46 INTRODUCTION TO CRYPTOGAMIC BOTANY. 



the smaller ones are not of the same import as the larger, a. The 

 smaller spores which consist of a single cell, within a proper 

 envelope, remain some months after being sowed without 

 much change. Gradually, however, their protoplasm generates 

 a number of cells, each of which contains a spiral spermatozoid. 

 The smaller spores, then, which do not germinate, are ana- 

 logues of antheridia, though they resemble in their mode 

 of development _ordinary pollen grains, which are clearly 

 homologues of spores. They are, in fact, of far greater dignity 

 than the pollen grains of Conifers, though, in pomt of fact, 

 homologous with them. The grumous fo villa of these latter, 

 in every respect except in function, differs from the ultimate 

 contents of the small spores, h. The larger spores consist also 

 originally of a single cell,rbut in the process of growth they 

 acquire an envelope, and have a disc applied to their inner 

 surface consisting of a double row of cells. This exists while 

 they are yet in the mother-cell from which they are derived. 

 The formation of this disc is the only thing in the shape of 

 germination which they exhibitj After some months,!^similar 

 disc is formed within this, and the upper disc contains^ a nu mber 

 of little flask-like bodies, commjmicating aliovejffiith_tlie-.QpaL 

 air, in which, by impregnation, . an _ em^;jo__is_ developed_ 

 from a single cell filhng the base of the body, whi ch is 

 called an Archegonium. I am not aware that the formation 

 of the embryo-sac within the nucleus of Phsenogams has 

 been observed accurately.* It is quite certain, however, 

 _|hat, it is not a raere cavity formed in the cellular tissue 

 of the nucleus, for if so, it would never become free "an3~' 

 project beyond its aperture, as it does in Crucifers, much 

 less would there be a plurality of such sacs as in the same 

 plants, sometimes branching and assuming a variety of forms.f 

 We have here, then, a plurality of embryo-sacs, a tendency 

 to become free, and at the same time to germinate. We do 

 not know how these multiplied embryo-sacs arise, whether from 

 the division of one cell, or the sweUing out of distinct con- 



* Schleiden says that it is the dilatation of a central cell, and such it 

 probably is. A direct proof of this is evidently one of extreme difficulty. 



t Tulasne in Ann. d. Sc. Nat, s6r. 3, vol. xii. p. 21. 



