i 7 8 
PHARMACEUTICAL BOTANY 
The flower stalk is known as the peduncle, and its prolongation the 
rachis, or axis of the inflorescence. 
The flower stalk of a single flower of an inflorescence is called a 
pedicel. When borne without such support the flower is sessile. 
A peduncle rising from the 
ground is called a scape , 
previously mentioned under 
the subject of stems. 
The modified leaves found 
on peduncles are termed bracts. 
These vary much the same as 
leaf forms, are described in a 
similar manner, and may be 
either green or colored. When 
collected in a whorl at the 
base of the peduncle they 
form an involucre, the parts of 
which are sometimes imbri¬ 
cated or overlapping, like 
shingles. This is generally 
green, but sometimes petaloid, 
as in the Dogwood. The 
modified leaves found on pedi¬ 
cels are called bracteolar leaves. 
The Spathe is a large bract 
enveloping the inflorescence 
and often colored, as in the 
Fig. 91.—Photomicrograph of longi- Calla, or membranous, as in 
tudinal section through a staminate Daffodil 
catkin of Comptonia asplenifolia X 10, . 
showing catkin axis (ax), anther-lobe (a), Indeterminate Inflores- 
and bract_(&). cences. —In the indeterminate 
or axillary anthotaxy, either 
flowers are produced from base to apex, those blossoming first 
which are lowest down on the rachis or from margin to center. The 
principal forms of this type are: 
Solitary Indeterminate. —The simplest form of inflorescence in 
which a single flower springs from the axil of a leaf. A number of 
