21 



ripening ; in the cleistocarpous mosses this is provided for by the 

 absence of a lid, and in the Polytrichacese by the discoidally expanded 

 summit of the columella closing the mouth. In Buxhaumia the lid 

 remains long attached to the mouth, while it is firmly joined to the 

 columella by the vascular bundle running through it, and only becomes 

 loosened by the rotting of the fruit ; the endostome also forms a high, 

 firm, conical membrane, with a small aperture at the apex, formed by 

 the falling away of the vascular bundle ; through this narrow opening, 

 however, the spores cannot escape, even if the erect position of the 

 fruit would allow it, and thus they are forced to remain in the capsule. 

 In time, the upper half of the capsule separates at the lateral seam, — 

 like a bivalve fruit, as it was described by old authors, — and thus a 

 free exit is made for the spores." 



I follow C. Miiller, Zukal, and Lindberg in excluding Wehera Ehrh. 

 {Diphyscium Mohr.) from this family, for the two genera have nothing 

 in common but the external form of the capsule, while the highly 

 developed seta, absence of stem and degraded leaves of Buxbamnia 

 are totally opposed to the absence of a pedicel, distinct stem, and 

 highly-developed leaves seen in Wehera. 



Besides the European species of Buxhaumia, the only others 

 recorded are B. Javanica C. Muell. apd B. Tasmanica Mitt., the 

 former very close to B. aphylla, the latter equally near to B. indusiata, 

 and probably not specifically distinct from them. 



By the depressed asymmetric capsule, so unusual in mosses, we 

 have some indications of affinity with the exotic genus Dawsonia, 

 and a further snpport to the position of the family among the 

 Polytrichoidece, though it must be admitted that the cilia of the 

 peristome of Buxbaumia do present a few transverse articulations. 



BUXBAUMIA. Haller. 



(Enum. Stirp. Helv. i, p. lo (1742).) 



Plants very small, scattered. Leaves extremely minute, broadly 

 ovate or oblong, coarsely serrated, laxly areolate with oblongo- 

 hexagonal echlorophyllose cells, or palmato-laciniate, the lacinis and 

 basal cells becoming altered by age into long filaments, and finally 

 into dense radicular tomentum. Inflorescence dioicous. Male plants 

 very minute, few-leaved, the bracts not laciniate, antheridia one or 

 two, subglobose, with few paraphyses. Female plants presenting 

 10-12 perichsetial bracts which after impregnation develop cilia. 

 Calyptra very small conico-cylindric, generally cleft at the side ; 

 capsule on a thick verrucose seta, with a short, erect neck, oblique, 

 ventricose, ovate, depressed above, with a conico-cylindric operculum. 



