227 
These results clearly show that the possession of a special 
discriminatory irritability by certain highly sensitive tendrils, 
as suggested by Darwin, is only apparent and not real, the 
non coiling of such tendrils, when in contact with one another, 
being due to causes applicable to all tendrils. 
Dalbergia linga. 
An extremely interesting transition form is afforded by the 
clasping organs of this plant. The compound pinnate leaf has 
3 to 4 opposite pairs of secondary leaves, each with 4 to 8 
pairs of almost sessile pulvinate leaflets. The basal part of each 
secondary petiole forms a markedly swollen pulvinus, bearing 
at its distal end a pair of minute stipules, and being largest 
and longest in the apical pair of leaves, smallest in the basal. 
These pulvini, along with the pulvini of the leaflets and the short , 
thick pulvinus at the base of the main petiole, are all motile 
organs and it is by means of them, that the leaflets are able 
to protect themselves from excessive illumination and expose 
themselves fully, when the light is not too strong. 
The terminal pair of leaflets are peculiar when young, inas- 
much as the pulvinus is backwardly curved and develops more 
rapidly, but the leaflets more 
slowly, than in the basal pair. 
In the 2.4 and 3 pair the 
pulvini are also somewhat 
longer than in the basal pair, 
but are nearly straight and 
forwardly directed. The ter- 
minal pair thus assume a 
very hook like appearance and 
it was to this peculiarity that 
Prof. Penzia directed my at- 
tention. es 
If the pulvinus of a termi-  & 4 
nal pair of secondary leaves 
comes into contact with a support, it twists around it, thickens , 
