130 HYBRIDISING AND CROSS-BREEDING. 



and as it is possible that a pollen-tube from either kind of 

 pollen might have simultaneously entered the ovule, these seeds 

 might have contained two embryos of a different nature ; such, 

 however, was never observed to be the case. 



Imperfect or Partial Fertilisation. The following remarks 

 on this portion of the subject are from the late Hon. and 

 Rev. Dean Herbert's paper in Hort. Soc. Jour., vol. ii. p. i 

 et seq. : 



" Whoever tries to raise mule Alstroemerias from A. aurea by 

 some cognate species will find, under favourable circumstances, 

 every flower produce a full-sized perfect capsule, though he 

 may fail in obtaining the least enlargement of the ovules. A 

 mule raised by Mr Bidwill between Passiflora c&rulea and 

 P. ony china flowered this summer in my conservatory, and pro- 

 duced of itself, to my surprise, two fine plump fruits, two inches 

 long, of a bright orange colour, there being no other Passiflora 

 in flower at the time on the premises. On opening its beau- 

 tiful fruit it proved to be empty as a bladder, the outer coat 

 of the fruit only having been fertilised, in consequence of the 

 weakness of the cross-bred pollen. [Cucumbers often produce 

 fruits in this way, without any trace of fertile seeds.] In other 

 attempts at cross-breeding, or in plants that do not make seed 

 freely in our climate, he may find not only a perfect capsule, 

 but seeds grown to a full size, though containing a perishable 

 lymph, and no sound kernel,. In others he may find the seed 

 either of an undue texture and substance, or, if apparently 

 good, deficient in embryo. In some cases, as in the very ex- 

 traordinary one first noticed by Mr Brown with respect to 

 Hymenocallis, the seed having no discoverable embryo when 

 first ripened, acquires one after lying for some weeks or months 

 on the earth. It follows, therefore, that a continued operation 

 of the pollen must be necessary to produce all these requisites 

 for the formation of a good seed. It has been said that when 

 the ovules are fertilised the outer coat or capsule begins to 

 swell. This does not appear to be true ; for the capsule often 

 becomes perfect, though the ovules do not seem to have 

 become fertilised at all. It seems, therefore, a process inde- 

 pendent thereof, whether simultaneous, antecedent, or pos- 

 terior ; so must the fertilisation of the seed-coats and of the 

 albumen be, since they may grow without an embryo : and 

 some mysterious process must be continued to vivify the 

 embryo at a later period, since it can elude the microscopic 

 research of Mr Brown in a seed so large as that of Hymeno- 

 callis. I have cut open seeds of Hymenocallis an inch and a 

 half long, and found no visible embryo, but a large cavity ; yet 



