ij2 Blackburn.— On the Vascular Anatomy of 
parenchyma cells, and there are no true medullary rays. This feature is 
found in the majority of the species, at the nodes in the aquatic species and 
in the secondary wood of R. arvensis , which is otherwise quite comparable 
in its seedling features with such a form as Aquilegia , as it shows a quite 
definite ring of bundles in the early stages of the seedling. 
2. The leaf-trace strands have little primary xylem in their axial 
portions and its place is taken by very early formation of secondary tissue. 
This feature is found also in Aconitum , but there is no siphonostelic 
appearance in that genus owing to the formation of wide principal 
medullary rays. 
3. The secondary xylem consists largely of isodiametric tracheides. 
and the elements are frequently tangentially elongated. These features 
seem to be due to the 
telescoping of the axis 
combined with its rapid 
radial expansion in many 
of the species. 
Trollius. There is 
a ring of bundles con- 
nected by a poorly de- 
veloped cambium in the 
rhizome. The aerial stem 
possesses a ring of bundles 
surrounded by a sinuous 
endodermis and with no 
interfascicular cambium. 
The seedlings are 
not unlike those of Ra- 
nunculus in external 
appearance. T. pumile 
showed a tendency to 
fusion of the cotyledons 
by one margin. Ana- 
tomically they also show resemblances to that genus. 
T. asiaticus. The plumular anatomy resembles that of R. gramineus\ 
but a greater development of primary tissue distinguishes it, which is 
observable even after the formation of a quantity of secondary tissue of the 
‘ Ranunculus ’ type. See Text-fig. 18, which is part of the ring at the first 
node and shows distinctly the median trace of the second plumular leaf. No 
endodermis has been demonstrated, but the evidence is insufficient to state 
that it is absent. At the cotyledonary node are one or more lateral roots 
whose vascular system seems largely supplied by plumular tissue. 
T. pumile. Only one seedling has been examined. The fusion of the 
Text-fig. 18. Trollius asiaticus. Part of first plumular 
node. M 2 is median trace of second leaf. 
