FLOWERS OF IMP A TIENS FULVA 183 



Plate LVI 



Fig. 16. Ovule showing single archesporial cell and beginning of inner integument. 

 X300. 

 Fig. 17. Megaspore daughter cells. 



Fig. 18, Four megaspores, X850. 



Fig. 19. Embryo-sac two nuclei. Two degenerating megaspores. XIOOO. 



Fig. 20. Embr>'o-sac with four nuclei. X 1000. 



Fig. 21. Embrj^o-sac with egg and two polar nuclei; one synergid cut ofif above and 

 three antipodals below. XIOOO. 



Fig. 22. Embry-o-sac with six nuclei. XIOOO. 



Fig. 23. Embryo-sac with two polar and egg nuclei; two synergids cut off above. 

 X 1000. 



Fig. 24. Origin of the second integument. 



Fig. 25. Embryo-sac showing two polar nuclei; branched pollen tube with male 

 nuclei and remains of tube nucleus. 



Fig. 26. Embryo-sac with egg and polars; branched pollen tube with male nuclei 

 and remains of tube nucleus. 



Fig. 27. First division of fertilized egg; endosperm nuclei. X290. 



Fig. 28. Three cells of a four-celled embryo; beginning of segmentation of endosperm ; 

 the jacket layer of the integument. X400. 



Fig. 29. Embryo showing two-celled suspensor, and dermatogen, and the first cells 

 of the endosperm. X300. 



Fig. 30. Embryo with five-celled suspensor; the first cells of the endosperm degen- 

 erating. X300. 



Fig. 31. Embryo showing division of the basal suspensor cells. X450. 



Fig. 32. Embryo with the cotyledons arising, mature suspensor and layers of en- 

 dosperm cells. X75. 



Plate LVII 



Fig. 33. Longitudinal section of a cleistogamous flower showing the forcing off of 

 the perianth cap, the pollen tubes and the stylar canals. X30. 



Fig. 34. Cross section of ovary of chasmogamous flower showing the enlarged cells 

 of hypodermal layer, the smaller cells opposite the septa marking the 

 lines of dehiscence and the beginning of degeneration of the septa. X 124. 



FiG. 35. Cross section of ovary of chasmogamous flower with seed near maturity 

 showing degeneration of inner layers of ovary wall, the enlargement of 

 epidermal and hypodermal layers of ovary wall, and development of 

 seed coats. X50. 



F.G. 36. Longitudinal section of ovule with embryo showing degeneration of middle 

 layers of integument. 



