90 LET'I'KU XX\I\-. 



from the midrib to the margin, and bordered with a 

 row of strong, stiff, teeth-like hairs. When young, the 

 two sides of the blade are placed face to face, and the 

 teeth cross each other (jig. 1. a.) ; afterwards, when 

 full grovsTi, the sides spread flat, or nearly so, and the 

 teeth then form a firm spreading border (fig. 6. J. 

 On each half of the blade, stand three delicate almost 

 invisible bristles, uniformly arranged in a triangle. 

 If one of those bristles is touched, the two sides col- 

 lapse with considerable force, the marginal teeth 

 crossing each other, so as to enclose securely any small 

 object which may have caused the irritation, or pressing 

 finnly upon the finger, when the irritation is produced 

 by it ; but wonderful to relate, no other part of the 

 leaf is sensible to external impressions. It is in vain 

 that the back of the leaf is disturbed, or that the 

 smooth glandular surface of the face is irritated; unless 

 you jar one of these bristles no irritability whatever 

 is excited, and the leaf remains immoveably open. 

 The moment the shock is communicated through one 

 of the bristles, the collapse of the leaf is effected, 

 which then assumes altogether the appearance of an 

 iron rabbit-trap when it has closed upon its prey (fig. 

 t. c). If, at this time, an attempt is made to open 

 the leaf, it is violently resisted, in consequence of the 

 rigidity of the side veins, whose contraction seems to be 

 connected with the phenomenon. Upon this subject 

 I shall not dwell any further just now. 



The flowers grow in a cyme at the top of a scape, 

 six or seven inches high. They consist of a calyx of 

 five tooth-letted sepals, five very blunt petals, slightly 



