142 MORPHOLOGY OP ANGIOSPBRMS 



56. Frye, T. C. Development of the Pollen in some Asclepiadaceae. 



Bot. Gazette 32: 325-331. pi. 13. 1901. 



57. Rosenberg, O. Ueber die Polleubildung von Zostera. Meddel. 



Stockholms Hogsk. Bot. Inst. pp. 21. 1901. 



58. Gager, C. S. The Development of the Pollinium and Sperm Cells 



in Asclepias Cornuti. Annals of Botany 16: 123-148. pi. 7. 

 1902. 



59. Guignard, L. La double fecondation chez les Solanees. Jour. 



Botanique 16: 145-167. figs. 45. 1902. 



60. Cheauveaud, G. L. De la reproduction chez le dompte-venin. 



Diss. Paris. 1902. 



