150 ARTIFICIAL FERTILISATION 



by pure accident. But for the most part now, I make clean 

 work of it, and remove all other expanded flowers on the seed- 

 bearing plant, and allow no kindred one to be near. 



3d. Do not be in a hurry to effect your cross ; wait till you 

 find that the stigma is fully developed. In many plants this 

 is shown by a glutinous exudation on the summit, as in the 

 Ericaceae, the Onagraceae, &c. In othe/ orders, such as the 

 Geraniacese and Malvaceae, it is indicated by the feathery 

 expansion and recurvature of its separate divisions. 



4th. The next thing is to obtain properly -ripened pollen- 

 grains from the male plant. This is done by carefully watch- 

 ing when the anthers burst, otherwise the insects may be before 

 you ; and so active are they, especially on such favourite food 

 as the pollen of the Rubus tribe, that, to get at it all, I have 

 found it necessary to encase the opening blooms in muslin 

 bags till the pollen was ripe and ready for use. Do not use, 

 as is generally recommended, the camel-hair pencil, which, 

 applied often and indiscriminately, may and often does convey, 

 with the foreign, some insidious grains of native pollen, which, 

 however few, are prepotent, and wholly neutralise the former. 

 Take, where that can be obtained and afforded, the entire 

 bloom of the intended male, and give the slightest brush with 

 all its anthers over the stigma, or all the stigmas, if more than 

 one, of the intended female. I will give my reasons for this 

 by-and-by. You may use for experiment, in some cases the 

 long, and in some the short, stamens. To those of the proper 

 dimorphic form I have made some allusion elsewhere; they 

 occur in the species of Primula, and in some of the species of 

 the Linum tribe (as to both of which, see Darwin's most 

 remarkable papers in the 'Proceedings of the Linnaean Society'). 

 Such anthers, at least two long and two short ones, occur in 

 the two orders of the Linnaean class Didynamia, on which I 

 may have a suggestion to offer hereafter, for I think something 

 interesting may be worked out of this form. In cases where 

 the anthers are few, as in the Linnaean classes Diandria, Trian- 

 dria, &c., you may use small pincers a bit of wire so twisted 

 as to form that implement, to carry in the pocket, is by far the 

 handiest. I have used such an instrument all along, and find 

 it better than any other form. In some tribes, the better to 

 secure against invasion by insects, such especially as in some 

 of the Rosaceae having large discs, a muslin bag may be used, 

 so as effectually to exclude them ; I use it constantly in the 

 Rubus tribe immediately after emasculation, taking it off and 

 replacing it after the cross, and keeping it on thereafter till the 

 cross has set. 



