OF PLANTS. 199 



The SEEDS themselves are packed up in a capsule, a 

 vessel composed of coats, (PL XXXIV. fig. 1.) which, 

 compared with the rest of the flower, are strong and tough. 

 From this vessel projects a tube, through which tube the 

 ferina, or some subtile fecundating effluvium that issues 

 from it, is admitted to the seed. And here also occurs a 

 mechanical variety, accommodated to the different circum- 

 stances under which the same purpose is to be accomplish- 

 ed. In flowers which are erect, the pistil is shorter than 

 the stamina; (PI. XXXIV. fig. 2,) and the pollen, shed 

 from the antheree into the cup of the flower, is caught in 

 its descent by the head of the pistil, called the stigma. But 

 how is this managed when the flowers hang down, (as 

 does the crown imperial, for instance) and in which posi- 

 tion, the farina, in its fall, would be carried from the stig- 

 ma, and not towards it ? The relative length of the parts 

 is now inverted. The pistil in these flowers is usually 

 longer, instead of shorter, than the stamina, (PI. XXXIV. 

 fig. 3.) that its protruding summit may receive the pollen 

 as it drops to the ground. In some cases, (as in the nigcl- 

 la,) (PI. XXXIV. fig. 4.) where the shafts of the pistils, 

 or styles are disproportionably long, they bend down their 

 extremities upon the antherse, that the necessary approxi- 

 mation may be efiected.* 



* Amongst the various means which nature has provided for the 

 , purpose of assisting the impregnation of plants, that afforded by the 

 agency of insects is not one of the least. In the spring and summer 

 months numerous species of these lively little beings may be seen in 

 almost every expanded flower ; and whether they are in search of 

 honey which is contained in the nectaries of many flowers, or what- 

 ever may be the object of their attraction, by being continually on 

 the move, they, no doubt, further the dispersion of the pollen, and thus, 

 in a great measure, contribute to the fertility of the plants they visit. 



In many plants, as those which belong to the Linnoean class dicBcia, 

 where the stamens and pistils are in separate flowers, and those flowers 

 situated on two separate plants of the same species, the operation of 

 insects, or the efficacy of winds is indispensably necessary to the per- 

 fecting the fruit, by transporting the pollen of the one to the stigma of 

 the other. 



Some plants, indeed, that have perfect, or united flowers, have the 

 anthers so situated that it is almost impossible the pollen can, of itself, 

 reach the stigma ; in this case insects generally become the auxiliaries 

 to the fertilization of the seed. An instance of this may be seen in the 

 aristolochia dematitis. " According to Professor Willdenow, the flow- 

 er of this plant is so formed, that the anthers of themselves cannot im- 

 pregnate the stigma; but this important affair is devolved upon a 

 particular species of tipula. (T. pcnnicornis.) The throat of the 

 flower is lined with dense hair, pointing downward so as to form a 



