286 BOTANICAL GAZETTE [APRIL 
caulon. In other plants mature undifferentiated embryos have been 
reported within recent years in numerous instances; for example, in 
Aigenetia (KUSANO I0) and Peperomia (CAMPBELL 2); also Gunnera 
(MopILEwskKI 12) has no suspensor, and Piper (JoHNSON 8) but a 
slight one. But undoubtedly the nearest parallels to the embryo sac 
of Eriocaulon as yet described are among the Araceae and the Nym- 
phaeaceae. Thus in Arisaema (Gow 7) the mature embryo sac is 
globular and without differentiation of organs; but its first three 
cells are in a row, and its early divisions are less regular. From 
CAMPBELL’s studies of the Araceae (1, 3, 4) it appears that the globu- 
lar form of the embryo is characteristic of that order. But the em- 
bryos figured by him show far more irregularity in their development 
than is the case in Eriocaulon. CampBety regards the absence oF 
slight development of the suspensor (as in Aglaonema 1 and Spathi- 
carpa 3) as correlated with the complete investment of the embryo — 
by endosperm tissue. In all the Araceae examined the endosperm 
was found to be septate from the beginning. The same is the case 
in Gunnera. It will be seen, however, that this explanation will not 
apply to the lack of a suspensor in Eriocaulon, since divisions of the 
embryo up to the octant stage precede tissue formation in the endo- 
sperm, and even for some time afterward the walls of the endosperm 
are too weak to exert much pressure. Pistia, another aroid, was 
investigated by HEGELMAIER (8) in 1874, and its enibryo as described 
by him is in its early history practically identical with that of Erio- 
caulon. It shows the same regularity of form and sequence UP to 
the cutting off of the “dermatogen-like outer layer,” and for some, 
time thereafter, except that for a time in individual ‘cells of this 
layer periclinal divisions now and then occur, a phenomenon I have — 
not observed in Eriocaulon. In the ripening seed of Pistia the 
globular embryo becomes indented, and root tip and cotyledon are 
developed. 
Somewhat similar embryos occur in Castalia odorata and Nym- 
phaea advena (CooK §) and in Nelumbo (York 16). These af 
described as passing through quadrant and octant stages, less - 
than those of Eriocaulon and Pistia. The case of Nymphaea 8 a 
particularly interesting. Though the extent of the dermatogen 
not stated, from the figures it appears to invest the embryo completely; 
