THE LEAF 245 
orientation, to still another in which, as in Nepenthes, all of the 
bundles form nearly a cylinder. Finally, in Ficus, Geranium, 
Podophyllum and other plants showing completely formed cylin- 
drical petioles, the bundles form a continuous ring enclosing 
pith and surrounded by cortex and epidermis, as in Dicotyl stems. 
STIPULES 
Stipues are lateral leafy or membranous outgrowths from 
the base of the petiole at its junction with the stem. They may 
be divided into two groups, viz.: lateral and axillary. The lateral 
group includes four types, namely, free lateral, lateral adnate, 
lateral connate and lateral interpetiolar. 
Free LATERAL STIPULES are seen in Leguminosae, Rosacea, 
Beeches, etc. They are free on either side of the petiole and 
supplied by vascular tissue from the petiolar bundle mass. In 
appearance and duration they may be either green, foliaceous 
and persistent or membranous to leathery, scale-like and cadu- 
cous. Caducous scaly stipules only function as bud scales, forming 
a protective covering to the bud through the winter and fall in 
spring as the buds expand. Cf. Fig. 163 (10). 
LATERAL ADNATE STIPULES are such as fuse with and are 
carried up with the petiole as wing-like appendages. ‘This type 
is seen in the Roses, in Clovers, etc. 
LATERAL CONNATE STIPULES are such as join and run up with 
the petiole to form a structure which is called a Licute. This 
structure is common to the Gramineae or Grass family. (See Fig. 
164.) 
LATERAL INTERPETIOLAR STIPULES are common to many 
species of the Rubiaceae. ‘This family has opposite leaves and in 
some of the genera, as Cinchona, one stipule from each leaf on 
either side of the stem unites by its margin with the margin of 
the other stipule to form an interpetiolar stipule. In this way a 
stipule is formed on either side of the stem between the opposite 
leaves. 
The AxILLAry Group represents stipules which stand in the 
axil of the leaf with the stem. Such may be Free AxILLary 
STIPULES, arising as distinct processes, or CONNATE, when the two 
