CONIPBRALBS 



103 



four cells of the embryonal 

 tier, eacli of ■which begins the 

 development of an embryo. 



In many Conifers the ap- 

 pearance of embryonal tubes 

 is a prominent feature. These 

 tubular processes are devel- 

 oped from basal cells of the 

 embryo, and seem to serve 

 as additional absorbing or- 

 gans (Fig. 78, B). They are 

 found investing the suspensor 

 and the base of the embryo, 

 and are sometimes exceeding- 

 ly numerous. 



3. Development of Em- 

 bryo. — Concerning the devel- 

 opment of the embryo proper 

 our knowledge is meager. 

 In every case, with the excep- 

 tions noted below, it is devel- 

 oped from the lowest cell or 

 tier of cells at the base of the 

 oospore, the tier which is car- 

 ried down by the suspensor. 

 As has been stated, the cells 

 of this embryonal plate, usu- 

 ally four or six in number, 

 may together organize a sin- 

 gle"^ embryo, or in Abieteae 

 each one is more apt to de- 

 velop separately. We ob- 

 served one case in Pinus La- 

 ricio which may serve to 

 indicate the possibilities in 

 connection with the devel- 



FiG. 78. — Pinus Zaricio, showing youns; 

 emtryo ; A,tvro young embryos with long 

 suspensors ; J?, an older embryo, showing 

 three embryonal tubes. 

 8 



