50 



ARMATURE. 



Fig. 91. 



Thorn, (spine,) Fig. 90. This is a well Fi ^ - 90 

 known and sometimes very troublesome ap- 

 pendage. It originates in the wood of the 

 plant, with which it forms a part. It is some- 

 times found on large trees, as the Honey-locust, 

 (Gleditschia,) but is more common on shrubs, 

 as the common Thorn bush. In some species, 

 this part disappears by culture, as in the Pear 

 tree. Hence Linnaeus denominates such plants as tamed, or 

 deprived of their natural ferocity. 



Prickle, (Aculeus,) Fig. 91. This part arises 

 from the bark only, as in the Rose and Briar, and 

 does not disappear by cultivation. If the Bark be 

 stripped from the Rose stem, the prickles come 

 off with it, but if stripped from the Thorn bush, 

 the thorns will remain attached to the wood ; a 

 proof that thorns are attached to the wood, and 

 prickles to the bark. 



Tendril, (clasper,) Fig. 92. This is the true 

 fulcrum, or support of many plants, being de- 

 signed to sustain weak and climbing stems, 

 which have not sufficient strength to support 

 themselves. The tendril proceeds either from 

 the side of the stem, as in the Gourd, from the 

 end of the leaf, as in the Gloriosa superba. 

 or sometimes from the end of the flower stalk. 



The tendrils of the Gourd, and of most other plants, are at 

 first straight, and appear to reach forward for the purpose of 

 finding some support on which to lay hold. After having 

 taken hold of some support, they soon make several turns 

 around it, and then coil themselves into the form of a spiral 

 spring, so that when the wind blows they have an elastic at- 

 tachment, which often prevents their being torn from their 

 places. The tendrils of the Gourd will remain straight and 

 reaching for several days, unless they sooner find something 

 to entwine themselves around : while if a twig be placed 

 within their reach, they will make several turns around it in 

 as many hours. Few plants exhibit the uses or beauty of 

 this part so strikingly as the common Gourd. In some 



Does the thorn originate in the wood, or in the bark ? How does the 

 prickle differ from the thorn ? What is the use of the tendril, or clasper ? 

 From what parts of the plant do the tendrils proceed ? What plant is 

 mentioned as showing in a peculiar manner the use and beauty of the 

 tendril ? 



