Oil. X.] APPENDAGES TO PLANTS. fli 



found upon the leaf or the calyx, and in some instances upon the 

 berry j as in the Gooseberry. 



Pig. 39. 



a, 



243. Thorns, seem to be a kind of short pointed stem, easily 

 distinguished from prickles, as they grow from the woody part 

 of the plant, while the prickle proceeds only from the bark. On 

 stripping the bark from a rose-bush, the prickles Will come away 

 with it. but let the same experiment be made with a thorn busli, 

 and although the bark may be sepal ated, the thorn will still re- 

 main projecting from the wood. 



244. In this drawing (Fig. 39) you will observe the thorn (a) 

 to remain on the stem, while the bark (b) has bee'n peeled off. 

 In the prickle (c) the whole appears separated from the plant 

 Thorns in some plants have been known to disappear by culti- 

 vation. The great Linnaeus imagined that the trees wefo -di- 

 vested of their natural ferocity and became tame. A more ra- 

 tional opinion is given by another botanist., viz.: that thorns are 

 in reality buds, which a more favourable f-Usiation converts into 

 luxuriant branches. But in some cases they do nut disappeai 

 even under circumstances favourable to vegetation. Thorns 

 have been compared to the horns of animals. 



245. Glands are roundish, minute appendages, sometimes 

 called tumours or swellings; they contain a liquid secretion, 

 which is supposed to give -to many plants their fragrance. 

 They are sometimes attached to the base of the leaf, sometimes 

 fhey occur in the substance of leaves ; as in the Lemon and 

 Myrtle, causing them to appear dotted when held to the li^ht. 

 They are found on the petioles of many plants, and between 

 ilie teeth or notches of many others. 



246. Stings are hair-like substances, causing pain by an 

 acrid liquor, which is discharged upon tneir being compressed; 

 they are hollow, slender, and pointed, as in the Nettle. 



247. Scales are substances in some respects resembling the 



243. What are thorns? 



244. What does Fig. 39 represent! 



245. What are glands'? 

 240. What are stints ? 

 847. What are scale*? 



