204 
Artabotrys. 
The hooks are curved backwards in a single turn, and are 
divided into three regions, (1) a basal or peduncular, (2) a median 
and (3), an apical portion. Between 1 and 2, and 2 and 3, and 
at the apex, are buds, which may one or all develop into leafy 
branchs or flowers. Without contact, hooks bearing flowers are, 
when adult, markedly smaller, than when the buds do not 
develop, or when only leafy branches are formed. Such hooks 
also are so recurved as to enclose only a very small space, 
i. e. are not likely to become attached. With contact, the 
difference is still more marked, flowering hooks being much 
less irritable, than non flowering ones are. (See also TREvB, 
lc. p. 61). If the flowers are removed, the hook, when sub- 
jected to contact, grows more than normally, but still only 
little in comparison with a non flowering hook under similar 
conditions. 
The curvature, which the hooks assume, is the result of nor- 
» mal growth, and takes place independently of 
1 contact, though contact applied, when the hook 
\| is young, may hasten its growth and bending, 
but does not cause any actual increase 
either its length or curvature. 
In measuring the hook for an increase of 
thickness, the regions 1, 2 and 3 are measured 
at the points shown in Fig. 2. The meas 
rements for a typical adult hook, without 
contact, are (1) 4 cm. 210 . 270; (2) 2.8 om. 
Phd coy. 4 s-S A—P 
LY 105 . 160; (3) 0.8 em. 80 . 145. 
Dy es The influence of contact is perceptible under 
# favourable conditions by the 3*4 day. Thus 10 
just adult hooks, attached to fixed supports, averaged: 
a 
te ‘ “gy 
S—S A—P SS A—P §S—S A—P S—S A—P S—S A—P SS ut 
on the 1st day. 235.320 [235.325]; 145 . 935 (150 . 240) ; 95. 140 (100. 145] 
and on the 31 day. 245.350 [240.330]; 155.265 [150.250]; 100.145 [100 . 160] 
