JOHNSON: A REVISION OF THE SECTION BORAPHILA 5 



Previous writers have placed considerable emphasis on caulescence in 

 their classifications, but since this character was found to vary considerably 

 it is here regarded as of little taxonomic value. Within certain limited 

 groups the petals and leaves are distinctive, and this is also true of the 

 filaments and the inflorescences. The petals of the section Arabisa, for 

 example, are distinctive of that section ; so too are the leaves of the section 

 Hydatica, although very similar leaves occur in the section Catthophyllum.'^ 

 The filaments and the inflorescence of Calthophyllum are unmistakable. 

 Taken as a whole, however, these characters are only secondary in com- 

 parison with the carpels and glands. The same may be said of the calyx 

 segments, which soon become strongly reflexed in the hypogynous species, 

 but in the others the degree of reflexion may be greater or less, dependent 

 upon the degree of adherence of the receptacle to the ovary. In the latter 

 case they often become reflexed with the growth and expansion of the 

 ovary, and are therefore not very reliable for taxonomic purposes. Seed 

 characters are valuable criteria of relationship within certain groups, but 

 appear to have received little attention. Unfortunately most collections 

 are deficient in seed material. The distinctive character of the seeds is 

 well shown in the section Arabisa. And in the difficult section Micranthes 

 the seed characters sometimes proved to be the last resort in establishing 

 affinities. 



To turn now more particularly to a discussion of the classification pro- 

 posed in this paper : as stated on a preceding page the sections are grouped 

 into two major divisions on the characters of the hairs; the sections of the 

 first division having "uniseriate," those of the second "multiseriate," hairs. 

 Two lines of development are to be noted in the sections of the first division. 

 On the one hand we have a series of three sections in which the ovary is 

 wholly superior, namely Hydatica, Calthophyllum, and Aulaxis. In addition 

 the carpels are more or less united, two lines of evolution being indicated, 

 one in which the carpels are more or less bottle-shaped and erect, or spread- 

 ing from the base at maturity, the other in which the upper free portions 

 of the carpels are elongated and widely spreading — in V-shaped fashion — at 

 maturity, while the lower capsular portion becomes somewhat constricted 

 toward the base. The former condition is found in Hydatica and Cal- 

 thophyllum, the latter in Aulaxis, in which also the gland surrounds the 

 carpels as a thick girdle from the base to the middle. Marked differences 

 in the glands serve to distinguish Hydatica and Calthophyllum. In Hydatica 

 the gland lies close to the base of the carpels as a thick fleshy collar, and the 



* Calthophvllum, sect. nov. Ovarium librum; carpidia conica ad basin minime contracta ct 

 coaliU singula infra medio glandula dilatata cincta; folliculi elliptico-oblongi distinct! inferne et 

 superne inaxime contract!, stylis hrevibus attcnuatis, stigmatibus parvis; filamenta primum clavata 

 demum maxime elongata filiforn^ia: f-epala rcflexa. 



