1914] FARRELL—CYRTANTHUS SANGUINEUS 431 
Embryo 
The literature of the embryos of monocotyledons is extensive 
but not satisfactory. The ‘sheath’ was recognized, of course, 
early in the history of the study, and was presumed to be a single 
cotyledon, giving the name to the whole class. Besides the presence 
of the single cotyledon, early investigators were so impressed with 
the large amount of endosperm or “albumen,” as they called it, 
occurring outside the embryos in such seeds, that they also called 
them ‘‘albuminous.” As to the origin and nature of the cotyle- 
donary sheath, various opinions are expressed, which fact perhaps 
demonstrates that there are various modes of origin. The earliest 
writers, HANSTEIN (3) and FAmiIntzin (4), described the embryo 
of Alisma Plantago, in which the cotyledon is terminal in origin. 
HEGELMAIER (5) describes it in some cases as arising from a cell 
near the tip, and being pushed into the terminal position by later 
development. SHAFFNER (6) says that in Sagittaria the cotyledon 
arises from the terminal cell of the proembryo. CAMPBELL (7) 
finds the same condition in Naias; the same author in his study of 
Lilaea (8) says that the sheath is not at first an enveloping organ, 
but that it becomes such by the lateral growth of its margins; and 
the same facts are repeated for the Araceae (9). WITTMACK (10) 
in his monograph on the Bromeliaceae has a drawing of a longi- 
tudinal section of the embryo of Guzmannia tricolor, taken through 
the center in such a way as to show the elongated side of the sheath 
on one side and the shorter side on the other. He calls the long 
side the “‘scutellum” and the short side the “cotyledon.” There 
is nothing in his figure to show that scutellum and cotyledon are 
not one and the same structure, and yet it would seem that so 
reliable an investigator must have had some reason for applying 
the two terms in this way. BILLINGs (11) says that the cotyledon 
is terminal in origin, that the middle segment of the three-celled 
proembryo gives rise to all the other organs, and that before the 
stem tip is differentiated, the cells surrounding the area where it is 
to arise grow up into a ridge of tissue, which in the mature embryo 
incloses the growing point completely. Here the author seems to 
imply (1) that the sheath does not completely inclose the growing 
point in its inception, and (2) that the sheath is not the cotyledon, 
in the latter respect agreeing-with W1TTMACK. 
