472 PHARMACEUTICAL BOTANY 
mit a single, yellow, nodding flower, which is often marked with 
purple stripes. The flower consists of a torus or receptacle which 
will be observed as the upper swollen end of the flower stalk 
(scape). Inserted upon it, passing from periphery toward the 
center, will be noted four whorls of floral leaves which, in order, 
are calyx, corolla, andrecium and gynecium. The calyx is composed 
of three lance-shaped and recurved, yellow parts called sepals; 
the corolla of three similarly looking parts called petals which 
Fic. 355.—Dog’s tooth violet (Erythronium americanum). Stages of development 
from the seed. 1-5 show the stage of development in each of five successive years. 
Full explanation in the text. 6, Bulb showing a surface bud (the sprout has been 
destroyed). (Gager after F. H. Blodgett.) 
alternate in position with the sepals. Both of these whorls are 
collectively called the fperianth or floral envelope. The 
androecium or male system of organs is composed of two whorls 
or circles of structures called microsporophylls or stamens. There 
are three stamens in each whorl. The outer whorl of stamens 
will be found opposite the sepals while the inner will be observed 
opposite the petals. Each stamen (microsporophyll) consists of 
an awl-shaped stalk or filament bearing upon its summit an 
oblong-linear body called an anther. The anther consists of two 
