no 



RELATIONSHIPS OF SYMMETRY 



unlike in form ; the upper leaves indicated by Arabic numerals in 

 Fig. 63 are much smaller than the under ones, but they possess, like 

 them, axillary stipules. In Elatostemma sessile the upper leaves are 

 more reduced (see Fig. 64) ; there is no longer found here the differentia- 

 tion which results in the formation of an axillary stipule to the leaf, and 

 the upper leaf itself may be readily taken for an axillary stipule ; the 

 under leaves are on the other hand constructed as foliage-leaves, each 

 of which has an axillary stipule serving as a membranous protection to 

 the bud. Fig. 64 represents a cross-section of the bud ; the foliage- 

 leaves are indicated by Roman numerals, the small scale-leaves opposite 

 to them by letters ; leaf / is 

 not indicated, its axillary 

 stipule, j/ 1} is alone represented 

 in the figure. Opposite to 

 leaf / stands the scale-leaf 

 a which takes no share in 

 assimilation, and only serves 

 as a protective organ l . In 



FlG. 63. Pellionia Daveauana. Trans- 

 verse section of a l>ud. The larger leaf of 

 each leaf-pair is indicated with a Roman 

 numeral, the smaller with an Arabic numeral. 

 The axillary stipule of each leaf is indicated 

 by j/ with its corresponding numeral. The 

 figure is inverted. 



FlG. 64. Elatostemma sessile. Transverse section or a bud. 

 II-IV the foliage-leaves (foliage-leaf / is only indicated by the 

 axillary stipule sti) ; a, 6, c, are the opposite leaves of the pairs 

 to which 7, //, and /// belong and are reduced to scales, and 

 have no axillary stipule. 



many species of Elatostemma these rudimentary leaves are said to 

 be entirely suppressed and then a leaf-position would be found, quite 

 like that which is seen in Ulmus. The several species of Elato- 

 stemma appear to differ from one another in their whole construction. 

 I observed one species common at Buitenzorg, I did not identify it, 

 which was plagiotropous and anisophyllous even on the chief shoot of 

 the seedling ; others again I noted possessing a creeping stem from 



1 Weddell regarded this leaf as a stipule. This is an error. It is, although stipule-like, a leaf 

 which has been arrested at an early stage of development and has no leaf-lamina. At an early period 

 it becomes covered with hairs like the primordia of the large leaves, and this is a character which the 

 stipules do not possess. 



