SELF-FERTILIZATION TS TROPICAL ORCHIDS. 549 



Fig. 13. Is a front view of a fully-fertilized flower (of the purple variety), some- 

 what more enlarged in proportion than the other figures. 



14. Represents the same with the anther-cap removed ; the pollinia have 



become cheesy and swollen. 



15. Represents an "end on" view of the top of the column, showing the 



rostellum, and the spots (marked yellow) where the fluid from the 

 stigma makes its way into the anther. 



16. Shows the direction taken by the pollen-tubes from the swollen pollinia. 



Arundina speciosa. 



17. A young bud in which the pollinia are seen in situ, and the shape of the 



stigma is nearly perfect. 



18. Is a somewhat advanced bud in which the upper part of the stigma has 



disappeared, and the lower edges are approximated to the pollinia. 



19. Represents an Arundina in which the pollinia have rotated quite into the 



stigma, whose lower lips have embraced the anther-cap. 



20. Is a fully-fertilized flower (with the anther-caps removed), with the 



pollinia shown in situ and becoming a cheesy mass. The front of the 

 column has burst, a circumstance which often happens from the great 

 number of pollen-tubes emitted from the pollinia. 



21. Is a longitudinal section of a bud, showing the rostellum, which has 



grown far down the stigmatic canal. 



22. Is a figure of a very young bud in which, though the pollinia had 



scarcely begun to rotate, the stigma had become already much modified 

 and is in waiting for the rotation of the pollinia. 



23. Represents what I have termed in the text the more natural orchideal 



form of the rostellum, where it is a broad platform overhanging the 

 stigma. In this form Hie flower never becomes fertilized. 



Plate XVII. 



Eria, sp., near Eria javensis. 



Fig. 1. A side view of a flower ; enlarged. 



2. A front view of a flower ; enlarged. 



3. Thelabellum. 



4. The stigma, with three pollen-masses which have fallen forward on it ; 



and with the anther-cap shrivelled backwards. 



5. Represents the anther and rostellum as seen in the bud. 



Chrysoglossum, sp. 

 fi. Is the enlarged ovary, shoeing the shrivelled flower at the top, which 

 had remained as a bud throughout its existence. 



7. A young bud (much magnified), showing the position of pollinia wUh 



reference to the stigma. 



8. Labellum enlarged, and coloured according to nature. 



0. A longitudinal lateral section, showing the pollin.a which, havmg 

 become inundated with fluid in the stigma, have emitted their pollen- 

 tubes down into the ovary. 



