456 Mottier.— The Embryology of some Anomalous Dicotyledons . 
subsequent growth the pear-shaped form is assumed, and the beginning of 
the cotyledons is soon manifested (Fig. 33, a-d , representing four consecutive 
sections only of the embryo). A comparison of this figure with figures 
29 and 30 will show the similarity in the origin of the cotyledons with 
that in Delphinium. It is evident that, in this case, the primordium 
was kidney or bean-shaped, but as it bifurcates soon after being laid 
down, the anomalous character can be said to exist only as a mere trace. 
This is made clear in Fig. 34, a-f. In this embryo the cotyledonary 
primordia seem to have arisen separately, and not as one piece, the two 
involving, however, nearly the whole end of the embryo. In d, Fig. 34, 
the base of one of the young cotyledons is more massive than the other. 
In fact, in all species of the two families examined, it not infrequently 
happens that one cotyledon is larger than the other, being sometimes 
longer or thicker (see also Fig. 18). Fig. 35, a-g, refers to an embryo 
of a mature seed. This series is not consecutive throughout, one or more 
sections being omitted between b and c, d and *?, and f and g. The 
base of each cotyledon is almost cylindrical, a feature in which Aquilegia 
differs from the other genera mentioned. The nature of the embryo 
in the mature seed is shown in Fig. 13. This figure was constructed 
from a series of cross-sections as mentioned for the preceding species, 
with the exception that the middle portion of each cotyledon has been 
omitted in order to show that, while the cotyledons are somewhat 
cylindric at the base (e, Fig. 35), they soon become concave within, and 
consequently crescentic in transverse section. No indication of a plumule 
was observed in the embryo of the ripe seed. 
Syndesmon thalictroides. 
Measured by the standard of endosperm-formation, the development 
of the embryo in Syndesmon is relatively slow ; for, in a large percentage 
of the preparations made from the ripe seed, the cotyledons had just 
put in an appearance. In some cases no indication of these were to 
be seen, while in others the cotyledons had attained a length equal 
to about one-third of the length of the entire embryo. The origin of 
the cotyledons seems to be typically dicotyledonous, even more so 
than in Aquilegia , so that it was not considered necessary to give 
illustrations. In only one case was the slightest indication of an anomaly 
observed. The first appearance of the cotyledonary primordia, it may 
be added, is almost identical with that in Aquilegia in which no anomaly 
was observed, and this fact is probably due more to a similarity in habit 
than to genetic relationship. The suspensor of the embryo seems to 
be a little more massive than in the species hitherto mentioned, the whole 
embryo, however, resembling that of Aquilegia. 
