THE BUD 185 
sionally axillary buds do not develop and are then called 
dormant buds. 
3. An adventitious bud is one 
which occurs on some position 
of the plant other than at the 
apex of the stem or in the axil of 
aleaf. Such buds may be seen 
developing along the veins of a 
Begonia leaf or in the notches 
along the margin of a Bryo- 
phyllum leaf after these have 
been planted in moist soil for 
several days. The roots of the 
poplars, willows, cherries and 
many other trees develop 
adventitious buds underground 
which develop suckers which 
may eventually become mature 
plants that lead an independent 
existence. 
4, An accessory bud is an extra 
bud which forms in or near the 
leaf axil. These may be seen 
on the young stems of the Red 
Maple. 
5. A sub-petiolar bud is one 
arising beneath the basal part of 
the petiole or leaf stalk, so that 
when the leaf falls off the bud 
becomes exposed, as in the 
Buttonwoods. 
CLASSIFICATION OF BupDs 
AccoRDING TO THEIR 
ARRANGEMENT ON THE STEM. 
1. When a single bud is 
» ferminal leaf-bud 
AS 
a 
} flower- buds. 
x \stipule-sear 
J ..- J lower-bud-scars 
Fic. 116.—Cottonwood twig, two years 
old. (From Robbins after Longyear.) 
found at each joint or node of a stem, the buds are said to be 
alternate. 
2. When two buds are found at a node they are opposite. 
3. When several buds occur at a node they are whorled. 
