Primulaceae. 203 



this development is however rare. The plant (from Herschell 

 Island) depicted in fig. 19, A, has, however, a more erect 

 growth, and this is the more characteristic form of speci- 

 mens from this locality. There was a considerable amount 

 of clay and sand amongst the withered leaves of the three 

 lower rosettes (fig. 19, A), and it seems probable, that the 

 plant has grown on a spot, where, under certain conditions, 

 its vegetative organs were periodically covered by deposits, 

 thus causing the plant to assume a more erect manner of 

 growth, necessary for maintaining life. 



The leaves do not seem to retain their assimilative 

 function beyond one period of growth, and the leaves de- 

 veloped during the previous summer were nearly always 

 withered before the following spring. The withered leaves 

 are fairly resistant, and they may remain on the plant for 

 several years before crumbling away. 



Special bud-scales are not formed, but the young leaves, 

 which are very hairy, especially on the margins, protect 

 the growing point by bending across it. There are two fairly 

 well differentiated types of axial shoots: one has a thicker 

 elongated internode and a densely leaved rosette ; the other 

 has a thinner axis and fewer leaves in the rosette, and its 

 growth never terminates by the development of a peduncle. 



As regards the anatomy, there is a marked difference be- 

 tween the long-jointed internodes of these two types, which 

 will be dealt with later. 



The flower. The size of the corolla seems to vary 

 greatly (fig. 20, A and B). I found it largest on plants from 

 Herschell Island and from Wajgatsch, a diameter of 12 mm 

 being attained ; it was distinctly smaller (6 — 8 mm) on plants 

 from other habitats. The colour is whitish-yellow, the 5 

 small projections narrowing the throat, having a more pro- 

 nounced yellow colour. According to H. Müller, who tho- 

 roughly describes the biology, these throat-scales change their 



