142 



CLUB MOSSES. 



the middle, having been gradually developed into this form through the stages 

 represented in the annexed figures (Figs. 271 275). To see the peculiar organs, 

 the disk-like cellular plate must be carefully laid face downwards upon a slip of glass, and 

 washed clean, gently removing the grains of soil, with a camel-hair pencil, from among 

 the rootlets. When placed under the microscope, a number of projecting cells (Fig. 

 276 b] are generally found scattered about the frond. These are seen to be again filled 

 with minute vesicles (Figs. 277 and 278), which escape by the bursting of the protrud- 

 ing cell, either spontaneously or by slight pressure on the glass covering the object 

 (Fig. 279). As the vesicles emerge they burst also, and from them springs out a spiral 

 thread-like body, thickened at one end, and furnished with cilia, as represented in the 

 woodcut (Fig. 280). These, the so-called animalcules, swim about with great rapidity, ! 



Fig. 282. 

 agnitied. 



Fig. 283. 



Fig. 280. 



Fig. 280. One of the sp 

 Fig. 281. Side view of an ovule. 

 Fig. 282. The summit of the same, seen from above. 



Fig. 283. Side view of an ovule from Suminski, representing the embryo-cell at the bottom of 

 the cavity. 



shooting forward, and continually whirling round on their own axes. To see them 

 clearly, their motion must be stopped by adding a little solution of iodine. 



On the thickened part of the frond, near the notch, are to be found, in most cases, 

 not always, cellular structures of larger size, and more complicated (Fig. 281). They 

 consist of conical papillae, with cellular walls, containing a cavity in the centre, as 

 represented in the Figures 282 and 283. 



In Club Mosses (Lycopodiutri), the containing reproductive organs are also called thecse, 



Fig. 284. Fig. 285. 



Fig. 284. The Lycopodium Aphodium, or Club Moss. 



Fig. 285. A, full-grown plant of Marsilea pubescens; B, spore (opened), natural size; and C, 

 section of spore magnified, with the contained spores. .Both of the Olnaria globulifera. 



