268 



When dehiscence occurs, the covering membranes retract 

 widely; the pollinia of the lower series are brought into con- 

 tact with the stigmatic fluid, and seepage begins to take 

 place, particularly into the two external masses. So rapidly 

 do these latter become affected, that they rarely change their 

 position and become quickly amalgamated with the viscid 

 contents of the stigma. The inner pair usually slip down at 

 the apices which are commonly to be seen protruding round 

 the inner margins of the stigmatic appendages. Members 

 of the upper series are subsequently liberated by retraction 

 of the interlocular septa. The pollinia soon become cheesy 

 under the influence of the stigmatic fluid and are then con- 

 verted into a glutinous mass. Innumerable pollen-tubes are 

 developed and may be traced as a mucoid cord down the 

 stigmatic canal to the ovary. 



Self-pollination therefore takes place in the bud, and 

 it is inevitable that every flower should become fertilized, 

 unless some untoward circumstance should interfere with the 

 descent of the anther. 



The only service conferred upon the plant by the expan- 

 sion of the flower would appear to be the rapid drying up of 

 the stigmatic contents and the effectual sealing of the stig- 

 matic-canal. After expansion, the remains of the four lower 

 masses are still to be traced as four rather dense elastic 

 caruncles adhering to the back of the stigma. 



2. P. Bernaysii, Rowl. This species bears a large and 

 handsome yellow flower. Structurally the column approaches 

 closely to that of P. grandifolius, but whereas the opening 

 into the stigmatic cavity of the latter is V-shaped, in P. 

 Bernaysii it is quadrilateral in form and very much smaller. 

 The chief difference, however, is to be found in the attach- 

 ment of the pollinia, which are approximately of the same 

 size in both series so long as they are uninfluenced by the 

 stigmatic fluid. A careful examination of the material avail- 

 able failed to disclose any evidence of attachment by 

 dichotomous caudicle, even at an early stage of bud develop- 

 ment. It was noted that at the apices of the masses, the 

 granular material occasionally assumed a loose linear form- 

 ation remotely resembling a caudicle, but in no instance did 

 there appear to be a dichotomous connection between the 

 individuals of a pair and between the corresponding pairs of 

 two series, such as was found to exist in P. grandifolius. 

 Dehiscence takes place very early in the bud, but pollinia are 

 often retained, longer than would be expected from the frail 

 nature of their attachment, some generally being found in 

 situ after expansion of the flower. They also retain their 



