no MORPHOLOGY 
sporophyte. In considering the sporophytes of liverworts in general, 
it is evident that from Riccia to Antlwceros there is a progressive sterili- 
zation of sporogenous tissue, the sterilized tissue forming the vegeta- 
tive structures. Among the Anthocerotales three additional features 
of the sporophyte are noteworthy: (i) the beginning of independence 
by the development of green tissue; (2) the beginning of sporangia by 
the breaking up of a continuous sporogenous mass into separate smaller 
masses ; (3) the establishment of a sterile axis by the transfer of the spo- 
rogenous tissue to the outer region of the capsule, which suggests the 
beginning of a region for the development of vascular tissues and the 
beginning of superficial sporangia. 
It should be understood clearly just what is meant by such a state- 
ment as that the Anthocerotales have certain features suggestive of the 
pteridophytes. It does not mean that the pteridophytes have been 
derived from the Anthocerotales or from any of the bryophytes. It 
means simply that the sporophyte of the Anthocerotales represents 
a stage of progress like one through which the pteridophytes may have 
passed during their evolution. The plant groups as we know them now 
certainly did not give rise to one another, but they can be used to sug- 
gest general stages of progress, of whose real details and connections 
we know nothing. 
2. MUSCI 
General character. This is the great group of bryophytes, both 
in numbers and in specialization. While the liverworts may be the 
more interesting from the standpoint of suggestions as to pbylogeny, the 
mosses are the representative bryophytes in our present flora. For so 
great a group it is very well defined and consistent. Mosses are widely 
distributed, being found in all habitats except salt water, and are 
especially conspicuous in colder regions (alpine and arctic), where they 
form a prominent feature of the vegetation. They seem to have been 
derived from liverworts, and their sporophyte characters, at least, 
suggest a possible connection with Anthocerotales ; while in certain 
features of the gametophyte the resemblance to Jungermanniales is 
more evident. Three groups are recognized: (i) Sphagnales, (2) An- 
dreaeales, and (3) Bryales. 
(i) SPHAGNALES 
General character. These are the bog mosses, all of which belong 
to the single genus Sphagnum. They are large, pale mosses, character- 
