76 
PLANT MORPHOLOGY. 
stalk of the individual flowers is called a pedicel, while 
the main axis, or branch bearing the collection of 
flowers, is called a peduncle. The study of the arrange- 
ment of flowers on the stem is known as Anthotaxy. 
If we compare the flower clusters of morning glory 
with those of the poke weed, we will find that in the 
former the number of flowers that may be produced is 
limited because the middle flowers of the group, cor- 
responding to the apex of the branch, mature first; 
in the poke weed, on the other hand, the end of the 
branch has a large number of flower buds, and as 
these develop others continue to be formed. It is 
obvious that in the latter case the number of flowers 
that may he produced is more or less indefinite, and 
this kind of anthotaxy, or inflorescence, is known as 
indeterminate or indefinite inflorescence, while in the case 
of the morning glory, the inflorescence is said to be 
determinate or definite. 
The indeterminate or indefinite inflorescence is the 
most general and includes the following kinds: In 
poke weed the individual flowers are of about the same 
size, and these are arranged along a central axis, or 
rachis, the inflorescence being known as a raceme; in 
cusso the individual flowers are replaced by a cluster of 
flowers, constituting a compound raceme or panicle ; in 
the cultivated cherry the rachis is somewhat shorter 
than in the raceme, and the pedicels of the flowers are so 
elongated that all of the flowers attain nearly the same 
height or level, this form of inflorescence being known 
as a corymb; in the milk weed the rachis is entirely 
suppressed and the flowers, which have pedicels of the 
same length, arise from a common receptacle, this form 
of inflorescence being known as an umbel; in the 
Umbelliferae a flower cluster takes the place of the 
individual flowers of the umbel, and this is known as a 
