S4g BOTANt. 



from the top; but once inside, it finds it diflScult to escape 

 by that route on account of the incurved margins of the 

 opening, as well as the smooth sides of the slipper. It ac- 

 cordingly passes backward under the dependent stigma, 

 and escapes by squeezing between the column and base of 

 tbe slipper: in doing this it covers its back with sticky 

 pollen from the anther on the column. When it visits 

 another flower this experience is repeated; and as it passes 

 under the stigma in its endeavor to find an exit, some of 

 the pollen is left on its surface. 



622. Among the tropical Orchids there are some marvel- 

 lous fiowers. One of the most remarkable of these is a 

 large flowered species of Catasetum, native of South 

 America. The flowers are diclinous, i.e., the pollen and 

 the ovules are produced in different flowers. The column 

 of the staminate flower is furnished with a pair of slender 

 horns, one or both of which are sensitive. The pollen- 

 masses are curved and in a state of tension, like a curved 

 whalebone spring. Now, when an insect alights on the lip 

 of the flower and comes in contact with one of the sensitive 

 horns, the pollen-mass is instantly set free with a jerk suf- 

 ficient to throw it nearly a metre, and in such a direction 

 as to strike and adhere to the head of the insect. When 

 the insect visits a pistillate flower, the pollen-mass is in the 

 proper position to be brought in contact with the stigma, 

 thus effecting pollination. 



523. Much might be written about these truly wonderful 

 plants, but what has been said must suffice to call the at- 

 tention of the student to them. Our native species will 

 well repay a careful examination, while the exotic ones, of 

 which hundreds are now grown in conservatories, show a 

 greater variety in form and color of flower than can be 



