tii THE STRUCTURE OF ECONOMIC PLANTS 



parthenogenetic development of embryos in an ovule in which no 

 reduction division of the megaspore mother cell occurred. If fer- 

 tilization had been effected, there would be triploid embryos; and 

 tetraploids could be formed in cases where there was also a failure 

 of reduction division in microsporogenesis. Experiments with 

 A. odorum, in which the anthers were removed and the flowers 

 protected against fertilization, indicate that parthenogenetic 

 development, following failure of the reduction division in the 

 formation of the megaspore, does occur. Under such experimental 

 conditions, diploid embryos as described above were obtained. 



LITERATURE CITED 



1. Anderson, P. J., "Development and pathogenesis of the onion smut fungus." 



Mass. Agr. Exp. Sta. Tech. Bull. 4, 1911. 

 1. Chauveaud, G., "Passage de la position alterne a la position superposee de 



I'appareil conducteur, avec destruction des vaisseaux centripetes primitifs, 



dans le cotyledon de I'Oignon (Allium cepa)." Bull. Museum d'Hist. Nat. 



8: 51-59, 1901. 



3. CooLEY, Grace E., "On the reserve cellulose of the seeds of Liliaceae and of 



some related orders." Boston Soc. Nat. Hist. Mem. j.- 1-19, 1895. 



4. Haberlandt, G., "Zur embryologie von Allium odorum L." Ber. Deut. 



Bat. Gesell. 41: 174-179, 192.3. 



5. Hanstein, J., "Ein noch nicht bekanntes System schlauchformiger Gefasse 



im Parenchym der Blatter und des Stengels vieler Monocotylen vor. Monats- 

 bcrichter der Koniglichen Preufs." Akad. Wiss. Berlin, 705-713, 1859. 



6. Hegelmaier, p., "Zur Kenntniss der Polyembryonie von Allium odorum." 



Bot. Zeit. //.• 133-140, 1897. 



7. Hoffman, C. A., "Developmental morphology of Allium cepa." Bot. Ga^. 



9S: 179-2.99. 1933- 



8. Janczewski, E., "Recherches sur I'accroissement terminal des racines dans 



les phanero games." Ann. Sci. Nat., Bot. Ser. V, 20: 161-101, 1874. 



9. Jones, H. A., and Boswell, V. R., "Time of flower primordia formation in 



the onion (Allium cepa, L.)." Proc. Am. Soc. Hort. Sci. ig: 144-147, 1911. 

 ID. , and Emsweller, S. L., "Development of the flower and macrogame- 



tophyte of Allium cepa." Hilgardia 10: 415-418, 1936. 

 II. Kondo, M., "iJber die in der Landwirtschaft Japans gebrauchten Samen." 



Ber. Ohara Inst, fiir landw. Forsch. i: 405-407, 1919. 

 II. Newcombe, F. C, "The cause and conditions of lysigenous cavity-formation." 



Ann. Bot. 8: 403-411, 1894. 



13. Porter, T. R., "Development of the megagametophyte and embryo of Allium 



mutabile." Bot. Gaz- 98: 317-317, 1936. 



14. Rendle, a. B., "On the vesicular vessels of the onion." Ann. Bot. y 169- 



i77> 1889. 



15. Sachs, J., "Ueber die Keimung des Saamens von Allium cepa." Bot. Zeit. 



21: 57-70, 1863. 



