THE BOTANIC GARDEN. I 7 I 



and many grasses, scarcely distinguishable by 

 scientific characters, but differing in the rapidity 

 of their growth, and of very unequal value in 

 rural economy. Flowers constantly succeed 

 each other throughout the year, from the daphne 

 to the species of hellebore called Christmas-rose, 

 and January is the only month in which none are 

 found except in the orangery. 



Many curious phenomena are observed in this 

 vast assemblage of plants, such as the opening of 

 flowers at a fixed hour —some unfolding at the 

 dawn, as certain species of rock-rose, cistus ; 

 some at mid-day, as several jico'idece, and others 

 at sunset, as the mirabilis jalapa, several of the 

 ohagrce, etc. Some species foretel the weather, 

 as the small Cape marygold, calendula pluvialis, 

 and the Siberian sowthistle, sonchus sibericus, 

 the first of which opens and the second shuts, in 

 the morning, when the day is to be fine. The 

 sleep of plants, which presents itself under 

 forms so different, not only in different families, 

 as the leguminosce and malvacece, but in neigh- 

 bouring genera, as the mimosa and cassia, and 

 even in different species of the same genus, 

 as the milk-vetch, astragalus, can be properly 

 observed only when a great number of species 

 are assembled in the same exposure ; and these 

 phenomena are the more interesting as they are 



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