[126]

Upper straight Leaf Crinum capense

young almost straight leaf

Right hand

Tracing II

From 3˚ P.m on 22d to 10˚,15' on 25'

[126v]

(42) 598

 

Chapter 0 9

and the extent to which their offspring suffer by this process; and some such correspondence might have been expected if self-sterility had been acquired on account of the injury caused by self-fertilisation. The fact of individuals of the same species of parentage differing greatly as they do in their degree of self-fertility sterility is likewise opposed to such a belief; unless indeed we suppose that certain individuals have been rendered self-fertile to favour intercrossing; whilst other individuals have been rendered self-fertile to ensure the propagation of the species. The fact of self-sterile individuals appearing very only occasionally as in the case of certain species, of Libuta Lobelia fulgrans, does not countenance this latter view. But the strongest argument against the belief that self-sterility has been acquired to prevent self-fertilisation, is the immediate and powerful effect of changed conditions in either causing or removing self-sterility. We are not therefore justified in admitting that this peculiar state of the reproduction system has been gradually acquired through natural selection; but we must look at it as an incidental result, dependent on the conditions to which the plants have been subjected, like the ordinary sterility caused in the case of individ animals by confinement; and in the case of plant