THE DEVELOPMENT OF ORGANISMS 787 



So in the male sex, the stamen was interpreted as also a spore- 

 bearing leaf, more developed than that which is reduced to a carpel. 

 Its pollen grains were identified, not as themselves the simple and 

 ultimate fertilising elements of previous and still popular belief, 

 but as microspores developing their greatly reduced prothallus as 

 the familiar pollen-tube of the fertilisation process. In this "germina- 

 tion of the pollen grain", its nucleus divides: one of the resultants 

 remaining vegetative, but the other descending to the pollen- tube 

 tip, and thence making its way to unite with that of the ovum. 

 Here, then, is the fullest conceivable reduction of the male genera- 

 tion : yet that this is a true homology has been confirmed by the 

 more recent discovery of active and motile antherozoids produced 

 at the tip of the pollen tube (male prothallus) in Cycads, gymno- 

 sperms more primitive than the conifers. So, in brief retrospect, 

 we see how the alternation of generations is continued morpho- 

 logically and physiologically in "flowering plants"; so that these 

 are now understood as true Sporophytes, substantially corre- 

 sponding to the ferns and Lycopods we know, though greatly 

 reducing and incorporating their sexual generation into the most 

 profound concealment of all the motherings of nature, so that 

 what was thought the simplest and most obvious of sex-pro- 

 cesses, and conspicuously phanerogamic, turns out to be the 

 most disguised and ultra crypt ogamic reduction. The evolutionary 

 bearing of all this is not a little impressive, for the apparently utter 

 separateness of so-called flowering and flowerless plants is thus 

 satisfactorily bridged over and rendered intelligible. And this not 

 only morphologically, but also in physiological terms, as an evolu- 

 tionary reduction of the sexual generation for both its sexes, though 

 the female especially. Yet this sex influence profoundly penetrates 

 back (perhaps with hormones we may some day distinguish?) 

 into the respectively female and male spore-bearing leaves, the 

 carpels and stamens which we call the essential organs of the flower. 

 It even influences the floral envelopes into beauty, most markedly 

 the petals; not infrequently also the sepals, and even in some 

 cases the mothering leaf of the flower — the bract — as well. 



This body of discovery as to the real nature of the flower- 

 obviously so evolutionary in its interpretation — ^is the greatest of 

 compensations for the comparative poverty of the palaeontological 

 record, which has as yet yielded so much less of clear and continuous 

 evolutionary series than we now possess for various animal types 

 and races; and indeed, from its perishable nature, it can hardly 

 be expected to do so to any such convincing extent. Yet vegetable 

 palaeontology, too, goes on yielding more and more illustrations of 

 various beginnings of flowers and even seeds, and often in plants 

 which long seemed but on the level of ferns or their allies : so taking 

 all evidence from living forms and past forms together, the botanist 



