JOHNSON: A REVISION OF THE SECTION BORAPHILA 39 



same grounds, apparently, that Tausch included 6". nivalis, but in the case of 

 6'. davurica he was probably misled by inadequate material, as the species 

 properly belongs in the section Hydatica. Ledebour (18) combined the sec- 

 tion with Arabisa of Tausch on the non-stoloniferous habit. Torrey and 

 Gray (31) included S. erosa Pursh {S. micranthidifolia Haw.) with some 

 hesitation. 



Hooker (16) made no mention of this species but included a new one 

 which he had named Saxifraga reflexa. Finally Small (27) adopted 

 Micranthes (Haw.) as a generic name for a combination of Haworth's 

 genera Rohertsonia, Dermasea, and Aulaxis, and Rafinesque's (24) genus 

 Steiranisia. In that sense Small's genus was synonymous with the sections 

 Micranthes and Hydatica of Tausch and his followers. The result was 

 an aggregation of species of widely different floral characteristics. 



The section Micranthes contains the majority of those species with a deep 

 receptacle in which the tendency toward epigyny has advanced the farthest 

 and which are further characterized by the conspicuous, fleshy, discoid gland 

 which is elevated a considerable distance above the base of the calyx, and 

 which persists as a distinct flange around the carpels at maturity. The 

 gland is the most distinctive characteristic of the section. 



In Saxifraga pennsyhanica and 5. calif arnica the gland is more elevated 

 than in the other species. Other minor distinctions appear here and there. 

 A reference to the plates will show the striking similarities in the glands 

 and carpels, particularly in S. integrifolia, S. nidifica, and v9. montanensis. 



The carpels are distinct to the base but are connected laterally by the 

 adnate receptacle and at least by the lower portion of the gland. In some 

 cases as in S. pennsyhanica, S. Sierrae, and S. oregana, the receptacle 

 does not keep pace with the growth of the carpels so that as the follicles 

 are pushed apart at maturity the receptacle is compressed and gives the 

 appearance of a completely hypogynous condition. 



As a whole the section presents the most difficult problem in the entire 

 series. Polymorphism appears to be a general characteristic and compli- 

 cates the situation. In no other group, it appears from the herbarium speci- 

 mens, have botanists been so at variance on the question of species. 



Two main tjrpes of petals occur, the narrowly lanceolate and the orbicu- 

 late. Between these there are many variations. The strictly lanceolate 

 type is restricted exclusively to the eastern species, namely to S. pennsyl- 

 vanica and its allies. The extreme orbiculate type is represented by 5". 

 californica and 5". napensis. Curiously enough the orbiculate type is as 

 constant at this extreme as the lanceolate type at the other. In the group 

 reprefsented by S. mtegrifolia the variations of petal- form are perplexing 

 in the extreme. 



