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THE AMERICAN NATURALIST [Vol. XLIX 



and Osawa (4) have proved (and as I can confirm), embryos 

 are formed from the tissue of the nucellus adjacent to the em- 

 bryo-sac. I have also shown (1), as Strasburger suspected, that 

 a similar mode of formation prevails in certain varieties of Man- 

 gifera indica. In ¥ 1 hybrids between certain Citrus species (8), 

 these adventive embryos do not show segregation; and the ad- 

 ventive embryos of a mango variety give plants nearly constant 

 to that variety. Hence segregation had not taken place when 

 the cells surrounding the megaspore-mother-cell were formed. 1 

 The same conclusion follows on the work of Ostenfeld (5) and 

 Rosenberg (6) with certain Hieracia. 



John Belling 



REFERENCES 



1. Belling, J. Report of Florida Agricultural Experiment Station for 1908. 



Pp. cx-cxxv, Plates VII-X, 1909. 



2. Belling, J. The Mode of Inheritance of Semi-sterility in Certain Hybrid 



Plants. Zeitschrift fur induktive Abstammungs- und Vererbungslehre, 

 Bd. XII, S. 303-342, 1914. 



3. Geerts, J. M. Beitrage zur Kenntnis der Cytologic und der partiellen 



Sterilitat von Oenothera Lamarckiana. Recueil des Trav. Bot. Neerl., 

 Vol. 5, pp. 93 ff., 1909. 



4. Osawa, I. Cytological and Experimental Studies in Citrus. Jour. Coll. 



Agr. Imp. Univ. Tokyo, Vol. 4, No. 2, pp. 83-116, 1912. 



5. Ostenfeld, C. H. Further Studies on the Apogamy and Hybridization 



of the Hieracia. Zeitsch. ind. Abst. u. Vererbungslehre, Bd. Ill, S. 

 241-285, 1910. 



6. Rosenberg, O. Cytological Studies on the Apogamy in Hieracium. Bot. 



Tidskrift, Vol. 28, 1907. 



7. Strasburger, E. Ueber Polyembryonie. Jenaische Zeitschr. f. Naturwiss., 



Bd. 12, S. 647, 1878. 



8. Swingle, W. T. New Types of Citrus Fruits. Proc. Florida State 



Horticultural Soe. for 1910, pp. 36-42. Plates I-VIII, 1910. 



9. De Vries, H. Gruppenweise Artbildung, 1913. 



i Somatic segregation is not the only available hypothesis in the cases of 

 the double Matthiola and Petunia. For the double stock may have one half 



the pollination of Mirabilis jalapa, in Ber. Beutsch. Bot. Ges., Bd. 18, S. 



