ON THE POWER OF MOVEMENT IN PLANTS. 



155 



Dandelion, Nipplewort, and Blue 

 Convolvulus ... ... ... opens at 5 — 6 a.m. 



Then, some flowers close at certain hours. Of these, just two or 

 three suffice. Goatsbeard closes at noon. Hence, the name given 

 to it by the dwellers on the Wye, of * ] ohn Go-to-bed-at-noon.' 

 You seldom or never see this vary outside the limits of 11.45 ^^^ 



12.15. 



Pimpernel 

 Marigold 



closes at 3 p.m. 



jj )) 4 5 >> 



J) )j 5 )) 



towards sunset 



Yellow-wort ... 



JLJaisy ••• ... ... 



Those opening at 6 p.m. or later, are really night-flowering 

 plants, and to make up for being unable to show their colours they 

 are all fragrant to a high degree, and so attract the night-moths as 

 their fertilizers. 



Some flowers, such as the Red Sandwort, just named, close 

 instantly on being plucked ; others once opened remain open 

 until they wither, as do most Orchids. Others, like the Commercial 

 Flax {Liiimn)^ close a few hours after expanding, never to open 

 again. 



Some vary in their time of expansion. Water-lily remains open 

 for twelve hours ; Purslane closes after an hour's expansion at 

 noon. 



All these movements depend not on the Direction^ but on the 

 Intetisity of Hght ; it is needful to mark this, as will be seen. The 

 Mechanism of the movements is not so well known as that of the 



