— 120 — 



The pollination and fertilization in this genus are not very clear, though 

 the apparatus is apparently rather simple. But my observations are scant. 

 In Z. spectabile (PI. xvi, f. 4, 5) the long anther on the back wall of the flower is 

 bent forward in the flower mouth in such a way that the anther top touches 

 the patent lip at its base while the long hornlike elastic arcuate appendix 

 is extending before it, and its top from which the downbent stigma just 

 emerges occupies the center of the mouth, at a little distance above the lip. 



Bees visiting the flowers must enforce their entrance between anther 

 and lip, doing which they are all over covered with pollen of which they 

 find a large store in the tube under the anther. 



In retiring and leaving the flower it seems almost inevitable for them 

 to rub some of it against the stigma. To the contrary, in some species at 

 least (Z. Ottensii), the tip of the appendix is a little longer than the emerging 

 stigma and it seems as if the intruding bee must shut the stigma mouth 

 by pressing the appendix against it. So it seems as if the flower is 

 constructed for auto pollination. But this is only a supposition for I did 

 not observe the process actually. 



Owing to the extremely rainous westmonsun of 1917 — 18, insectvisiting 

 was scarce and 1 could only state that Z. aromaticum which opens its 

 flowers sometime before noon was regularly visited by swarms of Apis 

 indica and stray individuals of Anthophora zonata. Once 1 caught a specimen 

 of the latter species, where the hairy ventral side and legs where covered 

 with Zingiber-poUen, whille head and back where quite without. It is 

 difficult to realize how it can contribute to the pollination in this way. 



in this species a large proportion of the fruits ripen, though not so 

 many as in Z. ainaricans, where practically all flowers set fruit, as well of 

 our garden stocks as in spikes collected of wildgrowing specimens. 



In the latter species where the flowers open at 1.30 post m. 1 never 

 noticed beevisiting but I suppose that it took place in the same manner 

 on sunny hours, which, as is said, were rare, especially in the afternoon. 

 How the many thousands of flowers could have been fertilized is a mystery 

 to me. 



In the jungle garden Z. macradenia and Z. gramineum always fruit 

 abundantly, Z. leptostachyum (from Borneo) never does. 



In Z. Zerumbet of which 1 observed'several stocks of the most diverse 

 origin, with its large showy white flowers which expand from early morning 

 till night, no fertilization ever occurs and when anthesis is past the scape 

 decays immediately and the spike is bent down. Now Z. Zerumbet is in 

 Java a cultivated species since prehistorical times, while the two first named 

 species are found in Java spontaneous or escapes, one in the teak forests, 

 the other in waste grounds at Batavia. Both arc really indigenous, while 

 Z. Zerumbet is not. This may account for the difference in fruiting capacity, 



