PINE REPRODUCTIVE ORGANS 257 



as the apex of the endosperm, where it widens out into 

 a large sac. 



Observe near the apex of the endosperm, and 

 embedded in it, one or more large vacuolated proto- 

 plasmic bodies ; these are the egg-cells, or ova : from 

 the apex of each may be traced a narrow neck or 

 channel, inclosed by smaller cells than those of the 

 surrounding endosperm. The neck and central cell 

 together form the corpusculum, that is, the arche- 

 gonium. The endosperm corresponds to the prothallus 

 of the Fern, while the corpuscula are equivalent to the 

 archegonia. 



III. Remove ovules from cones of the second year, 

 taken and preserved in alcohol about August 1. Dis- 

 sect off from them the now hardened integument or 

 seed-coat : note within this the delicate remnant of 

 the nucellus, which covers the mass of endosperm. 

 Soak the latter in water, and dissect from it with 

 needles the numerous embryos, which lie in the 

 central cavity of the endosperm : treat them with 

 potash, and mount in dilute glycerine. Examine with 

 a low power, and observe 



1. The suspensors, coiled filaments consisting of 

 'numerous transparent thin- walled cells. At the ends 



of the suspensors are boroe 



2. The embryos : they are more or less elongated, 

 almost cylindrical bodies: in some cases (only one as a 

 rule in each seed) they may have already formed 



a. An apical cone, which terminates the free, 

 anterior end of the embryo; this being surrounded 

 by- 



I. A whorl of cotyledons of variable number. 



s 



