218 Evans: Notes on genus Herberta 



observed. These are apparently never produced unless the growth 

 of the main male axis is brought to an end in some way, possibly 

 through the failure of an androecium to proliferate, possibly 

 through an accident of some sort. In either case a branch tends 

 to take the place of the main axis and to assume its functions, 

 precisely as a ventral branch of a sterile axis or a subfloral innova- 

 tion would do. When, therefore, an androecium is borne on a 

 branch of this character, its position can not be regarded as typical. 



These considerations gain in significance when H. Hutchinsiae 

 is compared with H. dicrana (Tayl.) Trevis., a closely related 

 species of the Himalayas. The writer's knowledge of this species 

 is largely based on specimens received from Levier and collected 

 by Decoly and Schaul {782) near Kurseong in Sikkim-Himalaya, 

 in May, 1899. These specimens contain both male and female 

 plants and are of especial interest because they served as the basis 

 for Schiffner's statements regarding the androecia of H. dicrana* 

 He notes their occurrence on the ends of branches, their small 

 size, the small number of bracts (about four pairs) which they 

 bear, and the fact that they are sterile at the apices. The branches 

 which bear the androecia are ventral and vary greatly in length. 

 Sometimes the development of the antheridia brings the growth 

 of the branch to an end, but a sterile proliferation of the androecium 

 often occurs. The formation of the male branches seems to be a 

 perfectly normal process and is not preceded by a cessation of 

 growth of the main stem as in H. Hutchinsiae. It follows, there- 

 fore, that what occurs abnormally in the northern species has 

 become normal in the Himalayan species. It should be noted, 

 however, that ventral androecia are not absolutely constant even 

 in H. dicrana. One example was observed where the androecium 

 was borne on a main stem; it had somewhat larger bracts and 

 bracteoles than the ventral androecia but resembled them in other 

 respects. Aside from the difference in the position of the andro- 

 ecia, H. dicrana resembles H. Hutchinsiae very closely. The 

 leaves and underleaves, the bracts and bracteoles, and the perianths 

 are much the same in the two species, although the divisions of the 

 leaves in H. dicrana usually are less strongly curved. The latter 

 species, moreover, is slightly larger, the leaves are less crowded 

 and the thickening of the cell-walls is less pronounced. 



* Hedwigia 50: 148. 1910. 



