2l8 
MORPHOLOGY 
deep into the endosperm by the rapidly and extensively elongating 
suspensor. In the organization of the embryo two cotyledons appear, 
as in all the preceding groups of gymnosperms. Torreya is peculiar 
in the irregular growth of its endosperm (female gametophyte), which 
484 
FIGS. 482-484. Embryo of Torreya: 482, the stage of four free nuclei; 483, the 
completed proetnbryo (filling the egg), the cells approximately in three tiers; 484, upper- 
most tier of proembryo elongating to form suspensor. After COULTER and LAND. 
encroaches upon the surrounding nucellar tissue in such a jagged way 
as to give the appearance in the seed called rumination, which may 
be seen also in sections of nutmegs. 
Conclusions. The Taxaceae have not been traced with certainty 
below the middle of theMesozoic, so that it seems to be a comparatively 
modern group among gymnosperms. It has made a decided advance 
