92 
of the four primitive rays, as in the first-noticed arrange- 
ment, hut occur as four new projections placed exactly 
midway between the first four, so that the stem now 
exhibits eight of these rays arranged like the spokes of a 
cart-wheel At first, the four secondary rays are very 
much shorter in length than the four primitive rays, but as 
the stem increases in age all the eight rays become of equal 
length. Even in this type some species exhibit an approach 
to the first type, by some of the primitive rays in the older 
stems having one or two lateral plates lying alongside 
them. 
Perhaps the most striking form of all the Bignoniacese 
which I have hitherto examined is one which unites the 
peculiarities of both the preceding arrangements, but carried 
to such an excess as that the cortical portion at 
last forms one half the bulk of the stem. Originally, the 
woody portion is arranged in the form of a cross, the bark 
filling up the whole space enclosed by the four arms of the 
cross. According as the stem increases in diameter, new 
cortical rays are projected into the four extremities of the 
woody mass, so that the arms appear to be bifid; these 
bifurcations also in their turn become bifid, and so the 
woody mass has its primary, secondary, tertiary, and qua- 
ternary divisions according to its age. Further, as the 
innermost cortical deposit — that surrounding the woody 
tissue — is very dark in colour, it throws into high relief the 
stellate outline of the woody portion. I have met with only 
one or two species of Bignonia which furnish this elaborate 
arrangement, and the specimens exhibited will show its 
striking character. 
The woody system of the stems belonging to this natural 
order is by no means uniform, but it requires careful study 
before a detailed description can be given. Nearly all the 
species, however, have numerous vessels of large diameter 
imbedded in the woody tissue, so that the stems are for the 
