SECT. I. EXCITABILITY. 447 



light of day ; they incline also towards the sun, and 

 follow his course, looking towards the east in the 

 morning, towards the south at noon, and towards 

 the west in the evening ; and again returning in the 

 night to their former position in the morning. Such 

 flowers are designated by the appellation of Hello- 

 tropes, on account of their following the course of 

 the sun ; and the movement they thus exhibit is 

 denominated their nutation. This phenomenon 

 had been observed by the ancients long before they 

 had made any considerable progress in botany, and 

 hadevenbeenintervoven into their mythology,having 

 originated, according to the records of fabulous his- 

 tory, in one of the metamorphoses of early times. 

 Clytie, inconsolable for the loss of the affections of 

 Sol, by whom she had been formerly beloved, and 

 of whom she was still enamoured, is represented as 

 brooding over her griefs in silence and solitude ; 

 where refusing all sustenance, and seated upon the 

 cold ground, with her eyes invariably fixed on the 

 sun during the day, and watching for his return 

 during the night, she is at length transformed into 

 a flower, retaining, as much as a flower can retain 

 it, the same unaltered attachment to the sun. This 

 is the flower which is denominated He Hot r opium Exempli- 

 by the ancients, and described by Ovid as Flos qui 



adsolemvertitur.* But it is to be observed that plura> 

 the flower alluded to by Ovid cannot be the Helio- 

 tropium of the moderns, because Ovid describes it 



* Metamorph. lib. iv, 1. 2,50. 

 4 



