52 Sorgant . — Theory of the Origin of Monocofy/edons 
There are points in this structure which recall that of 
Thrinax. The most important feature is. I think, the presence 
of two equivalent bundles in the cotyledon. 
The twenty-five species of Monocotyledons — exclusive of the 
Liliaceae — which have just been described, fall naturally into 
two groups. The anatomy of seedlings belonging to the 
Amaryllidaceae, Iridaceae, and Aroideae seems to be derived 
from a Liliaceous type. That of the Palmae and Scitamineae 
is distinct in character, but the dual symmetry of the cotyledon 
is not less marked. The evidence from these two families, so 
far as it goes, is perfectly consistent with the hypothesis of 
a double cotyledonary member, and even gives it some 
support. 
Part II. Ranunculaceae. 
No detailed comparative study of this family has been 
attempted. The seedling which first attracted my attention 
was that of Eranthis hiemalis as described by M. Sterckx 
(38), to whose excellent monograph I have referred elsewhere. 
Since repeating his observations on the vascular system of 
Eranthis with particular reference to the tuberous hypocotyl, 
I have examined the seedlings of two other species possessing 
cotyledonary tubes : Delphinium sp. (possibly D. nudicaule ) 
and Anemone coronaria , and also two species with distinct 
epigaeic cotyledons, Delphinium Requienii and Nigella dama - 
scena. 
M. Sterckx has shown that the single cotyledonary member 
of Ranunculus Ficaria is in all probability formed by the 
union of two cotyledons by one margin only. I have repeated 
his observations on the external features of this seedling, 
and have made a careful study of the course of the vascular 
bundles in the cotyledon, hypocotyl, and primary root. For 
comparison two other species which show apparent lateral 
insertion of the cotyledons were chosen, Ranunculus Chius 
with epigaeic, and Anemone nemorosa with hypogaeic 
cotyledons. 
