SECONDARY EFFECTS OF FERTILIZATION. 



42a 



integuments, in the carpels, and, finally, in the flowering axis which bears the whole 

 of the structures concerned. These changes, which become manifest in the form of 

 growth, are executed on a definite plan in every plant, and depend on the peculiar 

 constitution of the protoplasm. The aim of these growth-changes is not difficult 

 to determine. The new organism which has arisen from fertilization must be 

 adequately provided for the future; it is detached sooner or later from its parent- 



Fig. 318.— Seeds with winged and hairy appendages. 



1 Dehiscent fruit of Briodendron; the seeds embedded in a hairy investment are visible between the valves. 3 Dehiscent fruit 

 of Qossypium herbaceum; the mass of seeds is contained in a hairy investment protruding from the valves. ^ Seed of Aspen 

 iPopulus tremiUa) with silky appendage. * The same seed stripped of its silk. » Winged seed of Lepigonum marginatum. 

 < Longitudinal section of the winged seed of Yochysia. 1 Winged seed of Cinchona, s Longitudinal section of this seed. 

 • Winged seed of Cedrela Toona. i" Longitudinal section of same. ^> magnified. (Partly after Baillon.) 



plant, and has to establish itself in a new place. The embryo requires special 

 equipment for its journey and for its start in life; it requires a means of dispersal 

 and protection against attacks from animals so long as it remains attached to the 

 parent-plant, it requires also protection against unfavourable climatic conditions. 

 These various equipments are provided by peculiar changes in the integument, 

 carpels, and receptacle, changes which are initiated at fertilization. 



