1901] Leavitt, — Embryology of New England Orchids. 203 
push the embryo down into the nourishing endosperm, or to draw 
nutritives from the nucellus. The suspensor finally perishes. Fig. 
2 illustrates the usual differentiation of the new monocotyledonous 
individual into two regions, suspensor and * embryo proper"; though 
in this species (Zémnocharis emarginata) the end-cell of the feeding- 
organ is uncommonly large. That the simplification of the germ, 
characteristic of the orchid family, should in the above named 
species include the omission of so radical a step in early develop- 
ment as the differentiation of the embryo into temporary and 
permanent regions, is a noteworthy feature of the embryogeny. 
Polyembryony. Occasional doubling of the embryo has been noted 
heretofore in a small number of orchid species, including representa- 
tives of Cypripedium, Orchis, and Gymnadenia. I find twin embryos 
in both the present species of Goodyera. Apparently here as in 
certain ascertained cases both embryos originate in the same sac, 
though I have seen examples only in the ripe seeds. However, both 
are often plainly invested by a common membrane, probably the 
remains of the sac with contiguous cells. Strasburger supposed that 
in the double-embryoed species there are occasionally two egg-cells 
in the same sac. 
The percentage of polyembryonous seeds must be very small, 
though I have been able to find from one to three or four instances 
in each slide of seed examined. The close appression of the 
embryos — one being smaller than the other and lying more or less 
in a concavity of the larger one — makes it rather hard to dis- 
tinguish the twin-seeds from the rest. It should be mentioned that 
supposed hybrid seed (from pollen of G. Zesse/ata upon G. pubescens) 
gave a much larger proportion of twins than seed of either parent. 
APLECTRUM HIEMALE. Double embryos (Fig. 7) occur about as 
frequently as in the Goodvera species. Both members of the pair 
have the remains of suspensors (s) This fact is important as 
indicating similarity of origin, and precluding the idea that doubling 
results from fragmentation of an original single embryogenic mass. 
CORALLORHIZA MULTIFLORA. As seen in the nearly ripened seed 
(Fig. 8) the suspensor (s) comprises two very long cells. It is 
plainly an organ of absorption, for it passes out of the exostome and 
plunges its tip into the tissue of the placenta. 
I have found, after much looking, a single two-embryoed seed. 
The embryos were very closely pressed together, but each had its 
suspensor. 
