Davey. — Seedling Anatomy of certain Amentiferae. 589 
for Calycanthns occidentalism in which the phloem strands present in the 
cotyledonary plane of the root die out in the base of the hypocotyl. 
Betuia excelsa and B. p limit a. These are very small seedlings, resem- 
bling in habit those of A Intis, In both species the root is diarch and the 
transition features are precisely similar to those of A Inns incana. 
The following features occur in all the above species of A Inns and 
Betuia, The first plumular leaf is prominent, and vascular traces from this 
and the succeeding leaf are present at the cotyledonary node in the inter- 
cotyledonary plane. These consist almost entirely of secondary tissue and 
do not extend far into the hypocotyl. At an early stage the cambium 
develops so as to link the cotyledonary and plumular traces together, 
producing two bands of vascular tissue extending at right angles to the 
Figs. 12 and 13. Carpinus Betulus. 12. Vascular system of hypocotyl showing protoxylem 
in cotyledonary plane. 13. Root of same. cot. and intercot. indicate the respective planes. 
cotyledonary plane, as in Myrica. An endodermis showing the charac- 
teristic radial dot makes its appearance at a high level in the hypocotyl. 
Carpinus Betulus and C. Ostrya. These seedlings are larger than 
those of Alnus. The cotyledons are slightly fleshy and remain within the 
seed longer than do those of the preceding genera. 
The anatomical features of both species are exactly similar. The 
cotyledon petioles possess each a large double bundle with widely diverging 
halves which enter the node at the diagonal corners as collateral endarch 
strands. Centrally placed protoxylem is present in the base of the petiole 
and at the cotyledonary node, but dies out immediately below it. In 
descending the hypocotyl each of the four metaxylem strands becomes 
divided into two by the failure to continue differentiation of its median 
elements (Fig. 12). The eight groups of metaxylem thus produced 
gradually * approach ’ the neighbouring cotyledonary or intercotyledonary 
planes by means of the appearance of earlier llgnified elements on the side 
