324 The Field Naturalist 's Quarterly November 



This is to ensure pollination, and probably the stamen 

 loses all its pollen at one stroke, as it never regains^ its 

 old position. Each stamen is capable of independent 

 action. 



The stamens of Centaureas are irritable when touched, 

 for you can see the stamens jerk spasmodically when the 

 fingers are passed quickly over the flower-head. 



The Venus' Fly-Trap (Dionata), a carnivorous North 

 American plant, has bright green root-leaves, which lie 

 spread on the ground in a circle round the central flower- 

 stalk. Each leaf is composed of a flattened petiole and 

 a broad lamina on either side of the midrib. The edge 

 is fringed with teeth, and near the midrib are six bristle-like 

 hairs, three on either side. When one or more of these 

 hairs is touched the two lobes of the lamina close together 

 fairly rapidly and open again in a few minutes. If a fly 

 or any nitrogenous body causes the irritation the leaf 

 remains closed for a week or longer, until the juices of 

 the insect become thoroughly absorbed. 



The Sundews {Droseras) are carnivorous plants, usually 

 growing in peat bogs, either in sheltered lowlands or moor- 

 lands at a fairly high level. 



The plant called the Round-Leaved Sundew must be 

 well known from the frequency with which it appears on 

 the pages of every book treating of plant wonders, if, 

 indeed, the rosettes of green leaves covered with glistening 

 crimson hairs or tentacles are not already familiar to most 

 of us in its native bogs. Here is a plant which lays itself 

 out for the capture of insects in a fashion resembling the 

 Dion<za, but where the movement of the whole leaf is 

 replaced by the movement of the tentacles only, the leaf 

 becoming curled up slightly by reason of the bending of 

 the tentacles. But it is only a nitrogenous body which 

 causes the glands to secrete their viscid fluid, bending over 

 the unhappy victim. The sensitive area is strictly confined 

 to the gland on the apex of each tentacle, and the case is 

 one of entirely chemical stimulus. 



The Butterwort is yet another British plant whose 

 nervous system is irritable, being affected in the same 

 manner as the sundew, the edges of the leaves rolling 



