76 Henderson — Comparative Study of Pyrolaceae and 



winged petioles, and large orbicular crenulate, prominently 

 veined, dark green, leathery blades. 



In P. elliptica, there occurs the same succession of scale 

 leaves and foliage leaves, ending with three scale leaves at 

 the base of the flowerstalk, this arrangement being character- 

 istic of the genus. The leaves are evergreen, lasting from two 

 to three years. They have narrowly winged petioles, shorter 

 than in P. rotundifolia, and large elliptic crenulate blades, which 

 are smaller in size, less prominently veined, lighter green, and 

 less leathery than in P. rotundifolia. 



In P. secunda, the leaves are evergreen and smaller than in 

 P. elliptica. The petioles are shorter, the blades much less 

 leathery, and lighter green in color. 



In P. minor, the leaves are evergreen and of the same size, 

 or smaller than in P. secunda. 



In P. chlorantha, the leaves are evergreen and of the same 

 size or smaller than in P. minor. 



In P. aphylla Holm (30) has described and figured a rosette 

 of small green leaves "provided with a distinct petiole and 

 a blade varying from lanceolate to broadly ovate, obtuse or 

 slightly pointed." Below these occur a few scale leaves, and 

 above them the bud for the next year's inflorescence. The 

 green leaves are deciduous and are produced in alternate years 

 with the flowering shoot. For this reason some have incor- 

 rectly described the plant as aphyllous. Lateral inflorescences, 

 which arise in the axil of a scale, occur, and are therefore not 

 preceded by green leaves. 



In Moneses uniflora, the arrangement of alternating whorls 

 of scales and leaves is similar to that of the genus Pyrola. The 

 leaves, though not at all leathery, are evergreen for two to 

 three years. They are small elliptic, acute, with a serrate margin. 



In Pterospora andromedea, the leaves are reduced to brown- 

 ish scales arranged closely together, in fact overlapping at the 

 base of the flowering axis, but becoming more distant from 

 each other toward the region where flowers are produced. Those 

 at the base of the stem are small and somewhat triangular. 

 Further up the axis, these become narrower and longer, and 

 finally they decrease in size toward the flowers. Those at the 

 base are smooth on the outer (lower) surface, but toward the 

 top of the flower axis they become more and more hairy gland- 



