OR APPENDAGES OF PLANTS. 183 



pound, SO that the chances of their meeting with a 

 support are multiplied. (88) The Vine, Fitis v'mifera^ 

 the various species of Passion-flower, and the Pea or 

 Vetch tribe afford good examples of spiral tendrils^ 

 The Virginian Creeper Hedera^ or, as it ought to be 

 called, Vitis quinquefolia, has branched tendrils, whose 

 extremities adhere to the smoothest flint, like the 

 fibres of Ivy. Gloriosa superba^f. 76, Andr. Repos. 

 t. 129, and Flagellaria indica^ have a simple spiraj 

 tendril at the end of each leaf ; for they belong to the 

 Monocotyledones, the structure of whose whole her- 

 bage is generally of the most simple and compendious 



(88) [This is commonly the case with such tendrils as fasten 

 their extremities, and then contract tliemselves into a spiral 

 Gdil, thus drawing the plant nearer to the supporting object' 

 The circumstance of the turns being made in opposite direc- 

 tions, is clearly a provision to obviate the twisting of the tendrils 

 which would otherVvise take place. 



Mr. Knight has published, in the Philosophical Transactions 

 for 1812, some experiments, which go to illustrate the laws of 

 the motions of tendrils. A number of trials, made with terjdrils 

 of the Vine, Ivy, 8cc. shewed that these organs recede from the 

 light, and tend toward shady or opake bodies in their neigh- 

 bourhood. A plant of the Amfielofisis quinqurfolia which was pla- 

 ced in the middle of a greenhouse, pointed its tendrils toward 

 the north or back wall. Another plant of the same species be- 

 ing placed at the east end of the house, presented its tendrils to- 

 ward the west or centre of the house. Being transferred to the 

 west end and exposed to the evening sun, the tendrils turned 

 round, and pointed again to the centre of the house. In another 

 case the tendrils were sensibly attracted by a piece of dark col- 

 oured paper placed near them, while a pane of glass did not pro- 

 duce on them the least effect.] 



