Dixon — On the Vegetative Organs of Vanda teres. 443 



of the next leaf which encloses it, we find that its cylindrical base is 

 prolonged into a tubular petiole, which is attached to the stem by a 

 complete annular insertion at the node. At one point where the 

 cylindrical lamina passes over into the tubular petiole, there is a 

 minute passage leading from the exterior into a high dome-shaped 

 chamber, which completely includes the younger leaves. The passage 

 opens at a level considerably below that of the top of the petiole of 

 the outer leaf, which encloses the leaf under consideration. This will 

 be seen by reference to figure 1. As is shown in this figure, there are 

 usually two leaves included in this way by the dome-shaped space 

 formed by the petiole of the youngest visible leaf. The older of these 

 leaves is a short thick cylinder, with a cavity in the base, the chamber 

 formed by the petiole. From this chamber there is a passage leading 

 into the outer chamber, formed by the leaf which arches over this 

 leaf. This passage is diametrically opposite the passage of the outer 

 leaf. This inner chamber shuts in the rounded apex and the youngest 

 leaf. The latter is often seen in longitudinal sections, either as 

 a small prominence placed laterally to the rounded apex, or as a 

 collar (higher at one side) surrounding it. The higher side is imme- 

 diately under the passage of the second leaf. The parts of the young 

 leaves which are covered by the petioles of outer leaves are furnished 

 with glandular haii's, which disappear later on. These hairs are 

 particularly numerous in the passages leading into the chambers 

 formed by the petioles, and on the parts round these passages. 



The lamina of the developing leaf, which has arisen as a minute 

 protuberance at the side of the apex, and subsequently enlarged so as 

 to form a collar, higher at one side than at the other, evidently assumes 

 its axial position in order to emerge more easily through the passage 

 of the leaf which covers it over. In thus emerging it shoves the 

 lamina of the covering leaf from an axial position, and is, of course, 

 similarly displaced by the succeeding leaf. 



Transverse sections (PL xiv., fig. 22), through the base of the 

 leaves enclosing the apex show how the successive leaves are enclosed 

 by the petioles of their predecessors. 



The axillary buds formed near the apex are at first small swellings, 

 situated exactly in the axils of the leaves (PI. xii., fig. 6), and finally 

 their axis comes to lie almost in a horizontal direction (figs. 5 and 7). 

 During this displacement they develop several leaves, which resemble 

 those of the apex, except that their lamina is not so large. 



The same peculiar habit of piercing through the base of the sub- 

 tending petiole by the lateral branches is exhibited by many species of 



