homologous Alternation of Generations in Plants . 361 
De Bary’s sense, not to regard them as phylogenetically 
identical with those of the archegoniate series, but rather as 
a parallel development — -a similar response to a somewhat 
similar stress of circumstances : the rationale of formation of 
carpospores is the multiplication of the species without a 
corresponding repetition of the sexual process, in fact an 
economy of sexuality together with a uniform distribution 
of the effect of the sexual process : this may doubtless have 
been of importance both in the Archegoniatae and in the green 
filamentous Algae, and it is reasonable to think that both 
series may have developed in a somewhat similar direction, 
though by a distinct evolutionary sequence. 
The same line of reasoning will also apply to the case of 
the Florideae, which are undoubtedly less closely allied to 
the Archegoniatae than are the Confervoideae : in these there 
is a more obvious interpolation of an intermediate growth 
between the successive gametophytes. The gametophytes 
may reproduce their like by tetraspores (gametophytic bud- 
ding), which are often borne on distinct sexual plants ; ulti- 
mately, as the result of fertilization of the procarps (borne 
often on distinct sexual plants), a growth of a more or less 
extensive nature is produced either from the actual cell 
fertilized (Nemalion> Batrachospermuwi), or from an adjoining 
cell or cells of the procarp ( Lejolisia , &c.), or even more indi- 
rectly, from adjoining procarps to which the fertilizing effect 
is handed on ( Corallina , Dudresnaya , &c.), and this results in 
the formation of carpospores. We may allow the use of this 
term, and recognise in the carpospores the result of a growth 
succeeding a sexual act, and differing in form and mode of 
production from the tetraspores : a comparison of different 
members of the Florideae will also suggest how such develop- 
ments may have resulted from an interpolation of a develop- 
mental stage in a manner to some degree comparable to the 
interpolation of the sporophyte in the archegoniate series. 
It is hardly necessary to point out that much the same 
is the case for the Ascomycetous Fungi, and that the series 
of ascogenous hyphae (e. g. in Ascobolus or Eurotium\ upon. 
