(137 ) 
median section along the plane of symmetry of one of the 
leaves. We see that the two angles between the petiole and 
the leaf-surface are very unequal. The acute angle (a) is at 
C 
B ee 
A Ee 
Fic ropound leaf of 
a ar guinguefolia or 
Lupinus albus. D,The removed 
leaflet in operated series. 
Fic. Diagram to illustrate 
the ineluiation of the petiole to 
the leaf-surface. 
Fic. 3. Compound leaf of 7ri- 
Solium pratense. Z,'The removed 
leaflet in operated series. 
the base of the leaf-system and the leaflet on the side opposite 
to it is the terminal leaflet. This general description holds 
for all three species. The value of the angle a, however, is 
not the same in the different cases. /. 2 is a diagram of 
the leaf system of either Parthenocissus or Lupinus as seen 
from above. The double line represents the projection of the 
petiole. The terminal leaflet is lettered C. Starting at the 
left of the petiole and going in a clock-wise direction we get 
