MENGE The External Form of Plants. — IOI 
trifoliolate. When the petiole divides at its apex into two 
main divisions, each of which bears several leaflets, it is 
pedate (Fig. 183). The 
pinnate leaf has its leaf. 
lets arranged on -each 
side of a common elon- 
gated petiole, which is — 
then called the rachis. 
If the rachis ends in a 
terminal leaflet [so that 
the number of the pinnze 
is uneven] the leaf is 
unequally pinnate or z7- 
paripinnate (Fig. 184); 
if the number of leaflets 
is an even number it : 
-~ js partpinnate or equally Fic. 178.—Palmatifid leaf of the castor-oil 
pinnate (Fig. 18 5 ); and plant, Ricinus communts. 
in this case the rachis may run into a tendril or a point 
(Fig. 185), or may end abruptly. The leaflets may be 
Fic. 179.—Trilobed leaf of the hepatica. Fic. pseu eden leaf 
of the oak. 
opposite to one another on the rachis (Fig. 184), when 
each pair forms a ‘7uguz2,’ or they may be alternate (Fig. 
