Davey . — Seedling Anatomy of certain Amentiferae. 579 
of the Fagales, a cohort of considerable size which presents instances of all 
the above-mentioned modifications. 
The Amentiferae furnish interesting examples of the various degrees of 
connexion between the vascular system of the primary root and hypocotyl 
with the strands of the plumular leaves, similar to those which have 
been observed by Mr. Compton 1 in the Leguminosae. The traces of the 
early plumular leaves may show double bundle or triad structure to 
a marked degree. 
Verticillatae. 
Casuarinaceae. 
Casuarinci. The species examined possessed slender, wiry seedlings ; 
there are two epigeal cotyledons and a relatively long hypocotyl. The 
plumular axis develops earlier than is usual for this type of seedling. 
In the youngest individuals obtained, the minute bud enclosed within the 
short cotyledonary tube possessed three leaf whorls with well-differentiated 
vascular system. At the first plumular node there is a pair of rudimentary 
leaves alternating with the cotyledons, while successive nodes bear leaf 
sheaths, like those on the adult branches, consisting of four to six members. 
Well-developed buds which expand early are present in the axils of the 
cotyledons. 
Casnarina equisetifolia . The cotyledons fuse into a short tube above 
the node. In the epicotyl each member of the leaf whorls contributes 
a single vascular strand. At the cotyledonary node six such strands are 
present, two in the intercotyledonary plane (from the first pair of leaves) 
and four diagonally placed (related to the members of the second whorl). 
These strands close up, forming two groups of three in the intercotyle- 
donary plane. The cotyledons show an extended double bundle in which 
the medianly placed protoxylem becomes exarch at the node. Two lateral 
strands are present in the base of the petiole resulting from the union 
of more numerous ones at higher levels. The laterals sometimes approach 
the diverging halves of the central strand so that their phloem portions 
merge. The three strands of each cotyledon enter the axis without change 
in their relative positions. The central cotyledonary protoxylem continues 
downwards in the cotyledonary plane, while the metaxylem diverges from 
it. The metaxylem and protoxylem of the laterals approach the inter- 
cotyledonary plane, while elements of an earlier stage of differentiation 
appear in connexion with it on the sides adjacent to the poles. At a 
relatively high level in the hypocotyl the lateral metaxylems become 
united across the intercotyledonary plane, owing partly to contraction 
of the stele as a whole, and partly to the presence of centrally placed 
protoxylem which is not differentiated near the node. The phloem of the 
1 loc. cit. 
