ON THE HIGHER CRYPTOGAMOUS PLANTS. 121 



that of the Ferns and Equisetacese ; and if the existence of sexes be a fact, 

 we have here a dioecious condition as contrasted with a monoecious condi- 

 tion in the two last-named families. Hofmeister here again assumes that 

 the pro-embryo developed from the large spore is an intermediate genera- 

 tion between the two perfect forms of tlie plant. 



It is rather difficult to decide upon the real analogies of these structures with 

 those of the flowering plants. The resemblance of structure is so close between 

 the pistillidia of the Mosses and Hepaticae, 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 flowering 

 plants, but rather to ovules ; if this be the case, the sporangium must be 

 considered the analogue of the perfect plant in the Fern, &c., and the 

 leafy stem as the analogue of the pro-embryo of the Ferns, &c. The 

 pistillidium of the Mosses can indeed liardly be regarded as analogous to the 

 fruit of a flowering plant, as in that case the spores would be ovules pro- 

 duced long after fertilization ; and on the other hand, if we consider the 

 pistillidia of the Moss as an ovule, which it might be, analogous to that of 

 the Coniferae, — in which a large number of embryonal vesicles or rudiments 

 of embryos are produced after fertilization on the branched extremities of 

 the suspensors, — then we seem to lose the analogy between the product of 

 the pistillidium of the Moss and that of the ovule of the Fern, unless we 

 would regard the entire plant of a perfect Fern as analogous to the ovule of 

 a Conifer. 



Perhaps the time has hardly come for us to arrive at any conclusion on these 

 points. The phaenomena in the Ferns and Equisetaceae, as well as in the 

 RhizocarpcK, Lycopodiaceae, and Isoetaceae less strikingly, seem to present 

 a series of conditions analogous to those which have been described under 

 the name of " alternation of generations " in the animal kingdom, and seeing 

 the resemblance which tlie pistillidia of the Mosses have to the ovules of the 

 other families, we can hardly help extending the same views to them ; in which 

 case we should have the remarkable phaenomenon of a compound organism, 

 in which a new individual forming a second generation, developed after a 

 process of fertilization, remains attached organically to the parent, from which 

 it differs totally in all anatomical and physiological characters. It is almost 

 needless to advert to the essential difference between such a case and that of 

 the occurrence of flower-buds and leaf-buds on one stem in the Phanero- 

 gamia, as parts of a single plant, yet possessing a certain amount of indepen- 

 dent individuality. These are produced from each other by simple extension, 

 a kind of gemmation ; while the Moss capsule, if the sexual theory be cor- 

 rect, is the result of a true reproductive process*. 



In conclusion, I may remark, that these anomalous conditions lose their 

 remarkable character to a great extent if we refuse to accept the evidence of 

 sexuality which has been brought forward here. If the structures are all 

 products of mere extension or gemmation, the analogies which have been 

 supposed to exist between them and the organs of flowering plants all fall 

 to the ground. But believing that the hypothesis of sexuality is based on 

 solid grounds, I am by no means inclined to allow the difficulty of the ex- 



* Moreover we have an analogy to the increase by huds in the innovations by which the 

 leafy stems of the Mosses are multiplied, both in the earliest condition, where a number of 

 stems are developed from the byssoid mass produced by the spore, and afterwards by gem- 

 mae on the stems and leaves, as in the Liverworts also. The byssoid mass produced by 

 the Moss-spore has usually been called the pro-embryo, but it is evidently not analogous to 

 the bodies termed pro-embryos in the Ferns, Lycopodiaceae, &c. &c. It would almost seem 

 to constitute a third member of a series of generations. 



