COLOR 181 



tain Geddeh, 4500-6500 feet, in Java, with 

 a very moist air have but little anthocyan 

 while on Pangerango, at a height of 10,000 

 feet, with a dry atmosphere the presence of red 

 coloring matter was ver\^ marked. The pow- 

 er of absorbing the photochemical rays pos- 

 seSvSed by moist air would preclude the need 

 of a protective coloring in the first instance. 

 The writer has noticed that the young and 

 pendant leaves of the mango (Mangifera) are 

 but slightly colored in the lowland habitats 

 of the tree in Jamaica but on the mountain 

 sides, near 1000 feet, the young bunches show 

 a perfect blaze of color especially in dry reg- 

 ions. Here, as in the highly colored young 

 leaves of the maple, oak, grape, sumac, alder 

 and others, the red coloring matter doubtless 

 serves as a protection against the penetrating 

 rays of the sun. At the same time it is to be 

 borne in mind that the low temperatures of 

 the elevations mentioned, or of the spring 

 season ma\^ be the direct cause of the forma- 

 tion of the anthocyan. 



The most satisfactory proofs of the forma- 

 tion of anthocyan as a screen are given by the 

 exposure to daylight of plants growing in 

 darkness. Under such circumstances the 

 pearh" white rhizomes of Dentaria hulbifera 

 become violet. Plants of Philotria canaden- 

 sis (Elodea) and Utricularia vulgaris grown 



