224 : ; DEVELOPMENT OF LEAVES, 
A digitate leaf is nothing but a pinnate leaf with the leaf- 
lets umbelled inserted, instead of along the petiole. In the 
young state it is not distinguishable from an ordinary pin- 
“nated leaf, such as that of Boswellia, with this exception that 
the terminal leaflet is the first developed, andi is the largest 
afterwards. 
See Aralia digitata. 
A Bauhinia leaf is not distinguishable from an ordinary 
leaf in its young state, it is then chiefly remarkable for the 
lamina on either side being contracted at the base. 
Itis in the young state not actually distinguishable from 
the very young state of the leaves of Inga bigemina, which 
consist of three points, of which the centre is much the 
largest, the lateral approached to its base. 
A bipinnate leaf is nothing but a repetition of a pinnate, 
it is in fact at first pinnate and primarily simple, then 
along each side of the central furrow, an elevated rim, or 
border appears, then this becomes divided into a number of 
points. 
These points growing to a certain extent, then present the 
furrow, and the rounded margins or elevated rim, then again 
points of the future pinnules. 
So that nothing can be more obvious than that the bipin-- 
nation is a result of ulterior development. 
Amphilophium mutisii is proved by development to have 
. a pinnate leaf, of which the two lowermost pinnze become foli- 
aceous. ; 
The matured form of a pinnated leaf is pari-pinnàtum, in 
which case the point of the petiole, the part first formed 
remains the same, and in accordance with the direction of 
development, ceases to produce a lamina. 
In the impari-pinnate leaf, the point first formed and last 
laminiferous becomes completely changed, the sides spreading 
out into leafy expansions, and the midrib becoming as in 
the other veins. This appears to me remarkable, there is 
not even an apiculus or mucro to point out the original entire 
elamelliferous punctum ! ! 

