Davey. — Seedling Anatomy of certain Amentiferae. 587 
Pterocarya rhoifolia (Fig. 18, Vi). This species has a fairly robust 
epigeal seedling with a long hypocotyl. The cotyledons (deeply four- 
lobed as in the other genera) are thin and leaflike. Their petioles possess 
two pairs of lateral strands and a small central one as in Juglans . Near the 
node the neighbouring lateral strands approach and fuse, while the central 
strand becomes divided, its halves merging with the laterals. There thus 
result two large divergent strands which enter the axis at diagonal corners 
as endarch bundles. At this level there is no central protoxylem. The 
first plumular leaf-trace shows slight lignification which dies out at the 
cotyledonary node. The cotyledonary metaxylems become divided, and 
their halves approach the neighbouring cotyledonary and intercotyledonary 
planes, where at lower levels protoxylem is differentiated slightly external 
to the metaxylem. Protoxylem and metaxylem become approximated so 
as to produce flattened secants about the cotyledonary and intercotyle- 
donary poles. At this stage the stele is very large, and the diagonally 
placed phloems form much-extended tangential bands. In the region 
of the collet only centripetal development of the xylem occurs. The root 
is tetrarch and shows a very large pith. A thin-walled endodermis with the 
characteristic radial dot is present in the greater part of the hypocotyl. 
Fortunea chinensis (Fig. 18). This seedling, although smaller than 
that of Pterocarya , resembles it closely in habit and also in anatomical 
structure, except for the fact that the central cotyledonary protoxylem of 
the hypocotyl extends upwards into the minute centra! strand <?f the 
cotyledon. 
Fagales. 
Betulaceae. With the exception of Corylus Avellana the seedlings of 
this family are small and slender, having an elongated hypocotyl and 
epigeal cotyledons. Portions of the cotyledon blades are prolonged down- 
wards as auricles. 
Alnus inc ana y A. glutinosa y and A. cor difolia. These are slender, why 
seedlings resembling each other very closely. In all three species the 
cotyledon petiole shows a double bundle, the halves of which diverge 
widely. The cotyledon traces enter the hypocotyl with isolated central 
protoxylem in the cotyledonary plane flanked by metaxylem groups, 
beyond which are the phloems in the diagonal positions. 
In Alnus incana and A, glutinosa normal diarch structure is attained in 
the hypocotyl by union of neighbouring phloem groups in the intercotyle- 
donary plane together with compacting of the xylem secants in the cotyle- 
donary plane. In A. glutinosa the phloem groups remain apart for a longer 
period than in A, incana. In both species the root is diarch. 
In Alnus cordifoUa (Fig. 9) the structure of the node and of the 
upper part of the hypocotyl resembles that found in the species above 
