LECT. XI.] CAULINAR AND FOLIAR APPENDAGES. 657 



There are two varieties of vegetable claws, the 

 cirrhal and the radicular. 



1. The cirrhal claw (clavicula cirri for mis ) 

 resembles the branched tendril, except that each 

 of the branches is terminated by a small fleshy 

 knob ; which spreading out in the shape of an 

 oval disk, adheres strongly to a wall or any flat 

 surface with which it comes in contact. In the 

 Virginian creeper, Cissus hederacea, the claw, 

 which is of this description, is opposite to the 

 leaf, like the tendril of the Vine, and is spiral in 

 its branches, so that it performs a double office, 

 acting sometimes as a tendril by twining round 

 slender cylindrical bodies, but more frequently as 

 a claw. The internal or anatomical structure of 

 this species of claw, as far as regards its stalk and 

 branches, is exactly the same as that of the ten- 

 dril, and, like it, originates from the alburnum of 

 the stem : the claw itself consists chiefly of cel- 

 lular matter, which, being a continuation of the 

 pith of the other parts of the organ, is here 

 checked in its extension and swells out laterally. 

 The under part of the claw is covered with 

 scarcely any cutis. 



Three theories exist with regard to the mode 

 by which this organ adheres to smooth surfaces : 

 some writers adopting the opinion of Malpighi, 

 that it is produced by a viscous fluid, which is fur- 

 nished by small papillae on the under surface of 

 VOL. i. u u 



