424 BOTANICAL GAZETTE [December 



Fig. 21. — Diagram of wax model of vascular bundle system of perianth 



and ovary. 



Fig. 22. — Longitudinal section of flower at time of ripe embryo sac; X6o. 

 Fig. 23. — Tangential section of one of thickened pitted cells of ovarian 



wall; X70. 



Fig. 24. — Surface view of young inflorescence showing bracts and two 



young flowers; X20. 



Fig. 25. — Surface view of ripe fruit; X20. 



Fig. 26. — Nearly longitudinal section of young ovule showing tapetal 

 and definitive archesporial cells; X650. 



Fig. 27. — Similar section showing inner and outer integuments, origin 

 of tapetum, and increase in size of megaspore mother cell; X650. 



Fig. 28. — Similar section of ovule at still later stage showing inner integu- 

 ment closed above nucellus to form micropyle; X650. 



Fig. 29. — Longitudinal section of nucellus showing young embryo sac 

 with 2 degenerating megaspores above it; X600. 



Fig. 30. — Similar section at later stage showing embryo sac and 3 degen- 

 erating megaspores; X600. 



Fig. 31. — Similar section of older nucellus showing polarity of 4-nucleate 



embryo sac; X600. 



Fig. $2. — Longitudinal section of embryo sac showing mitosis in division 

 of 4 nuclei like those shown in fig. 31; Xnoo. 



Fig. 33. — Similar section of a mature 7-nucleate embryo sac; X570. 



Fig. 34. — Similar section of micropylar half of mature embryo sac showing 

 typical position of egg apparatus and uninucleolate endosperm nucleus; X57°- 



Fig. 35. — Similar section of embryo sac after pollen tube has entered; X 57°- 



Fig. 36. — Longitudinal section of embryo sac showing first two endosperm 

 cells; X600. 



Fig. 37. — Similar section showing further division of endosperm and 

 antipodals still persistent at base of embryo sac; X600. 



Fig. 38.— Similar section of H. arborescens at slightly later stage than 

 shown in fig. 37; X600. 



Fig. 39. — Similar section of micropylar portion of embryo sac at 3-celled 

 stage of embryo; X500. 



Fig. 40. — Drawing of similar section at later stage showing embryo; X 5°°- 



Fig. 41. — Longitudinal section of micropylar end of nucellus and embryo 

 sac showing character of endosperm around embryo; X650. 



Fig. 42. — Longitudinal section of nearly mature seed showing embryo, 

 endosperm, remains of nucellus, and surrounding wall of ovary with protective 

 cells and still persistent perianth; X60. 



Fig. 43. — Similar section of nearly ripe seed showing embryo, endosperm, 

 and one integument at micropylar end; X125. 



Fig. 44. — Longitudinal section of germinating seed removed from fruit 

 showing absorbent cotyledons still imbedded in endosperm; X60. 



