48 buxbaumiacejE. 



the ordinary leaves having been produced later in order of time 

 and very possibly having arisen by modification of the perichaetial 

 bracts. Thus not only in type of peristome, but also in the 

 general habit and morphology, we may probably look upon this 

 Order, and especially the genus Buxbaumia, as an archaic type 

 which has survived in something like its primeval form. Even in 

 Diphyscium, the true leaves though perfectly developed are quite 

 an inconspicuous part of the plant beside the fruit and perichaetial 

 leaves. 



I have retained the two genera under this order, which is 

 perhaps the most usual arrangement, partly on account of the 

 general resemblance of the capsule and its internal structure, and 

 partly on account of the great similarity of the peristomes, a 

 marked and real similarity, though perhaps less so than would 

 appear at first sight. The form and structure of the leaf in 

 Diphyscium is hardly, I think, sufficient in itself to outweigh these 

 important affinities and justify its separation from Buxbaumia. 



The presence of delicate articulations in the outer teeth, and 

 the minute structure of these and the inner peristome (as pointed 

 out by Philibert, Rev. Bry. t 1889, pp. 4, sqq.), indicate an approach 

 on the part of the Buxbaumiaceae to the Arthrodonteae, but the 

 origin of the outer teeth in several series of concentric cell-layers 

 constitutes a sufficient ground for placing the Order among the 

 Nematodonteae, though at the end of the series. 



7. BUXBAUMIA Haller. 



Plants very minute, scattered, stemless. Leaves indistinguish- 

 able from the perichaetial bracts, all minute, ovate or lanceolate, 

 palmate with ciliar productions of the marginal cells, nerveless, 

 without chlorophyll. Male plant (v. Goebel, in Flora, 1892, Suppl. 

 pp. 92, sqq.) among the vaginular tomentum, a concave, shell-like 

 leaf, enclosing a single globose stalked antheridium, similar to 

 that of the Hepaticae. Mature fruit on a stout rough seta, large, 

 somewhat obliquely egg-shaped, with the narrow end pointed and 

 slightly recurved, inserted obliquely on the seta with a short neck, 

 flattened on the upper surface, brown. Outer peristome of one 

 or several rows of irregular filiform teeth, inner a pale tubular 

 membrane in the form of a truncated cone, longitudinally plaited 

 like the folds of a fan, with 32 plicae. Dioicous. 



/Capsule plano-convex, much flattened above, glossy .,, aphylla 



\ Capsule scarcely flattened, paler, epidermis splitting when dry *. ' indusiala 



