APPENDAGES TO PLANTS, 



In this drawing (Fig. 44V you will observe the thorn (a) to 

 remain on the stem, while the bark (b) has been peeled off. In 

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

 The thorns in some plants have been known to disappear by 

 cultivation. The gr.eat Linnseus imagined that in such cases, 

 the trees were divested of their natural ferocity and became 

 tame. You may smile at such a strange idea, but even great 

 minds have their weaknesses ; when persons become enthusias- 

 tic in any science, they are in danger of fancying analogies or 

 msomblances, which exist only in their own minds. A more 

 rational opinion is given by another botanist, viz. that thorns 

 are in reality buds, which a more favourable situation converts 

 into luxuriant branches. But in some cases they do not disap- 

 pear even under circumstances favourable to vegetation. 

 Thorns have been compared to the horns of animals. 



4th. 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, some- 

 times, they occur in the substance of leaves ; as in the lemon 

 and myrtle, causing them to appear dotted when held to the 

 light. They are found on the petioles of the passion flower, 

 and between the teeth or notches of the leaves of many plants. 



5th. Stings are hair-like substances, causing pain by an acrid 

 liquor, which is discharged upon their being compressed ; they 

 are hollow, slender, and pointed, as in the nettle. 



6th. Scales are substances, in some respects resembling the 

 coarse scales of a fish ; they are often green, sometimes colour, 

 ed, and are found upon all parts of vegetables, upon the roots 

 -of bulbous plants, and upon the stems and branches of other 

 plants. They are imbricated upon the calyxes of most of the 

 compound flowers. You have seen in buds, how. important the 

 scales are to protect the embryo plant during the winter. Ca- 

 lyxes surround the flowers of grasses, under the name of glumes. 

 Scales envelope and sustain the stamens and fruit of the pine, 

 oak, chesnut, &c. 



Thorns in some cases made to disappear Glands Stings Scales. 



