382 



SIR J. LUBBOCK— PHrXOIirOLOarCAL OBSERVATIONS, 



minent rldgo (J) projectiug into the perisperm. Tlie cotyledons 

 in this stage are plano-convex, applied face to face, orhicular, 

 entire, green, with distinct petioles, 5-nerved, with two lateral, 

 suhopposite branches from the midrib some distance below 

 the apex. The plumnle and radicle are small. The cotyledons 



Fig. 103. 



Fig. 104. 



Fig. 105. 



Con vo/ tut I us Soldanella. %. 



Fig. 103. Embryo, X 2. Fig^l04. Section of gieed after removal of the dorsal 

 surface, embryo, and perisperm, X 2. Fig. 105. Side view of ditto, X 2. 



gradually increase in size and grow over the process in which 

 the radicle (a) lies, extending to the apex of tlie seed, doubling 

 over and abutting against the ridge formed by the raphe and 

 chalaza (b), and thus becoming more and more emarginate at the 

 apex. The notch is therefore due to their continuing to grow at 

 the sides after their apex lias rcaclieti this ridge. 



In Ipom<£a purpurea (figs. 106-108), where the seed is con- 



Fig. 100. 



Fig. 107. 



Fig. 108. 



Fig. ICC). EmbrT0,x2. Fig. 107. Section of seed after removal of dorsal 

 surface, embryo, and pcrispenii, x 2. Fig. 108. Side view of ditto, X 2. 



structed generally on tlie same model as in Convolvulus Soldanella, 

 the ridge formed bj the raplie and chalaza (figs. 107 & 108, h), i^ 

 more prominent, and consequently the notch of the cotyledon ia 

 deeper. Lastly, in Ji^omcca dasysperma (figs. 109-111) the pro- 

 jecting ridge of the chalaza is still more developed and grows 

 marly to the process which supports the radicle; the cotyledons 



