30 



FLOWERS. 



Raceme, Laburnum. 



other of these methods of displaying their blossoms. 

 There is, however, a very interesting exception to this 



in the common Dogwood. The 

 flowers, which are quite small, 

 are clustered in close heads, and 

 each head is surrounded by four 

 large white leaves, which are 

 called an involucre. These leaves 

 being very prominent and showy, 

 are often mistaken for the flower, 

 while they only act as appen- 

 dages; but they undoubtedly 

 have some use assigned them; perhaps it may be 

 to protect the delicate little blossoms from the cold 

 night-winds which are apt to prevail in the early 

 Spring, while they are in bloom. 



Most flowers require the action 

 of light to cause them to expand, 

 and many never open except un- 

 der the influence of the most bril- 

 liant sunshine. But there are a 

 few instances in which the con- 

 trary is observed. Far down in 

 the evergreen forests of South 

 America, when the sun has set 

 behind the tall groves of Palm 

 and Mimosa, and the glimmering twilight is fast fol- 

 lowing in its train, the magnificent flowers of the 

 Night-blooming Cereus may be seen just opening their 

 fair petals to catch the first rays of the full-orbed 

 moon. Travellers in the tropics describe it as a sight 



Fascicle, Sweet William. 



