SEED-BEARING PLANTS 



399 



the megaspores of Cycads never leave the sporangium. The 

 developing female gametophyte is nourished entirely as 



Fig. 296. — Ovule of ilacrozamia Moorei, A, external view; B, portion 

 of integument removed, showing egg-shaped gametophyte. The dark 

 strip on the upper left-hand portion of the latter^is where a piece of the 

 now membranous nucellus was peeled off; C, gametophyte, entire, with 

 nucellar cap at the upper end; D, longitudinal section; E, end view, with 

 part of the integument removed, disclosing the tiny crater-like pollen- 

 chambers, at the bottom of which the necks of the archegonia open. (Cf . 

 Fig. 297.) .\bout natural size. 



a parasite, by the tissue of the nucellus- The latter 

 becomes almost entirely consumed, so that when a longi- 



