Erythronium americanum . 541 
embryos 1 should be fertilized by the two generative nuclei of 
the pollen-tube. The conditions in Erythronium also lend 
strength to this opinion. From lack of material I have not 
been able to reinvestigate the facts in Mimosa . 
Iris versicolor was examined in the hope of finding poly- 
embryony, but it was found to possess normal embryos. As 
Iris sibirica was not available, it was not possible to compare 
it with Erythronium . 
The polyembryony of Erythronium americanum is also of 
interest, in that it is exactly homologous with the polyembryony 
which is so commonly found among the Gymnosperms. The 
resemblance extends even to the ultimate persistence of only 
one of the multiple embryos. 
1 Op. cit, Plate I, Fig. 31. 
EXPLANATION OF FIGURES IN PLATE XIX. 
Illustrating Mr. Jeffrey’s paper on Polyembryony in Erythronium. 
Fig. 1. Embryo -sac just after fertilization has taken place. In the oospore the 
male and female nuclei are seen in process of union. The synergids have dis- 
appeared. x 180. 
Fig. 2. A later stage. The embryonic mass consists of two cells, in the upper 
of which a mitosis is just taking place. X 250. 
Fig. 3. The embryogenic mass has increased in size, x 250. 
Fig. 4. The embryogenic mass has grown still larger, x 250. 
Fig. 5. The still more enlarged embryogenic mass is beginning to give rise to 
embryos, x 250. 
Fig. 6. Four embryos are seen projecting from the embryogenic mass, x 180. 
