1922] ; JURICA—UMBELLIFERAE 307 
Fic. 11.—Longitudinal section of ovary of Sium cicutaefolium, showing 
the two ou beginning development in one of ovary cavities. 
Fic. 12.—Section of E. yuccifolium ovary, showing the two ovules in 
single ovary cavity; only lower ovule generally develops. 
1G. 13.—Longitudinal section of ovary of E. yuccifolium, showing an 
unusual condition, the developing of two ovules in single ovary cavity. 
FI ves —Anatropous ovule of E. yuccifolium 
Fic. 15.—Nucellus of Sium seeagec iouing two cells, result of 
first division of megaspore mother c 
Fic. 16.—Mature embryo sac of S. cicutaefolium, showing breaking down 
of sinaling. egg, one of synergids, fusion nucleus, three antipodals, and nutritive 
apparatus. 
Fics. 17-30.—Eryngium yuccifolium. 
Fic. 17.—Ovule showing single integument and nucellus. 
Fic. 18.—Nucellus showing megaspore mother cell in synapsis. 
Fic. 19.—Nucellus showing four megaspores 
Fic. 20.—Single megaspore from which entre sac will develop; nucellus 
beginning to break down. 
Fic. 21.—Two-nucleate embryo sac, showing nutritive apparatus. 
Fics. 22, 23.—Two and four-nucleate embryo sac, showing nuclear 
divisions. 
Fic. 24.—Lower end of embryo sac, showing one of polar nuclei, three 
stip, and nutritive apparatus. 
G. 25.—Mature embryo sac, showing remains of broken down nucellus, 
egg, re ie fusion nucleus, remains of antipodals, and nutritive apparatus. 
Fic. 26.—Embryo sac in cross-section, showing endosperm formation b 
free nuclei. 
Fic. 27.—Free nuclei of endosperm of embryo sac in longitudinal section. 
Fics. 28-30.—Embryo and suspensor. 
