LYCOPODITTM. 355 



sively larger and more lobed; (3) the gradual decay of the 

 prothallus, as the young Fern-plant obtains its own food 

 by means of its roots and leaves and therefore becomes 

 independent of the food- supply it had at first drawn from 

 the prothallus by means of the foot. 



These points may be clearly seen in specimens decolor- 

 ised with alcohol, and made transparent with chloral 

 hydrate, potash, or some other clearing reagent. 



Also cut longitudinal sections of prothalli with young 

 Fern plants, and note the relative positions of cotyledon, 

 stem, root, and foot. 



LYCOPODITJM. 



499. General Characters. The Common Club Moss 



(Lycopodium clavatum), the largest as well as commonest 

 of the five British species, grows chiefly on heaths, moors, 

 and mountain- sides. Note 



(a,) The creeping stem, tough, flexible, and much 

 branched some of the branches creeping, others ascending 

 and growing erect. 



(Z>) The roots, arising from the lower side of the stem 

 often one root at each point of branching, but also at other 

 parts of the stem and showing more or less distinct 

 dichotomy (forked branching). 



(c) The small simple lance- shaped leaves, crowded and 

 overlapping on the creeping stem and branches, arranged 

 spirally or in whorls or in both ways, each leaf having a 

 finely toothed margin and ending in a long hair- point 

 which curves in towards the stem at the ends of- the 

 branches all the leaves tend to curve strongly upwards. 



(d) The erect branches which are slender below (owing 

 to the leaves being here small, scattered, and closely 

 pressed to the stem), but at the top, after branching into 

 two or three, expand again into the cylindrical or club-like 

 cones. 



(e) The sporangia, kidney- shaped and almost sessile 



