1912] PFEIFFER—LEITNERIA 203 
Fic. 4.—Portion of nucellus of ovule on Jan. 21, showing the single sporoge- 
nous cell and two parietal cells; X 550. 
Fic. 5.—Portion of nucellus four weeks later, showing the periclinal divi- 
sion of some of the epidermal cells, the further development of parietal tissue, 
and the megaspore mother cell in synapsis; 600. 
Fic. 6.—Two-nucleate female gametophyte, with three abortive mega- 
spores immediately above it; 600 
Fic. 7.—The sight ancleite enbiye oe X 600. 
Fic. 8.—Two-celled embryo, awe the longitudinal division of the 
fertilized egg; 600. 
Fic. 8a.—Diagram showing the position of the two- celled embryo seen in 
fig. 8, and the extensive endosperm in the free nuclear condition; X55 
Fic. 9.—Detail of a portion of the outer layer of cells of the embryo seen 
at d in fig. 9a, and the contiguous endosperm cell; X 600. 
Fic. 9a.—Diagram showing position of the young embryo and the absence 
of a slender suspensor; X55. 
Fic. 1o.—Detail of the suspensor region of the embryo seen in diagram 
in fig. 10a; 
Fic. 1oa.—Diagram of an older embryo, showing the developing cotyle- 
dons; X55. 
Fic. 11.—Detail of the cell structure of root end of the embryo and the 
lower portion of the embryo; X 450. 
IG. 12.—Diagram of a mature seed, showing the position of the embryo 
and the extent of the endosperm, perisperm, and seed coats; X12. 5. 
IG. 13.—Diagram showing a young ovule with the position of the nutri- 
tive layer shown in a broken line, and the region shown in detail in fig. 14 
marked out; X 55. 
IG. 14.—Detail of cell structure of region of chalaza marked out in fig. 
13, showing the elongating cells whose further development is seen in figs. 17 
and 18, and the appearance of the nutritive layer (w) when it can first be dis- 
tinguished; 600 
Fic. 15.—Detail of nutritive tissue somewhat later, when the cells seem 
almost free of cytoplasm; X 
Fic. 16.—Detail of putsiive tissue after deposition of reserve material 
has begun; 
Fic. 17 Detail of region seen in fig. 14, after the cells of the nutritive 
layer again lost their reserve material; endosperm cells with starch; X 600. 
Fic. 18.—The region c of fig. 14 when the nutritive tissue is in the condi- 
tion seen in fig. 15. 
Fic. 19.—Diagram showing radiating plates of conductive tissue in the 
chalaza. 
Fic. 20.—Detail of seed coat and outer portion of perisperm. 
