86 Prof. F. Schmitz on the 
parent plant itself into a spore-fruit, which, by the develop-. 
ment of carpospores, brings back the whole developmental 
cycle again to the starting-point. This is exactly the same 
course that is displayed by the development of the Liverworts 
and Mosses,—the same sequence of alternating generations as 
in those cases. Thus it becomes easy in the course of deve- 
lopment of these simplest Florides to recognize the alternation 
of generations of the Archegoniata, which, as is well known, 
we have accustomed ourselves to regard as the typical mode 
of vegetable development, so much so, indeed, that only the 
recognition of this alternation of generations in the individual 
case explains and renders intelligible the course of develop- 
ment in the group of plants in question *, 
But these simplest Floridee are approached most closely 
and distinctly, as has been shown above, by the other forms 
with more complicated fructification, and precisely by this 
distinct approximation enable us also to recognize clearly and 
distinctly in their development the above alternation of genera- 
tions, although it has been here somewhat complicated by the 
intercalation of the second sexual act +. 
But, independently of this complication, the above typical 
alternation of generations makes its appearance quite undis- 
turbed and distinctly recognizable in the course of develop- 
ment of many Floridee. In many other forms, however, 
still further complications of it occur, the vegetative generation 
dividing, as in the true mosses, into prothallium and leafy 
plant (Batrachospermum &c.). In numerous other forms, 
moreover, the tetraspores or bud-formations of various kinds 
are developed in the vegetative generation as accessory organs 
of increase, whether they are produced upon the sexual indi- 
viduals themselves (Cruortopsis cruciata, Duf., Petrocelis Ru- 
prechti, Hauck, &c.) or confined to special neutral individuals 
(as in most Floridee). 
Lastly, in many Floridez there seems to be associated with 
the above typical alternation of generations (corresponding to 
* That in such an explanation of the course of development of a group 
of plants we have to do with a perfectly analogous process, as in the 
explanation of the more complicated forms of flowers of Phanerogamia, 
which are explained and made intelligible (see Schmitz, ‘ Die Familien- 
iagramme der Rhéadinen’) by comparison with other previously known 
flowers, will not be hard to see upon consideration. 
+ In these forms of the Floridese (Gleosiphonia &c.) we can if we like 
distinguish series of three generations, as here the female sexual cell of 
the simpler Florideze (Nemalion &c.) is replaced by two cells, the carpo- 
gonium and the auxiliary cell, and between these a new third generation 
is intercalated. 
