No. 435-] 



AXTITHE TIC VERSL r S HOMO LOGO i \S. 



l6 7 



the elevation of the receptacles, which usually does not begin 

 until after the fertilization of the archegonium, is not more 

 intimately associated with spore-dispersal than with the need of 

 chlorophyll-work. In most Marchantiaceae the seta is very little 

 developed, and the elongated stalk of the receptacles probably 

 takes its place. 



If one were looking for gametophytic structures which most 

 nearly simulated the organs of the leaf}- sporophyte it would be 

 among the lower thallose Jungermanniales, and not among the 

 true mosses, that one should look. The extraordinarily fern-like 

 aspect of certain thallose liverworts like certain species of Aneura 

 and Hymenophytum 1 recalls at once some of the Hymeno- 

 phyllaceae with fan-shaped, dichotomously veined leaves. These 

 fern-like liverworts develop a rhizome-like stem, having flattened, 

 dichotomously branched green shoots, curiously like a small fern 

 leaf. Structurally, however, they are in all respects like the 

 prostrate thallus of other species. 



Now it is conceivable that when the sporophyte reached the 

 stage when it first developed a leaf, the latter should tend 

 to assume a form suggesting the expanded, dichotomously 

 branched lamina, so characteristic of nearly all the lower liver- 

 worts, which I assume represent the ancestral type, from which 

 the terns have been derived. - 



When Professor Coulter speaks of the subordination of chlo- 

 rophyll-work to spore-formation among the Kryophytes, I sup- 

 whole Sphagnum swamps without a sporophyte, and Lunularia 

 multiplying almost exclusively by vegetative buds, illustrate this. 



