558 INTRODUCTION TO CRYPTOGAJVIIC BOTANY. 



638. The germination of the spores, and the evolution of 

 the sporelike bodies of the antheridia in Lycopods, do not 

 take place till some months after they are committed to the 

 ground. The germination of the spores (Fig. 124) consists in 

 the formation of a prothallus by cell-division, adherent to and 

 confluent with the spores, as in Marsileacece, or penetrating 

 their cavity, without the protrusion of threads as in Ferns or 

 Mosses. This cellular matter may occupy only a small portion 

 of the cavity (Fig. 124, d) of the spore, or it may fill it en- 

 tirely. Archegonia soon appear in the prothallus, generally 

 in greater number than in Marsileacece, and the embryonic 

 mass is formed from a cell at the base of the archegonium 

 (Fig. 124, h). The embryo is usually situated transversely, 

 with an evident opposition of the ascending and descending 

 points of vegetation, and two leaves are ultimately formed 

 (Fig. 126), which have a close resemblance to Cotyledons. 

 The stems, when developed, consist of a mass of thick walled, 

 often dotted, cells, inclosing one- or many fascicles of scalariform 

 tissue, which send off branches to every leaf and bud. The 

 scalariform tissue is accompanied by fine elongated, or some- 

 times coarser, cells, which are occasionally distinctly reticu- 

 lated, as in Lycopodium Selago. There is no crossing of fasci- 

 cles as in Endogens, and there are no medullary rays. The 

 stem, in fact, approximates closely to that of ferns, to which 

 these plants are nearly allied ; but the fascicles of vascular 

 tissue are confined to the centre. Their relations to Conifers, 

 though indicated by many curious resemblances, are strictly 

 analogical. Though the pollen grains of Conifers undergo 

 curious changes after they are separated from the anthers, 

 these changes do not result in the formation of spermatozoids 

 or anything homologous ; and though there is much resem- 

 blance between the formation of the archegonia and embry- 

 onic body in Lycopods, and that of the corpuscles and 

 embryos in Conifers, the origination of the spores from mother 

 cells in the former is so distinct from that of the ovules in 

 Conifers that homology is out of the question, and we have, 

 therefore, mere analogies to build upon, which, however 

 curious, indicate no afiinity ; a fact confirmed by the great 



