The Development of Fossombronia longiseta, Aust. 
BY 
HARRY B. HUMPHREY, B.S. 
Leland Stanford Jr. University, California , U»S.A. 
With Plates V and VI, and eight Figures in the Text. 
TJ OSS OMBR ON I A longiseta occurs in great abundance in the imme- 
JL diate neighbourhood of Stanford University, as well as in other parts 
of the state. All material used in the preparation of this paper was collected 
by the writer within or near the university campus. The work was taken 
up at the suggestion of Dr. D. H. Campbell, whose valuable advice and 
guidance is much appreciated. I am also indebted to Dr. Geo. J. Peirce for 
a number of helpful suggestions pertaining to certain physiological problems 
in their bearing upon Liverworts, and to Dr. A. A. Lawson for instruction 
and advice relative to methods, microtechnique and points of cytological 
interest. 
With the exception of the classical work of Leitgeb 1 no comprehensive 
study of any member of the genus Fossombronia has yet appeared. Occu- 
pying as it does a position between the purely thallose J ungermanniaceae 
such as A neura and Metzgeria and the higher foliose types, it was thought 
that a careful study of the species F. longiseta might disclose some in- 
teresting morphological relationships. 
Habitat and External Characters. 
Our species of Fossombronia appears to be a very adaptive one as to 
habitat, for while the most thrifty and largest plants are found along moist 
and well-shaded north-east banks or hill-sides, it is not infrequently found 
associated with Sphaerocarpus cristatus and Anthcceros Pearsoni, growing 
on soil exposed to the sun to a greater or less degree during the day. 
It occurs in great abundance under the somewhat open growth of the 
university arboretum, and this habitat seems greatly to enhance the 
development of antheridia and archegonia at the expense of the vegetative 
growth. Howe 2 reports it as producing stems 6 to 15 mm. long, and 
sometimes once dichotomous, but we have occasionally found it under 
1 Leitgeb, vol. iii, pp. 105-20. 2 Howe (’ 99 ), p. 8r. 
[Annals of Botany, Vol. XX. No. LXXVII. January, 1906.] 
G % 
