SECT. III. INDUCTION OF PARTICULAR PROOFS. 315 



morning, when it again rears its head, sometimes to 

 the height of several inches, and presents its ex- 

 panded petals to the culminating sun. A pheno- 

 menon still more singular is related by Theo- 

 phrastus as occurring in what he calls the Lotus, 

 perhaps the NymphcEa Lotus of Linnaeus ; of which 

 he says, though only on report, that in the 

 Euphrates the flower keeps sinking till midnight, 

 when it again begins to ascend, but more rapidly as 

 day advances, elevating itself to the surface about 

 sun-rise, and afterwards expanding and rearing its 

 head high above the water. * Some flowers are so 

 very susceptible to changes of atmosphere as to shut 

 up their petals even upon the approach of rain. 

 One of the most remarkable examples of this sort is 

 that of the Anagallis arvensis, or Poor Man's 

 Weather-glass, which appellation it seems to have 

 obtained from its peculiar susceptibility, always 

 shutting up its blossoms even upon the slightest 

 symptoms of approaching rain, except in the case 

 of a sudden thunder-storm, when it happens to be 

 taken by surprise : but Sir J. E. Smith says he has 

 reason to think that its susceptibility is apt to be 

 impaired, and sometimes totally destroyed by long 

 continued wet;-}- and Linnaeus remarks that flowers 

 in general lose this susceptibility when the anthers 

 have discharged their pollen. 



Obs. 4. -The pollen is generally discharged from From the 

 the anther in such a manner as to ensure its dis- 



Theoph. 106, Aldi, -f Introduction, p. 32p. len ' 



