A. Henfrey on the Higher Cryptogamous Plants. 37 
The great differences depend on the position in time and space 
of the organs, in the different classes, and the nature of the im- 
mediate product of the so-called “embryo-sac,’” the large central 
cell of the pistillidia and * ovules.” Fee 
Iu the Mosses and Hepatic the pistillidia occur upon the plant 
when the vegetative structure is perfect,—and the immediate pro- 
duct of the great cell is a sporangium. If a process of fertiliza- 
tion takes place here, we may regard the antheridia and pistillidia 
as analogues of the anthers and pistils of flowering plauts; the 
sporangias of their fruits; or with Hofmeister we may regard the 
phenomena as an instance of an “alteration of generations,” 
where the pistillidium would be looked upon as an ovule, 
ducing (in the sporangium) a new individual of totally different 
character from that developed from the spore (the leafy moss plant 
in the usual acceptation of the term 
In the Ferns and Eyuistaceee, we find the spores producing a 
frondose structure of definite form, upon which are developed 
antheridia and pistillidia or “ovules.” Here then we seem to 
ave one generation complete, and the new development from 
the pistillidiam or “ovule” appears in a totally new form, produe- 
ing stem and leaves which have a distinct individual form and 
existence, and produce the spores after a long period upon tempo- 
Tary parts of the structure, on the leaves; and by no means cease 
to exist when those are matured. Here we seem to havea real 
“alternation of generations,” and Hofmeister compares the whole 
permanent plant of the Fern or L'quisetum to the sporangium of 
the Mosses and Hepatic. In all the other families, the Lycopo- 
diacee, Isoétacee, the Rhizocarpee, the pro-embryo is a very 
transitory production, and is developed from a different spore from 
the spiral filaments. ‘This pro-embryo is clearly analogous to 
that of the Ferns and Equisetacee ; and if the existence of sexes 
be a fact, we have here a decious condition as contrasted with a 
Monecions condition in the two Jast-named families. Hofmeis- 
ter here again assumes that the pro-embryo developed from the 
large spore is an intermediate generation between the two perfect 
forms of the plant. 
It is rather difficult to decide upon the real analogies of these 
Structures with those of the flowering plants. The resemblance 
of strueture is so close between the pistillidia of the Mosses and 
1epatices, and the “ovules” of the other Vascular Cryptogams, 
that they must be regarded as analogues, and then the former 
Could not well be conceived to be analogous to the pistils of flow- 
ering plants, but rather fo ovules; if this be the case, the sporan- 
8'um must be considered the analogue of the perfect plant in the 
ern, &c., and the leafy stem as the analogue of the pro-em 
