268 
DOUGLAS HOUGHTON CAMPBELL 
the structures of the older sporophyte, foot, seta and capsule, are 
presumably developed from the terminal cells of the young embryo, 
as they are in other similar forms, e. g., Podomitrium, Pallavicinia, etc. 
Figure 4, A, shows a young sporophyte in which the basal region 
constitutes a haustorium made up of large cells. The embryo at this 
Fig. 4. A. Young sporophyte showing the large haustorium,^^, X 84. B. A 
single cell of the haustorium, showing the large nucleus, X 375- C. Cells from the 
upper part of the sporophyte, X 375. 
stage closely resembles that of certain species of Pallavicinia, 1° but 
the haustorigtl cells are relatively smaller and more numerous. The 
cells of the haustorium have very much larger nuclei than those of 
the upper part of the embryo (fig. 4., B, C). In the later stages of 
development these haustorial cells become very much compressed 
by the rapid growth of the foot of the young sporophyte, which evi- 
dently replaces them as an organ of absorption. A similar condition 
was noted by the writer in Podomitrium. 
As the sporophyte grows the lower portion enlarges slightly to 
form the rather indefinite foot (fig. 5, C, /) while the terminal region, 
1° Campbell, D. H. and Williams, F. A Morphological Study of Some Members 
of the Genus Pallavicinia. Stanford University. 1914. 
Campbell, D. H. The Morphology and Systematic Position of Podomitrium. 
Amer. Journ. Bot. 2, 199. 1915. 
