296 
N. Bancroft. 
The anatomical structure of the petiolar tube and thickened 
hypocotyl of Eranthis hiemalis —one of the Ranunculacese—recalls 
that of an Anemarrhena seedling. In the Eranthis seedling figured 
by Miss Sargant (58, PI. II, figs. 7-12), the blades of the cotyledons 
alone are separate, the petioles being united throughout their whole 
length to form a slender cylinder. This cylinder is solid just below 
the blades and above the stem-bud, but hollow between these levels, 
and hollow again over the tuber on which the stem-bud is developed. 
Three bundles from each cotyledonary blade enter the cylinder, but 
the two lateral traces from each blade rapidly unite with their own 
midrib, so that the petiolar cylinder contains two bundles each 
representing a separate cotyledon. The section passing through 
the stem-hud shows each bundle dividing into two, and finally there 
are formed in the hypocotyl four bundles of stem-type, arranged 
more or less in pairs. As these bundles become more widely 
separated with the increasing girth of the hypocotyl, three, and 
ultimately four xylem groups are formed, corresponding to each 
pair of phloem groups. As the hypocotyl narrows again towards its 
base, the xylem collects into four masses, and the four phloem groups 
fuse in pairs. A diarch root-stele is formed by the disappearance 
of two of the protoxylem groups. 
In spite of the differences in detail, the resemblances between 
Anemarrhena and Eranthis are sufficiently clear to suggest that 
each may be referred to the same dicotyledonous plan. 
Zygadenus elegans, a species belonging to the same family as 
Anemarrhena —Liliacese—has seedlings exhibiting unilateral vascular 
symmetry, with one cotyledonary bundle. This type may be con¬ 
nected with the Anemarrhena type, however, by intermediate forms; 
and Miss Sargant finds that seedlings from other monocotyledonous 
families may be derived from a Liliaceous type, or shown to be 
similarly bisymmetrical. 
In these bisymmetrical cases, fusion of the two original coty¬ 
ledons may be supposed to have taken place by both margins, as 
clearly indicated in the case of Eranthis and other Dicotyledons, 
where a cotyledonary tube is formed. Miss Sargant further states 
that monocotyly may arise by fusion of the cotyledonary petioles by 
one margin only. She quotes the cases of Ranunculus Ficaria 1 and 
Anemone apennina , 2 conceiving these to he well-proved cases of the 
1 Cf. the view of Hegelmaier (29) and of Schmid (63), that monocotyly in 
this species is due to suppression of a cotyledon. Compton (11, p. 802) thinks 
that “ on the whole the tendency of the evidence seems to be in favour of the 
view that the seed-leaf of R. Ficaria represents a single cotyledon.” 
2 Compton (11, p. 802) thinks there is some doubt about this species. 
