119 



larly circumstanced, as in the mosses, Lycopodineae and Cy- 

 cadece. (In these latter plants small buds not unfrequently 

 occur at the base of the stem between the scales. Rep.) 



In the Ophioglossea M. Mohl compares the whole theca, in 

 reference to its organization, with the anthers of a phaenoga- 

 mous plant. The apex represents more or less distinctly the 

 apex of a leaf; the receptacles of the sporidia are mere cavities 

 in the tissue of the leaf, and the axis of the theca corresponds 

 to the middle portion of a staminal leaf contracted to a con- 

 nective. 



InBotrychium the sporangia already become more independ- 

 ent ; they are perfectly separated from each other, a case 

 which M. Mohl compares to the formation of the anther in the 

 genus Geonoma. He also recognizes in the sporangia of all other 

 ferns, which develope their fruit on the under surface of the leaf, 

 an analogous formation with the theca of the anthers. At least 

 it is clearly proved that the morphological functions hitherto 

 ascribed to the capsules in ferns are erroneous, and M. Mohl 

 finds another reason for his view in the formation of sporidia 

 in primitive cells which are subsequently reabsorbed. No great 

 weight can be laid on this last reason, for at present several 

 other cases are known where the formation of new cells takes 

 place in original cells. A series of objections which might also 

 be brought forward against the analogy between the sporan- 

 gium of a fern and the theca of an anther are refuted at length. 



The ingenious idea that the capsules of ferns consist of me- 

 tamorphosed leaves, the midrib of which forms the ring of 

 the sporangium, appears to have been first advanced by C. H. 

 Schultz ; altogether M. Mohl seems to pay too little regard to 

 the writings of that philosophical botanist, from whom the 

 sporangia of the lower plants have already long ago obtained 

 their morphological signification. Thus for instance the spo- 

 rangia in Equisetum have originated from the metamorphosis 

 of the foliaceous members of the stem, as those of the Poly- 

 podia from the metamorphosis of the leaves ; and consequently 

 the former also correspond to the articulation of the stem, the 

 nodes of which have formed the capsule-shields, and the 

 sheaths of the leaves the loculi of the capsule ! 



There are greater difficulties in the signification of the spo- 

 rangium in Lycopodium, yet in this case M. Mohl seizes on 



