1911] The Ottawa Naturalist. 173 



we have two kinds of Club Moss, viz., those without running 

 stems and those with running stems. 



The first class comprises L. selago and L. lucidulum, the two 

 species we have seen reasons for considering primitive; and as 

 though to compensate for the defects of their upright terminal 

 growth, they have both devised the expedient of detachable 

 branches. Near the apex of the annual growth, just above the 

 region of fertile sporangia, 2 or 3 deciduous gemmae or vivi- 

 parous buds are formed. These detach themselves from the 

 growing axis or are blown away by the wind and form new plants 

 by striking root on contact with the ground. It is a purely 

 vegetative form of reproduction and dispenses with the inter- 

 mediate stage of the prothallus. It has its analogy in the bulbils 

 of Cystopteris bulbifera. In many plants it is the roots that thus 

 reproduce, e.g., the tubers of the potato; and in one species of 

 Club Moss, L. cernuum, a more or less tropical kind, are found 

 similar subterranean nuclei for plant -multiplication. 



These gemmae represent the plant's supreme effort at land- 

 grabbing ; their attempt to jump a claim. This is borne out by a 

 curious fact I have noticed in L. lucidulum: the deciduous buds 

 are centrifugal in nature ; they nearly always are thrust forth on 

 the side remote from the older and prostrate stem ; if they do not 

 always face in the direction towards which the plant has been 

 struggling forward, they never look straight back towards the 

 centre from which the plant started. In structure they seem to 

 be modified leaves, for they take their regular place in the whorl 

 of leaves, each being in its whorl a substitute for the normal leaf. 

 Usually even when as many as three gemmae are produced, they 

 are all in the same whorl, or at most in two successive leaf- 

 whorls. 



So far we have seen how the Club Moss by adopting a more and 

 more complex system of branching and rooting has progressed 

 as a plant ; we have yet to note the steps of advance it has made 

 as a sporophyte. These steps are still on the principle of division 

 of labour and consist in the separation of the vegetative from 

 the reproductive tract. I said a little way back that all the 

 various kinds of differentiation subserved the two functions of 

 nutrition and reproduction. Of course the life-ambition of the 

 plant is to perpetuate its kind; but to be fertile it must first be 

 vigorous, and if you look at a young Club Moss you will see that 

 its first care is the output of a vegetative system, a leafy shoot 

 that will support the later output of sporangia. 



In the archetype postulated by Prof. Bower, each of the 

 leaves all round and all up the simple shoot performs a vegetative 

 function and supports a sporangium at its base. The first change 

 is by the lower leaves becoming abortive and no longer bearing 



