63 



Fig. 5. — Column of expanded flower. The pollinia are diver- 

 gent, and rest in the horizontal plane behind the rostellum and the 

 stigma ; the column-wings are wide and deep ; the anther-point 

 is yellow and woolly ; the rostellum and pollinia can be easily 

 removed. Lettering as in fig. 4. 



Plate VIII. b. 



Thelymitra luteocilium, Fitz. 



Showing the front of the column (magnified 6 times) at 

 various stages of development. 



Fig. 1. — The column of a very young bud, showing the posi- 

 tion and shape of the still closed pollen-cases, the anther-tip, the 

 stigma, rostellum, and pencillate appendages — s, stigma ; r, ros- 

 tellum ; p c, pollen-cases; ap, anther-point; lap, pencillate lateral 

 appendages. 



Fig. 2. — A slightly more advanced stage, showing the pollen- 

 cases beginning to dehisce. The friable pollen is seen between the 

 receding margins. Lettering as in fig. 1. 



Fig. 3. — A still more mature column. It has grown taller and 

 wider ; the anther has been carried up with its growth ; the 

 dehiscing margins have retracted greatly; the pollen has massed 

 itself over the rostellum and stigma ; some has fallen upon the 

 stigmatic surface. Lettering as in fig. 1. 



Fig. 4. — Column in which pollination has been completed. The 

 pollen-cases are empty, showing the inter-locular septem between 

 them. Pollen is seen on the surface of the stigma and massed up 

 in the cup-like depression at its base. Lettering as in fig, 1. 



Plate IX. a. 



Column of Thelymitra fuscolutca (magnified 3 times), showing 

 various stages in the iDrocess of pollination. 



Figs. 1 and 2 show the structure of the column before 

 dehiscence oi the anther. Note the wings of the column widely 

 expanded into a combed hood. In fig. 2 one side of this expansion 

 has been cut away, so as to show the attachment of the anther to 

 the column and the position of the pollen -cases relatively to the 

 stigma. They are well behind the stigma, and cannot be seen from 

 the front at this stage. Note also in this figure the obliquity of 

 stigma and the peculiar dorsal appendage (or middle lobe) of the 

 column — X, dorsal appendage of column ; a p, anther-point ; iv, 

 wings of column; r, rostellum; s, stigma; p c, pollen-case. 



Fig. 3. — A more advanced stage. The growth of the column 

 has brought the pollen-cases above the level of the stigma, oblique 

 dehiscence has already commenced exposing a small area of pollen 

 in each case. Lettering as in figs. 1 and 2. 



Fig. 4. — Front view of column at a slightly later stage. Pollen 

 has fallen on the rostellum and upper part of the stigma. The 

 anther has inclined further forward. Lettering as in figs. 1 and 2. 



Fig. 5. — Front view showing a column in which the rostellum 

 has fallen forward, so as to widen the space through which the 

 pollen escapes on to the stigma. Lettering as before. 



