M. Miiller on the Development of the Lycopodiacese. 29 



coats. The exterior is very thick and made up of numerous 

 cells, the walls of which are wholly confused together, so that 

 they are often scarcely perceptible on the surface of the section. 

 This thickening is common to the whole coat, the cells of which, 

 by the incessant deposition of new matter in their interior, be- 

 come homogeneous plates. Yet some species differ so much in 

 this respect, that the cells are not completely thickened, but still 

 exhibit some cavities, as in L. articulatum. The continued depo- 

 sition of membranous substance usually causes the external coat 

 of the spore to exhibit elevations on its outer surface. They occur 

 especially upon walls of the cells as anastomosing ridges of irre- 

 gular form [L. articulatum) ; in other spores where the walls of 

 the cells have become almost indistinguishable, as wart-like bodies 

 (L. selaginoides), or as large, compact papillae [L. pT/gmceum). In 

 L. articulatum there are, besides these larger elevations, still 

 smaller papillae scattered over the whole surface. They constitute 

 a special thin membrane which may be detached from the cells 

 lying beneath. 



The inner membrane on the contrary is usually perfectly struc- 

 tureless and of equal thickness in all parts ; it is not so firmly 

 adherent to the outer membrane as to prevent its being detached 

 from it. I have only found the inner membrane different from 

 this in the spore of a single species, namely in L. gracillimumy 

 that is indeed if I did not confound it with the outer membrane, 

 which I do not believe. In this case, beneath the outer thick 

 membrane lies a layer of parenchymatous cells of tolerable size, 

 which could be separated from the former. I saw nothing of 

 any other layer, like that which is present as the inner mem- 

 brane in all the other spores ; this therefore must be regarded as 

 the peculiar inner layer, although it is not clear to me how this 

 inner membrane can consist of an independent layer of cells. 



In general this membrane is formed of a more or less granular 

 substance, which is particularly evident in L. articulatum. 



The contents of these spores consist of a granular mass which 

 is contained free within the inner membrane. The granules 

 are perfectly round, distinct from one another, transparent and 

 of very variable though always small size. They stil] remain in 

 this condition after being kept for years, as I can state, in con- 

 firmation of Bischoff, with regard to L. selaginoides. This in- 

 quirer says* of them, that they appeared to him to consist of ve- 

 sicular cells, and following him, Schleiden f speaks also of a deli- 

 cate cellular tissue. On the other hand, I must remark, that to 

 me these granules appeared to be not nearly so like small cells as 

 compact grains, since on treating them with strong tincture of 



* Ut sup. p. 110. t Grundz. ii. p. 82. ed. 1. 



