COROLLA AND CALYX. 265 



these plants, and Hedwig, so famous for his 

 discoveries among them, were both of this 

 opinion, though the latter seems to have re- 

 linquished it. The organ in question is a 

 membranous hood, covering the unripe fruit 

 of these diminutive vegetables, like an ex- 

 tinguisher ; but soon torn from its base, and 

 elevated along with the ripening capsule. 

 See Engl. Bot. t. 558, &c. The great pe- 

 culiarity of this part, whatever it be called, 

 consists in its summit performing the office of 

 a stigma, as Hedwig first remarked. In 

 Jangermannia, t. 77 1> &c, the very same 

 part, differing only in usually bursting at the 

 top to let the fruit pass, is named by Lin- 

 naeus a perichcetiam, but very incorrectly, 

 as we have already hinted. 



Whatever office the Petals may perform 

 with respect to air and light, it is probable that 

 the oblong summit of the Spadix in Arum, 

 t. 1/298, answers the same purpose. When 

 this part has been for a short time exposed 

 to the light, it assumes a purplish brown 

 hue, which M. Senebier seems to attribute- 

 to the same cause which he thinks produces 

 the great heat observed in this Bower, the 



