NOTES ON SPH^ROCARPUS. 77 



great development of the vegetative parts with a correspond- 

 ing reduction in the number of sexual organs. Leitgeb ^ 

 mentions similar forms occurring in his cultures as adventi- 

 tious buds but these seem to have been small and sickly, 

 while my plants grew vigorously and exceeded in size the nor- 

 mal ones. This was especially the case with the male plants 

 which were several times larger than the normal form. The 

 dichotomous branching is very conspicuous in strong con- 

 trast to the very obscure branching of the normal plants 

 where on account of the excessively short branches the tlial- 

 lus appears unbranched and almost orbicular in outline. The 

 dichotomy is entirely similar to that in other similarly 

 branched liverworts, and as in these, there is a conspicuous 

 "median-lobe" (Fig. 9. 1.) between the branches. A remark- 

 able characteristic of these plants was the presence of regu- 

 lar marginal lamellae, which in origin and position are 

 directly comparable to the leaves of Blasia or Fossombro- 

 nia, and seem to be strictly homologous organs. The margin 

 of the normal plant is almost completely undivided and 

 shows little or no traces of similar structures. It may be 

 remarked, however, that the recently described Geothallus, 

 which seems to be the nearest relative of Sphasrocarpus, has 

 well-marked leaf-like marginal lamellae. 



Another peculiarity of these plants is the late appearance 

 of the sexual organs. Ordinarily these are evident very 

 early. Leitgeb '^ mentions cases where he observed them 

 upon plants only .1 mm. in diameter. In our plants they were 

 often not formed until after the first dichotomy of the thallus 

 which occurred when the plants had reached a length of 

 several millimetres. They were in most cases produced 

 sparingly, although some specimens finally developed them 

 in normal numbers. 



Where the ripe spores were seen they were united in 

 tetrads. 



6 1. c, p. 65. PI. IX., fig. 20. 

 7 1. c, p. 73. 



