6 The Ohio Naturalist. [Vol. IV, No. 1, 



ovulary. The tip of the nucellus emerges slightly between the 

 integuments, the inner of which extends entirely around the 

 ovvile, while the short outer integument does not go be3-ond the 

 middle of the ovule. Just at the base of the stylar canal the outer 

 integument, rising freely from the inner one, bends itself abruptly 

 upward as if to form a stopper to the cavity of the ovulary which 

 at this place is quite large. Guignard (7) says that this upward 

 bending accounts for the shortness of the the outer integument, 

 and also states that the inner integument became thicker where 

 it was not covered by the outer; but the writer saw but little dif- 

 ference in the thickness and if any, the reverse was true. Imme- 

 diatel}^ after fertilization development of the nucellus is very rapid 

 (Fig. 6) so that at that stage of the ovule the embr3'0-sac occu- 

 pies only a verj- small portion of the entire bod3^ Endosperm 

 also begins to develop, spreading upward and backward from the 

 3'oung embryo. When the nucellus has about completed its 

 development the endosperm takes on a rapid growth, destroying 

 the large mass of nucellar tissue. Simultaneous with this growth, 

 the embryo also develops with rapidit3', evidenth' being well 

 nourished b3' the large endosperm cells (Fig. 8). This growth 

 continues until the endosperm entireh' replaces the nucellar 

 tissue, leaving only a vestige of the latter surrounding it (Figs. 

 9-11). 



The 3'oung embr3'0, protected b3' the scutellum, lies on the 

 ventral side of the grain, somewhat above the base of the endro- 

 sperm and outside of it, except for a ver3- thin layer one or two 

 cells in thickness. It is shielded on the outside 133- the remaining 

 nucellar tissue and the carpel wall (Figs. 9-10). 



In Figure 11 is .shown a nearl3' mature grain cut in longitudinal 

 section transverse to the ear. The remains of the nucellus is verv 

 thin or entirely absent. A little above the base of the grain is 

 the 3'oung embr3'0, showing the plumule and the .scutellum, 

 below which the large suspensor extends with its end surrounded 

 with elongated endosperm cells. Across the upper end of the 

 grain is shown a strip of endosperm with larger and quite irregu- 

 lar cells. There are sixt3' or more cells acro.ss the entire width, 

 the cells being comparatively minute in comparison to tlie size of 

 the grain and not large as is usually figured in the text-books. 



HIBLIOGRAl'HY. 



1. Bati-;son, W. Mendel '.s Principles of Heredity. Pp. 40-103. 1902. 



2. CoRRKNS, C. Unterscuhungen ueber die Xenien lici Zea nia3-s. Ber. 



d. dent. P>ot. Gesellsch. 17:410-417. i^>99- 



3. Dk Vriks, Hur.o. Sur la Fecondation hybride de I'alhunKn. Comptes 



rendns .\cad. des So. 4 Dec. 1S99. 

 4. . Sur la Fecondation hybride de I'endosperin dans le 



Mais. Revue gen. de Bot. 15 April 1900. 

 5. P'OCKE, W. O. Die Pflanzen Mischlinge. p. 511. 1S81. 



