M. Miiller on the Development of the Lycopodiacesc. 109 



XIV. — On the Development of the Lycopodiaccae. 

 By Kaul Muller*. 



[With five Plates.] 

 [Continued from p. 40.] 



§ 5. The perfect Plant. 



We have here to consider: — 1. the axis of the branch) 2. the 

 roots of the branch ; 3. the leaves', and 4. the organs of reproduc- 

 tion, 



1. The axis of the branch. The germinating plant divides, as 

 we have already seen, normally into two branches, consequently it 

 is bifurcated. The same kind of division is exhibited throughout 

 the whole gi'owth of Lycopodium denticulatum. The branches are 

 always dichotomous, the vascular bundle always dividing in this 

 manner. 



The branches, as is known, are compressed on the upper and 

 under sides. 



Interiorly they are composed of numerous layers of cells. At 

 first two circular spots are found in the centre, lying at some 

 distance from each other. In these situations are produced the 

 vessels, which as usual are surrounded by long," prosenchymatous 

 cells (PI. III. fig. 12). They lie within the latter as a simple and 

 almost circular group. From these vascular bundles proceed out- 

 ward a number of tubular cells which finally come in contact 

 with a layer of delicate and short parenchymatous cells. These 

 last are the only cells throughout the whole axis of the branch 

 which as yet contain any of the '^ cell-contents '^ (fig. 12 «), 

 which consist of very small yellowish green granules, more or less 

 collected into groups. The whole is inclosed by several layers of 

 thin-walled, transparent and short parenchymatous cells. The 

 layers situated most externally (the cortical layers) consist of cells 

 which are always somewhat more elongated and more slender, 

 and are not hexagonal, but have the form of parallelograms. 

 Toward the terminal bud, the cells of the axis all become smaller 

 and more crowded, till at last they look like mere globules 

 (fig. 13). 



All these conditions vary in the most manifold way in the 

 stems of the other Lycopodiaceae. This is especially the case with 

 regard to the grouping of the vascular bundles. The structure 

 of the cell-membrane also is very variable among them. These 

 however are conditions of which a further examination would be 

 extrinsic to my design. Most of them indeed are already known, 

 and only individual cases require pointing out. The development 



* From the ' Botanische Zeitung,' Aug. 28, and Sept. 4, 1846. Trans- 

 lated by Arthur Henfrey, F.L.S. &c. 



