166 



INTRODUCTION TO EMBRYOLOGY OF ANGIOSPERMS 



Upcott (1936) in several species of Tulipa, Eigsti (1939) in Lilium 

 canadense, L. speciosum, L. auratum, Polygonatum commutatum, 

 Convallaria majalis, and Tradescantia reflexa, Johnston (1941) in 

 Tulipa gesneriana, Amaryllis spp., Nicotiana tabacum, Forsythia 

 viridissima, Camellia japonica, and Bryophyllum pinnatum, and 



E 



Fig. 102. Division of generative cell of Lilium regale as seen in pollen tubes grown 

 in culture. A, prophase. B-C, metaphase chromosomes advancing to equatorial 

 plate. D-F, metaphase. G, three chromosomes at metaphase. II, two chromo- 

 somes at early anaphase. /, late anaphase showing cell-plate formation. J, two 

 male gametes; cell plate completed. {After Cooper, 1936.) 



Beatty (1943) in Eschscholtzia calif ornica (Fig. 103) have emphasized 

 that spindle fibers are present and perform the same functions as in 

 normal mitosis. 



Coming finally to the mode of cytokinesis, Raghavan ct al. (1939) 

 in Impaliens, Banerji and Gangulee (1937) in Eichhomia, and several 

 other authors have reported that the division of the generative cell 

 occurs by a constriction. Eigsti (1940) also states that cell plates 



