242 PLANT FAMILIES: MONOCOTYLEDONS. 



A number of species of orchids are distributed in temperate 

 regions. 



393. Cypripedium or lady-slipper. One species of the lady- 

 slipper is shown in fig. 208. The labellum in this genus is 

 shaped like a shoe, as one can see by the section of the flower 

 in fig. 209. The stigma is situated at st, while the anther is 

 situated at a, upon the style. The insect enters about the 

 middle of the boat-shaped labellum. In going out it passes up 

 and out at the end near the flower-stalk. In doing this it 

 passes the stigma first and the anther last, rubbing against 

 both. The pollen caught on the head of the insect will not 

 touch the stigma of the .same, but will be in a position to come 

 in contact with the stigma of the next flower visited. 



Exercise 65. 



394. The orchid. Take one of the orchids, the lady-slipper (cypripedium) 

 for example, and make out the parts of the flower, and the relation of the 

 different members. Study the structure of the flower with reference to the 

 pollination by insects, with the aid of the text, and determine the course 

 which the insect takes to effect cross-pollination. 



Material. Entire plants in flower, including the bulb. This is usually 

 buried deep in the soil, and should be collected fresh if possible. Some of 

 the smaller plants, not in flower, should also be at hand. The plant flowers 

 during May in the northeastern United States. It is represented in other 

 sections by different species. In sections where a species of this genus cannot 

 be obtained another of the orchis family may be employed. (Apparatus. Dis- 

 secting microscopes, or tripod lenses (the former are better), dissecting nee- 

 dles, scalpel. The apparatus will not be repeated for the following exercises.) 



