174 Alexander W. Evans, 



becomes the actual bounding layer and often appears continuous 

 with the persistent part of the outermost layer. The cells of this 

 second layer are only a trifle wider than those of the outermost layer, 

 averaging about i6 /x. The interior cells are mostly 100-180 /x long ; 

 in the median portion they average about 30 fx in width, but toward 

 the margins they are considerably wider, averaging about 45 /x. 

 In cross-section the increase in the size of the cells in passing 

 inward is fairly gradual, especially in the median portion. The 

 interior cells are all thin-walled. The cells of the two or three 

 outside layers, however, with the exception of the short-lived 

 median band, have their walls slightly and uniformly thickened. 



On each side of the axis, at intervals of 1-3 mm., branch- 

 rudiments or branches are given ofif. The branch-rudiments 

 (Fig. 10, B) are in the form of very short bilobed projections, 

 with the apical cell in the indentation between the lobes. The 

 branches spread obliquely and are mostly 0.7-1 mm. wide. Except 

 for differences in length the branches are remarkably uniform and 

 do not dififer in any essential respect from the axis, so far as their 

 histological features are concerned. Many of the branches, in 

 fact, represent new axes and show long-continued growth, with 

 numerous branch-rudiments and branches of their own. The 

 majority, however, stop growing when they have attained a length 

 of 1-3 mm. and these branches are either simple or show only one 

 or two still shorter branches or branch-rudiments. 



Stephani described his Aneura Negeri as sterile, but the material 

 studied by the writer shows two female inflorescences, one of which 

 has been fertilized (Fig. 10, A). The branch in each instance 

 is very short and spreads oblicjuely from the main axis. It is 

 fleshy and slightly bilobed at the apex, one of the lobes being par- 

 tially covered over by the axis. The wings, which do not show 

 very clearly, are apparently one cell wide and vaguely crenulate 

 or denticulate from projecting cells. About four archegonia are 

 present in the unfertilized inflorescence, and the other shows an 

 old battered "calyptra", clavate in form, 4.5 mm. long and 0.75 

 mm. wide. The surface is roughened from peeling-off cells, and 

 no sign of a corona is visible. 



In its histological features R. Negeri ])ears a certain resemblance 

 to R. Spegazziniana and R. specfabilis, with which Stephani 

 associated it. All three species show one or more layers of small 



