89 



frustrated by the fact that it was impossible to make the pollen 

 stick on the stigmata; it was easy enough to bring it there 

 and keep it there for some time but it never penetrated; if 

 these flowers were later on put into alcohol the pollen loosened 

 again; in but one case (see fig. 19 PL V) it remained long 

 enough to bring the flower, previous to embedding, into 

 terpentine , but once there this flower lost its pollen also , 

 thus showing plainly that no penetration had occurred; it is 

 but fair to state however that these pollinations were only 

 tried in one season (1900) and that the large distance at which 

 the Ropalocnemis grows from my present residence did not 

 allow to leave the pollen more than 24 hrs. on the stigma. 

 I had to wait for 8 days at the habitat of Rhopalocnemis 

 before I found flowers in suitable conditions and when I finally 

 got them my time was up so that I had to abandon further 

 efforts. My friend K. A. U. Bosscha subsequently fertilised several 

 inflorescences for me , but in those cases also the pollen did not 

 stick. Apparently very favorable conditions are necessary to 

 make the pollen stick; it is not to be expected that pollen 

 which did not even stick after 24 hrs. would ever germinate. 

 Rhopalocnemis being thus able to form an endosperm nucleus 

 without fertilisation, how is it about the subsequent stages? 



As I indicated already the styles drop soon after formation 

 of the endospermnucleus. Subsequent stages, including seeds are 

 extremely rare. During two years it has been impossible though 

 hundreds of inflorescences were collected after the shedding of 

 the flowers, to obtain a single ripe seed. This does not api^ly 

 exclusively to the western part of the island , but also in Tegal 

 where after a kind communication of Dr. Raciborski the plant 

 is very common, this hawk-eyed botanist has been unable to 

 detect ripe seeds. 



Last year Mr. Bosscha sent me among a large number of 

 inflorescences one loJdch had ripe seeds, it is the only one which 

 has, as yet, been seen by me. 



Intermediate stages between the stadium of the endosperm- 

 nucleus and that of the ripe seed are extremely rare also, all 



Ann. Jard. Buitenz. 2e Ser. Vol. II. 7 



