704 The American Naturalist. [August, : 
marked off from the latter by distinct cell walls. They persist for 
some time after fecundation, and as in Helianthus, send out vermiform 
protoplasmic extensions that assist in tearing down the adjacent tis- 
sues. Shortly prior to fecundation the tissue just outside the endo- 
dermis begins to degenerate by losing its protoplasmic contents. With 
the development of the endosperm and the growth of the embryo, this 
absorption of the tissue of the ovule proceeds to such an extent that, 
as Hegelmaier* notes in Helianthus, the endodermis, with its contents, 
can be removed with ease. While this is going on the one-layered 
endodermis has become many layered except at its micropylar and 
antipodal ends (fig. 15). Its cells become rich in protoplasm: at the 
expense of the surrounding tissue now rapidly becoming depauperate. 
The suggestion of Hegelmaier that this condition in Helianthus may 
be due to cultivation, ete., is of Jittle value, since the same condition 
occurs in Grindelia and also in uncultivated Helianthus. Later, as 
the seed matures, the endodermis as such disappears, being represented 
only as a thin, compressed coat of the embryo. 
It is thus seen that the development of Grindelia agrees closely 
with that of Senecio described by Warming‘ and Vesque; though the 
latter of course was considerably in error. Conyza, described by 
Guignard’ has a similar development, but the antipodal cells are more 
numerous than in Grindelia. Helianthus, studied by Hofmeister,’ and 
later by Hegelmaier,’ agrees very closely with Grindelia. As in 
Helianthus the endodermis is strongly developed, in marked contrast 
to Ageratum where it is scarcely differentiated. Hegelmaier observes 
in the mature embryo-sac of Senecio five nuclei: the two synergide, 
the odsphere, and two secondary nuclei of the embryo-sac. The same 
is seen in Grindelia. 
In a short notice of this kind, for the most part merely confirma- 
tory of similar studies of others, it seems hardly worth the while to 
Loc. cit. 
*De l’Ovule. Ann. Sc. Nat. 6, Sér. v. 1878, p. 176. 
5 Développement du sac embryonnaire des Phanérogames, Ann. Sc. Nat. 6 sér-, vi, 
1878, p. 237. Nouvelles recherches sur le développement du sac embryonnaire des 
végétaux phanérogames angiospermes. Ann, Sc. Nat. 6 sér., viii, 1879, p. 261. 
6Recherches sur le sac embryonnaire des Phanérogames. angiospermes. Ann. Sc, 
Nat. 6 sèr.. xiii, 1882, p. 136. : 
TEntstehung des Embryo. Leipzig, 1849, 
euere Beobachtungen über Embryobildung der Phanerégamen. Pringsheim’s 
Jahrbiicher, i, 1858, p. 82. 
Loc. cit. 
