14 



INTRODUCTION TO EMBRYOLOGY OF ANGIOSPERMS 



tazetta) can give rise to the embryo sac. In Lilium and Tulipa the 

 formation of daughter cells was found to be entirely omitted so that 

 the embryo sac arises directly from the megaspore mother cell. 

 . The Embryo. Hanstein (1870) was the first to follow the sequence 

 of early cell divisions in the development of the embryo. He gave a 

 detailed description of the embryogeny in Capsella and Alisma 



Fig. 12. Stages in development of embryo of Alisma plantago (v = suspensor; 

 h = hypophysis; w = radicle; p = plumule; c = cotyledon; b = first leaf; the 

 shaded portions represent the derma togen). (After Hanstein, 1870; reproduced 

 rom Sachs, 187 4-) 



(Figs. 11, 12). Famintzin confirmed these observations in 1879, and 

 in the same year Treub described the embryos of several orchids 

 with their remarkable suspensor haustoria. Two years later Guig- 

 nard (1881) gave a full account of the extremely massive suspensors 

 of the Leguminosae. 



At about this time, detailed investigations were also made on the 

 peculiar phenomenon of polyembryony. Long ago Leeuwenhoek 

 (1719) had noted the occurrence of more than one embryo in certain 



