl., Spathoglottis plicata, Bl., Thelasis 

 carinata, BL Others, on the contrarj', appeared to feel the want 

 of sufficiently intense light ; for instance, Thelasis elongata, Bl., 

 Dendrobium acuminatissimum, Lindl., Coelogj^ne Rochusseni, De 



Vriese. C. Lowii, Pont., C. macrophylla, 



Toi;o„, ...t r>- T J » • 1 TT 1 .^ Fig. 168. Tillandsia 



leijsm. et Bum., \ anda tricolor, Hook., On- ,„„eoides. Sprig. One- 



cidiuni ampliatum, Lindl. lifth natuinl size. 



' See p. 55. 





