Rennekt : The Phvllodes of Owpolis filifurmjs 405 



septa. I am not able to account for the difference in these septa 

 as observed by Briquet and myself, except to suggest that his 

 plants were grown under conditions which induced the sclerosis of 

 the elements of the septa and which he has not described. 



The most important additional fact concerning the structure of 

 these organs, however, is that all of the specimens in the herbarium 

 of the New York Botanical Garden, and of those cultivated by my- 

 self in the open, exhibit the pits or depressions mentioned above, 

 and this feature is to be seen even in the first leaf of the seedlings. 

 These pits seem to be the external openings of oil or resin glands 

 which are situated immediately below each septum. The pit is 

 partly closed by a chlorophylless outgrowth of the lower margin, 

 which can be distinguished by the unaided eye as a minute scale. 

 Goebel * describes similar outgrowths on the phyllodes of Crantzia 

 linearis, an umbellifer of the same habit as Oxypolis, and despite the 

 fact that they occur along one side of the leaf only, he holds the 

 opinion that they are vestigial leaf-divisions. This conclusion can 

 hardly be valid with respect to the pits and scales of Oxypolis. 

 These formations are absent from the basal septa as they would be 

 if vestigial leaf-divisions, but as a matter of fact the scales and pits 

 originate on a line ninety degrees from the plane of the stipules. 

 Furthermore the specialized structute of the formations in question 

 militates against their acceptance as vestiges. 



It was found that the floor of the pit is on a level with the 

 plane of the diaphragm. It is this floor and the flap which closes 

 the orifice only, whose structure indicates a specialization of func- 

 tion. With these exceptions the invagination is lined by a con- 

 tinuation of the normal epidermal cells of the phyllode, covered by 

 a cuticle continuous with that on the outside of the leaf. The floor 

 and flap have an epidermis of smaller cells the outer walls of which 

 are slightly convex, forming small papillae. No cuticle is present. 

 The small openings which occur in this epidermis measure about 

 19/y. in diameter and are formed by two cells broadly elliptical in 

 shape. Directly below these epidermal cells and making up the 

 greater part of the flap is a mass of irregularly shaped cells dove- 

 tailed compactly into each other. The epidermal cells as well as 

 the cells of this tissue contain a great amount of resin or oil. En- 



* Goebel, K. Organographie der Pflanzen, 494. 1901. 



