462 Mottier . — The Embryology of some Anomalous Dicotyledons. 
EXPLANATION OF FIGURES IN PLATES XXVI AND XXVII. 
Illustrating Professor Mottier’s paper on the Embryology of Anomalous Dicotyledons. 
Unless otherwise stated, all figures were drawn from carefully prepared microtome sections with 
the aid of the camera lucida. 
Figs. 1-8. Actea alba. 
Figs. 1 and 2. Longitudinal sections of young embryos, the cells of the suspensor contain 
starch, x 425. 
Fig. 3. A transverse section through the middle of an embryo in the stage of development of 
Fig. 1. x 425. 
Fig. 4. Median longitudinal section. The embryo is becoming pear-shaped. The suspensor is 
short, its cells contain starch, x 425. 
Fig. 5. A typical pear-shaped embryo just prior to the appearance of the cotyledonary primor- 
dium. x 425. 
Fig. 6. View of an embryo after the appearance of the cotyledonary primordium, which is 
a thick crescentic ridge formed at the margin of the truncated distal end. The opening of the crescent 
faces the observer. This opening, or primary sinus, is an indentation at one side of the embryo 
extending towards the centre, but becoming shallower at that point. This figure was constructed 
from the series of cross-sections shown in Fig. 17. 
Fig. 7. Longitudinal section of an embryo from a nearly mature seed, at right angles to the 
plane of the cotyledons. Only one cell of the suspensor is omitted from the drawing. The plerome 
strands in hypocotyl and cotyledons are being differentiated, x 250. 
Fig. 8. View of an embryo from a mature seed. The cotyledonary sinuses are of unequal depth, 
the primary sinus which is nearest the observer being deeper. Constructed in the same manner as 
Fig. 6. 
Figs. 9, 10. Sanguinaria canadensis. 
Fig. 9. Median longitudinal section through young cylindrical embryo with very short 
suspensor. x 425. 
Fig. 10. Transverse section through a similar embryo, x 425. 
Fig. 11. Delphinium tricorne. Transverse section through broad end of pear-shaped embryo 
before the appearance of the cotyledonary primordium. Tissues undifferentiated, x 300. 
Figs. 12, 13. Aquilegia canadensis. 
Fig. 12. Longitudinal median section through young embryo, x 425. 
Fig. 13. View of embryo from mature seed. The middle part of each cotyledon is omitted. 
Constructed in the same manner as Figs. 6 and 8. 
Figs. 14-19. Actea alba . 
Fig. 14. Transverse section through the base of the cotyledonary primordium, showing primary 
sinus ; st. apex of stem ; pi. plerome strands, x 300. 
Fig. 15. Section similar to Fig. 14, but from an embryo showing no anomaly. The two sinuses 
of the cotyledons were formed simultaneously. This embryo was obliquely symmetrical, x 300. 
Fig. 16. Similar to Fig. 15, but from a symmetrical embryo. 
Fig. 17. A series of transverse sections of an embryo shown in outline, at the time of the 
appearance of the cotyledonary primordium. Sections were cut 7’5 microns in thickness. a-k t 
alternate sections ; /-/, successive sections, x 300. 
Fig. 18, a-h. A series of transverse sections beginning just below the cotyledons. This embryo 
showed no perceptible anomaly; one cotyledon, however, was longer than the other, x 125. 
Fig. 19, a-h. Similar series, but of an older embryo. The anomalous character is typical and 
the most pronounced at this stage for this species, x 180. 
Figs. 20-25. Sanguinaria canadensis. 
Fig. 20. Outline of a median longitudinal section of a pear-shaped embryo. The slightly 
depressed centre is an indication of the beginning of the cotyledonary primordium. x 180. 
