OF PLANTS. 73 



vegetable world, and, in the fulfilment of their own 

 irrelative natural duties, casually exert so essential an 

 influence on the life of the plants, that one would almost 

 believe it was their proper destination. For, be they land 

 plants, the wind drives the enormous quantity of pollen 

 far and wide, and the air is often so filled with it that 

 sudden rain throws it down in visible quantity, as the 

 so-called sulphur-showers. Where there is such profusion, 

 a sufficient number of granules must of course reach their 

 destined resting place. If they be water plants, the 

 germens float in such a manner that the light waves wash 

 over them, and the pollen, driven about in the water, is 

 thus brought to its place. In the two great families, 

 especially, the Asclepiadaceae, to which belongs the Syrian 

 Silk-plant, and the Orchidacese, which, with their blossoms 

 imitating bright, splendid butterflies and strangely fashioned 

 insects, adorn the damp shades of the tropical forests; 

 in these two groups of plants especially is seen, the distinct 

 interference of living creatures in the reproduction of 

 plants. In them the pollen of each anther is glued 

 together by a matter like bird-lime, and it adheres so 

 firmly to the nectar-seeking insect, that he cannot get rid 

 of it. The nectaries are so situated in the flower, that 

 the insect, in order to reach them, must come into close 

 contact with the stigma, and thus the pollen is brought 

 to its destined place. We often see flies crawling on 

 the Silk-plant, with a number of such club-shaped pollen- 

 masses hanging to their legs, and in some localities 

 the bee-keepers speak of a peculiar disease of their indus- 

 trious little animals, " the club-sickness," which consists 

 solely in the adherence of so many pollen-masses of 

 Orchidaceae to the heads of the bees, that they are 

 disabled from flying, and thus are lost. A copious work 



