the Young Epicoty l in some Ranalean Forms. 155 
In Aquilegia there is a single ring of bundles with fascicular cambium 
only, whereas in Thalictrum they are arranged in two or three concentric 
circles. Anemone shows various forms of anatomy in the different species. 
There is commonly a somewhat irregular ring of bundles, but medullary 
bundles and separate endodermal sheaths are among the anomalies found. 
The descriptions of the adult anatomy of the forms described are taken, 
for the most part, from the published works of M. Marie and Mr. Worsdell. 
Ranunculaceae. 
Aquilegia. Marie states that there is a ring of bundles with a well- 
marked fascicular cambium in the adult stem of Aquilegia. Small inter-? 
calary bundles are also present. The seedlings are small and somewhat 
wiry in texture. The plumular internodes of the seedling are very short 
and hidden by the sheathing bases of the foliage 
leaves, which have long petioles and consist of three 
practically sessile leaflets. The phyllotaxis is two- 
fifths. The cotyledons are ovate and stalked and are 
joined below to form a short cotyledonary tube (see 
Text-fig. 1). Three species, A. vulgaris , A. alpina , 
and A. canadense , have been examined, of which the 
first is somewhat larger, but otherwise they show 
almost identical features both morphologically and 
anatomically. The vascular cylinder consists of 
a ring of about twelve strands. Secondary thicken- 
ing begins at an early age (see PI. XIII, Fig. 1). The 
sheathing bases of the foliage leaves overlap and so 
completely encircle everything within them. Each 
plumular leaf supplies three bundles to the central 
cylinder, and these enter the ring at an angle 
of about 120 0 from one another, so that the lateral strands of adjacent 
leaves cross. The plumular bundles are reduced to six above the cotyle- 
donary node, and these strands arrange themselves in groups of three on 
either side of the cotyledonary plane (see PI. XIII, Fig. 2). The double 
bundles from the cotyledons are inserted between these two groups, which 
then rapidly become reduced to single bundles. The phloem groups from 
the cotyledonary strands fuse with the plumular phloems and a diarch 
arrangement is attained. The pith and plumular tissue rapidly decrease as 
the lower levels of the hypocotyl are reached and typical root structure 
appears. 
Thalictrum. This genus has been very fully studied from an anatomical 
point of view by M. Mansion . 1 A very large number of bundles are 
arranged in the aerial parts of the adult stem in such a way as to resemble 
1 Loc. cit. 
Text- fig. i. Aquilegia 
vulgaris, x i§. 
