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 caHed 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 

 Calla, or membranous, as in 

 the Daffodil. 



Indeterminate Inflores- 

 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 



PIG. 91. Photomicrograph of longi- 

 tudinal section through a staminate 

 catkin of Comptonia asplenifolia X 10, 

 showing catkin axis (ax) , anther-lobe (a) , 

 and bract (6). 



