M. Miiller on the Development of the Lycopodiaceae. 39 



gonal, with horizontal walls (figs. 1, 3) . The apex of this organ 

 is often bifurcated (fig. 4) ; the forks however at their apices 

 pass gradually into cells like those we have before met with 

 (figs. 1, 3). By a transverse section we find that the interior 

 also is filled by layers of delicate parenchymatous cells (fig. 2). 

 The same is seen in a longitudinal section (fig. 5), in which it 

 may be clearly perceived, the external layer of cells regularly 

 inclosing the remaining mass of cells. The apex is prolonged 

 out into a few layers of cells (fig. 5) ; finally into a single one 

 (fig. 1). Moreover the cells of the swollen, expanded base are 

 filled with a finely granular, somewhat reddish matter, which 

 however is only developed here into membrane-substance y since 

 it probably forms new cells to multiply the numbers, whereby 

 the bulging circumference of the basis is enlarged. No other 

 kind of cell-contents is present (fig. 1). 



This singular organ is present in all stages of the plant's 

 existence. In the terminal bud of the youngest '^ germ " it is 

 already perfect, and is situated between the bud of the branch and 

 the bud-envelope (PI. II. fig. 6 ^). It is again met with in every 

 successive leaf, in the large as well as in the '^ intermediate.^' 

 In the terminal bud even of the perfect branch it is produced 

 soon after the development of the leaf from the stem, and is 

 always placed between them. Equally constant is it between 

 the oophoridium and the antheridium and their involucral 

 leaves. It is particularly large between the oophoridium and 

 its involucre. 



With respect to the development of this organ, it appears both 

 in the terminal bud of the " germ " and that of the branch as a 

 more or less circular plate (PI. III. figs. 6, 7, 8, 8 a). In the 

 first-named bud its very delicate cells are already filled with 

 that often-mentioned reddish substance, by means of which the 

 organ becomes more extensively developed (figs. 6, 7). In the 

 second the plate is frequently quite transparent and devoid of 

 that substance (fig. 8). The plate, now of equal thickness all 

 over, then extends itself upwards into an attenuated neck, 

 rounded at the top (PI. III. figs. 9, 10). This is usually more 

 transparent than the base of the organ, which also in the leaves 

 of the terminal bud of the branch soon becomes filled with the 

 same reddish contents. Through this elongation, however, the 

 base appears as if thicker ; this indeed is quite natural, as it has 

 not yet become extended. But the cells speedily become deve- 

 loped in this part of the organ on the side next to the leaf. By 

 this means the organ acquires a bulging form in this situation 

 (PI. III. fig. 5 a)y while the side turned toward the axis of the 

 branch is usually much more perpendicular (fig. 5 Z>). As soon 

 as the general form is perfect, the top of the organ becomes 



