HOW THE WILD FIOWEES GBOW. 27 



Some flowers go through periodic changes of colour ; 

 others change their perfume with the changing hours ; 

 others their taste. Many plants are weather prophets : 

 some keep their faces to the sun; others close at 

 periodic times. The goafs-beard, for instance, closes 

 at noonday, and has received the popular cognomen of 

 " Jack Go-to-bed ; " and it is very doubtful if its first 

 name is not a corruption of the latter. Linnaeus was 

 enabled to construct what he called a " Tiorologium 

 flora" or floral clock, by strict attention to these 

 habits of the flowers. Thus the common morning 

 glory opens at dawn, the star of Bethlehem a little 

 after ten o'clock, the ice plant at twelve o'clock at noon, 

 at which time the goafs-beard and morning glory close, 

 unless, indeed, the day is cloudy, when the latter re- 

 mains open the whole day. The four-o'clock opens 

 about that time in the afternoon ; the flowers of the 

 thorn-apple and the evening primrose open at sunset; 

 and those of the night-flowering cereus when it is dark. 

 The white water-lily closes its flowers at sunset, and 

 sinks beneath the water for the night. In the morning 

 it is buoyed up by the expansion of its petals, and 

 again floats like a Naiad on the surface as before. The 

 slumbering and awakening o plants is not a poetic 



