STRUCTURE.] ANTHERIDS OF LYCOPODS, 101 



much he thinks certain, " that the antheridium can be 110 

 product from a leaf, since it is formed from the axis contem- 

 poraneously with the leaf. As little can we regard it, with 

 Bischoff, as formed by the growing together of leaves. 

 Besides, Mohl has already triumphantly refuted this view. 

 But that we have to do with a metamorphosed bud, on the 

 contrary, cannot be disputed; since the first, rounded antheri- 

 dium-spherule possesses all the peculiarities of a bud, epider- 

 mis and a formative cell-contents. The only question is, 

 whether we are to regard this bud as analogous to those so 

 often met with in the axils of the leaves." He considers it a 

 lateral bud (the bud of a twig), which is only distinguished 

 from the terminal bud of the branch developed into the 

 oophoridium by the circumstance that the latter is a principal 

 branch, which possibly was capable of a more extensive deve- 

 lopment into branch and foliaceous organs, while the twig 

 which is developed into an antheridium is but a small particle 

 of such a main branch. " That it is a twig, appears to me to 

 be shown by the internal structure of the fruit-axis, since 

 from its central vascular bundle are given off real lateral 

 branches to each bud (antheridia) . Yet it must be freely 

 admitted, that the vascular bundle does not actually run into 

 the peduncle of the antheridium, but terminates before reach- 

 ing it, and it is merely elongated cellular tissue which proceeds 

 from the vascular bundle into the peduncle." (See the whole 

 paper illustrated with figures in the Annals of Natural History, 

 vol. xix.) 



PEPPERWORTS (Marsileacea3) consist of plants differing so 

 much from each other that the genera require to be examined 

 separately. 



Of Marsilea the most complete account has been given by 

 M. Fabre. In Marsilea Fabri the fructification consists of a 

 two-valved coriaceous involucre (sporocarpium, Endl.), having 

 its valves held together by a central line continuous with the 

 stalk : this involucre seems to be a modified leaf. From the 

 stalk there rises a mucilaginous ring to which adhere minute 

 ramifications of the spike, terminating in oblong spikes 

 covered with fructification. After a time the mucilaginous 



