STRUCTURE 54 
the petals and sepals? Draw a petal and a sepal (x1). 
If either the petals or sepals differ in form, draw one of 
each kind, showing the difference. 
Androecium.—How many stamens does the androec- 
cium contain? The distal end of the peduncle to which 
the floral organs are attached is called the receptacle. 
Are the stamens attached to the receptacle or to the 
petals? If not to the petals, are they attached directly 
above or between the petals? A stamen is composed of 
two parts, a rather slender stalk-like part, called the 
filament, and a more or less enlarged part called the 
anther. Draw a stamen, side view (x2). Examine sev- 
eral flowers, some just open and some much older. In 
what respect do the anthers differ? Do you find a yel- 
lowish powder-like substance, pollen, on any? If not, 
let the instructor give you some. Mount a little dry 
and study. Pollen is composed of numerous small 
bodies called pollen grains. Each pollen grain usually 
consists of a single cell. Put some water on your speci- 
men. Make an enlarged drawing of a typical grain. 
Exp. 38: Mount a little pollen of sweet pea, be- 
gonia, common locust, mandrake or sweet-strawberry 
bush in 10 per cent. sugar solution. Draw one of the 
pollen grains and then put the slide into a damp cham- 
ber. Examine the grains thoroly every day, especially 
near the edge of the cover glass. As soon as there is 
any marked change in form, draw a single grain show- 
ing the change. Twenty-four hours later make draw- 
ings again showing further changes. Conclusions? 
Make cross and longitudinal sections of some large 
anther taken from a bud; study these sections and note 
