Tough Calyx and Bracts. 127 



cartilage. The Bianthus ^olifer, of which I give 

 drawings (Plate III. fig. 114, a single flower; fig. 113, 

 a complete inflorescence), will serve as an example of 

 this tolerably extensive class of protective appliances. 

 In this flower the perianth (calyx as well as corolla) is 

 made of a very delicate tissue, and is not protected exter- 

 nally either by viscidity or by hair-like structures. 

 The nectar, moreover, in the recesses of the flower 

 is at such a very short distance from the thin calyx, 

 that it could be easily got at by gnawing laterally 

 through the perianth. This unprofitable expenditure 

 is, however, prevented by the arrangement and 

 character of the bracts. These are formed of a dry 

 membrane, almost like parchment, and closely in- 

 vest the fascicled flower-heads up to the very mouths 

 of the individual flowers ; and so tough are they, that 

 humble-bees or ants might work away for ever 

 with their jaws, and yet make no impression upon 

 them. 



That the crowding together of foliar organs would 

 also act as an impediment, and stop insects from thus 

 gnawing holes in the side of the perianth, is self-evi- 

 dent ; and I am therefore inclined to believe, that the 

 development of an epicalyx may be subservient to this 

 among other uses. In many cases the nectar has no 

 fewer than four foliaceous strata to protect it laterally, 

 namely, the corolla, the calyx, the epicalyx, and the 

 bract; so that it becomes excessively difficult, if not 



