12 MR. R. H. COMPTON: AN INVESTIGATION OF THE 
The root is tetrarch, four Y-shaped xylems surrounding a large pith. 
Fibres present in phloem. Though only four protoxylems are prolonged 
into the root, a large quantity of metaxylem is present in the form of many 
stem-like bundles between the protoxylems: this being the arrangement so 
far as 1 em. below the external collet. Sections at this point show a remark- 
able combination of root and stem characteristics. The transition is in fact 
effected far below the collet. The whole of the hypocotyl has a perfect stem 
structure : even the root protoxylems have superposed phloem groups. 
The transition is pronouncedly low, no other seedling examined surpassing 
it in this respect: this being doubtless correlated with its massive proportions. 
The general structure shows affinity with other Amherstiez. 
BAUHINIEE. 
BAUHINIA VARIEGATA, Linn. 
A middle-sized erect tree. The hypocotyl sharply narrows to a long tap- 
root. Lhe cotyledons are ovate-oblong, cordate at the base, with palmate 
venation. 
The root is tetrarch and contains a pith throughout its length. 10 mm. 
below the collet the xylem consists of four tangential bands with median 
projecting protoxylem and pairs of lateral metaxylem wings: these form a 
nearly continuous ring round the pith. Strong bands of fibres bound the 
phloem externally. 
As the axis dilates below the collet the xylem ring breaks up into four 
isolated protoxylem groups, each with a pair of metaxylems, and usually 
other groups of metaxylem are left between adjacent triads. On entering 
the hypocotyl the lateral protoxylems also divide and join their respective 
metaxylem groups. All the latter acquire new internal protoxylem of their 
own, and so become completely endarch. Thus a stem-structure is attained 
at the very base of the hypocotyl and continues throughout its length. 
The bulk of the xylem is reduced considerably as we ascend the hypocotyl ; 
the pith also increases in size and the cortex narrows considerably. Just 
below the node the xylem tends to collect into four main groups, two 
supplying each cotyledon. The polar protoxylems remain between the 
large cotyledonary bundles in the median plane ; and there are also a few 
small scattered bundles which pass out to the cotyledons between the two 
main groups. Each cotyledon also receives two long bands of phloem, 
separated only over the polar protoxylem. 
BavnurxiA Ноокеві, F, Muell. 
Cotyledons only just above ground. Hypocotyl narrowing slowly to a long 
primary root. Cotyledons ovate, slightly thickened. 
The transition phenomena agree very closely with those observed in 
