THE ORIGIN OF SEX IN PLANTS 23 



to be the case. Such advantages as follow from the 

 pooling of the hereditary factors of the two sexual cells 

 can still be secured by such means, notwithstanding the 

 loss of motility of the enlarged female gamete. Thus 

 the nett advantage lies with the plant : for without 

 sacrificing the benefits that follow from syngamy it can 

 still secure for its offspring the probability of successful 

 germination. Conjugating organisms, with their equiva- 

 lent gametes which are usually small, may be regarded 

 as a plant-proletariat that produces numerous offspring 

 with little physiological capital ; so that each individual 

 when produced must depend chiefly on its own efforts. 

 The organism which shows differentiation of its gametes, 

 with an enlarged, well-nourished egg, is like a capitalist, 

 whose progeny starts life well furnished with an inheritance. 

 To them the initial struggle for life is less intense. Other 

 things being equal, ultimate success should lie with the 

 latter : and a study of the vegetable Kingdom from this 

 point of view shows how successful the results of the 

 differentiation have been. 



All of the higher forms of Vegetation have the sexes 

 fully differentiated. They have progressed on the- footing 

 of the relatively large, immobile, well-nourished egg. 

 In many of them the comparatively small spermatozoid 

 is still motile ; but in the Higher Flowering Plants even 

 this motility is lost, in accordance with circumstances 

 which will be explained in the second Lecture. At the 

 moment no more can be done here than to state the 

 leading facts of sexuality as seen in the Land Vegetation, 

 which stands higher in the scale of Evolution than the 

 water-plants hitherto discussed. Two further examples of 

 sexual propagation must suffice for the present, viz. a 

 Fern, as illustrating the lower types of Land- Vegetation ; 



