438 



HUTCHINSON'S POPULAR BOTANY 



caudicles are ruptured without much, difficulty, and thus the balls of pollen 

 would be left on the viscid stigmatic surface of a female flower/' 



In striking contrast to the Catasetums are those Orchids which secrete 

 great quantities of nectar, like Coryanthes. The sweet fluid secreted by 



the strange-looking horns of Cory- 

 anthes macrantha, for example, drips 

 so plenteously into the bucket- 

 shaped portion of the labellum at 

 the period of flowering that it half 

 fills the bucket indeed, would 

 quite fill it, were it not that the 

 receptacle is provided with an 

 overflow spout ! Above the bucket 

 is a hollow chamber, walled and 

 ceiled with fleshy ridges and pro- 

 vided with two side entrances. 

 " The most ingenious man." says 

 Darwin, "if he had not witnessed 

 what takes place, would never 

 have imagined what purpose all 

 these parts serve. But Dr. Criiger 

 saw crowds of large humble-bees 

 visiting the gigantic flowers of 

 this orchid not in order to suck 

 nectar, but to gnaw off the ridges 

 within the chamber above the 

 bucket; in doing this they fre- 

 quently pushed each other into 

 the bucket, and their wings being 

 thus wetted, they could not fly 

 away, but were compelled to crawl 

 out through a passage formed by 

 the spout or overflow. Dr. Criiger 

 saw a continual procession of bees 

 thus crawling out of their invol- 

 untary bath. The passage is nar- 

 row, and is roofed over by a column, 

 so that a bee, in forcing its way 

 out, first rubs its back against the 

 viscid stigma, and then against 

 the viscid glands of the pollen-masses. The pollen-masses are thus glued 

 to the back of the bee which first happens to crawl out through the passage 

 of a lately expanded flower, and are thus carried away. When the bee, thus 

 provided, flies to another flower, or to the same flower a second time, and 



Photo by] 



FIG. 541. PYRAMIDAL ORCHIS 

 (Orchis pyramidalia). 



Somewhat like the Fragrant Orchis, but with larger flowers. 



The flower-spike is at first pyramidal. The long spur contains 



no .nectar, and visiting insects have to suck at the lining 



membrane. 



