Dogbane and Milkweed 309 
butterfly’s preserves. For this intrusion he is 
dealt with as severely as poachers were under the 
forest-laws of feudal England. 
There is another variety of dogbane, the Indian- 
hemp, or Apocynum cannabinum, which bears 
smaller blossoms than the androszemifolium, blooms 
somewhat later, and is more widely distributed 
over the country. This flower has no callosities 
in its corolla, sets no snares for insect victims, and 
is apparently quite innocent of the crimes which 
one is inclined to lay to the charge of its first 
cousin. 
The common milkweed (Asclepias cornuti) (Fig. 
86) also imprisons insects, which sometimes die in 
captivity, and do no apparent good to the plant 
by their deaths. They have, however, invited mis- 
fortune, for though the milkweed is rich in honey 
and is visited by a large and miscellaneous com- 
pany, it can be fertilized, apparently only by bees, 
and perhaps by a few large flies. 
The milkweed is a peculiarly-constructed and 
very highly-organized flower. The sepals and the 
petals, each five in number, fold back as soon as 
the flower opens and press closely against the 
flower-stalk (Fig. 87, @). Inside them, standing 
upright in a ring, are five honey-jars or nectaries 
