474 : BOTANICAL GAZETTE [JUNE 
incompletely developed sporangia ‘“‘in order that these facts may have their 
true weight in the general discussion of vegetative and fertile regions of the 
primitive leafy sporophyte.” It is possible to look upon an imperfectly 
eveloped part as either upon the up-grade (nascent) or on ‘the down-grade 
(evanescent) of development. These terms “nascent” and ‘evanescent’ 
may be applied to either the ontogeny or the phylogeny. As an advocate of 
the antithetic theory of alternation of generations, Professor Bower does not 
accept the recapitulation theory. Hence the question of priority in the his- 
tory of descent cannot be settled summarily by the sequence in the ontogeny. 
Neither an infinite number of transitional forms, nor experimentally the con- 
version of a sporophyll into a foliage leaf proves anything more than an inti- 
mate relationship between the two. It in no way settles phylogenetic priority. 
_ Acclue, the writer urges, may be obtained from the bryophytes. A com- 
parison of the most primitive sporangium (Riccia) with more complex types 
_ indicates the intercalation of a seta before the spores are formed, and leads 
one to conclude that the seta does not precede spore development phyloge- 
ey but that in more complex capsules the spore development is 
rded- by an intercalated stage; in short, progressive sterilization and 
oe aun of vegetative parts takes place to provide for the growing 
_ demand for nutrition. In the genus Lycopodium a comparison of closely 
related forms and a study of the individual part has led the author to believe 
development is analagous to that of the bryophytes. By 
mn basal : sporangia have become functionless and ves- 
a porangia at the apex of the cone he regards as 
a 
re also discussed from the same standpoint. 
jes that although abortive parts are less common in plants than 
’ have played a less i important role in theories of plant mor- 
z — should as = ons out of account altogeter a 
“Mem. 
aparative mnsology 0 of the Rubiaceae. 
