* 
Evolution in the Plant Kingdom. 329 
The next phase in the sex-reproduction, the one naturally 
expected in the fourth group, is the protection of the male and 
female cells or organs. Set apart heretofore in form and function, 
they are not protected ; but in the fourth group this is gradually 
and at length very completely provided for, as indicated by the 
group name, Carpophytes, or “ plants with spore cases.” In cer- 
tain members of the group—those which look towards Oöphytes—the 
male and female cells are at first as naked as in Odphytes, and if 
the spore passed into the resting stage the plants would belong to 
that group ; but the spore, as soon as formed, proceeds to develop 
other structures, and, along with the female cell in which it is con- 
tained, develops a complex structure called a spore-case, and this is 
the resting stage. 
Summing up the advance made in the fourth group, we find 
male and female cells distinct in form ; the latter finally protected ; 
and the sex-spore ceasing to be the resting stage, and becoming an 
evanescent phase which passes directly into a complicated structure, 
which itself is the resting stage. Subsequently, from this compli- 
cated structure, or “spore-case,” forms like the parent plant are 
produced by means of so-called spores, not formed by sex-union, 
but by ordinary cell division, and for that reason called asexual 
Spores, They are simply reproductive bodies cut off from the 
parent stock, and are chiefly for the dissemination of the plant, 
no more a product of the sex act than the buds used in grafting or 
the “slips” in transplanting ; but they are the “ spores” commonly 
spoken of among cryptogams, and their name is legion. The 
essential difference between sexual and asexual spores cannot be too 
Strongly pointed out, for they have led to endless confusion of 
ideas. Note now the relation of things in this fourth group. The 
sex-spore produces the structure called the spore-case, which in turn 
produces asexual spores by ordinary cell division, which in turn 
reproduces the original parent. In this group, therefore, in the 
effort to protect the progeny the resting stage was pushed forward, 
ma that condition of things known as “ alternation of generations ” 
originated. As a result, we have in a single life-cycle two plant 
Phases, each producing spores, but in a very different way. One 
phase bears the sex-organs and produces the sex-spore, and hence is 
called “ the sex-plant ;” the other is produced by the sex-spore, 
no sex-organs, produces asexual spores, and hence is called — 
