PINUS. REPRODUCTIVE ORGANS. 159 



to be found lying on the apex of the nucellus ; and 

 that from the larger cell of each of them arises a 

 Pollen-tube, which traverses the tissue of the nucellus, 

 as far 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 Oospheres. 

 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 

 archegonium). 



C. Remove ovules from cones of the second year taken 

 and preserved in alcohol about August 1. Dissect off 

 from them the now hardened Integument (Testa). 

 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 Embryos 

 (numerous), 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 borne 



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, an- 

 terior end of the embryo ; this being surrounded by 



b. A whorl of Cotyledons of variable number. 



