132 PHILOSOPHICAL NOTES ON 



of pliaenogams Avas originally a cladophyl, and that its midrib 

 (now the stem) budded out into branches, like those of Delesscria. 

 In cases where a midrib had not yet developed, the edges of the 

 cladophyl budded out, as in Fucus pahnatiis of Stackhouse, and 

 Z>' Urvillea potatorum of Harvey, &c. Among phrenogams we 

 have the same occurring in Phyllocactus hiformis and others, and 

 Phyllocladus glauca (conifer). In the latter we have a fine 

 example of the main leaf-branch aborting, and in its stead a 

 branchlet (the axillary bud) taking its place. The true leaves 

 are minute and scale-like, that is, they have aborted into stipels. 

 In their axillap,, cladophyls have developed, as secondary branches, 

 and again in the axillai of the teeth of these the inllorescence 

 develops. 



The expansion of the petiole of the Australian Acacias is 

 nothing but a partial reversion in the young leaves, and a total 

 reversion in the adult leaves, to the seaweed phase, although 

 botanists have chosen to call them pliyllodes. The Acacia leaf 

 is often a combination of the cryptogamic and the phsenogamic 

 leaf. In Phyllanthus Augustifolius, Ruscus, Phyllocactus^ Phyllo- 

 cladus, and others, the phgenogamic leaf proper has degenerated 

 into a mere trace. Although they have reverted to the leaf -stem 

 of their distant ancestors, they have retained the inflorescence of 

 their nearer progenitors. 



To an evolutionist it is hardly necessary to quote any more 

 examples in support of the theory that the leaves of phsenogams 

 are distinctly traceable to the cladophyls of seaweeds, such as 

 Delesseria and others. I, therefore, need not do more than refer 

 the reader to the works of Esper, Harvey, Thuret, and others, on 

 seaweeds. 



We can now trace the cladophyl a little further in phaenogams. 

 I will first refer again to Gigartina lanceolata (Fig. 16) and Fucus 

 palmatus, marginifer (Fig. 20). These show us the origin of 

 teeth, teeth glands, which so many plants possessing teeth have, 

 and of ovules on the margins of carpels. 



With regard to marginal ovules, Le Maout and Decaisne 

 ('* Syst. of Bot.," p. 68) say : " Some German and French botanists 

 regard the carpellary leaf as a protective organ merely, denying 

 that it has the power of producing buds,* and limiting this power 

 to the floral axis." 



* The reader should note that they call ovules, htids. 



