VARIOUS EXCRESCENCES. 343 



those little animals, chiefly of the Ilymaw- 

 ptera order, and of the genus Cynips^ in 

 some vigorous part of the plant, as the leaves, 

 leaf-stalks, young stem or branches, and 

 sometimes the calyx or germen. The parent 

 insect deposits its egg there, which is soon 

 hatched, and in consequence of the perpetual 

 irritation occasioned by the young maggot, 

 feeding on the juices of the plant, the part 

 where it is lodged acquires a morbid degree 

 of luxuriance, frequently swelling to an im- 

 moderate size, and assuming the most extra- 

 ordinary and whimsical shapes. This often 

 happens to the shrubby species of Hawkweed, 

 Mieracium sabaudim, Engl. Bot« /.349? and 

 vmbellaiiim, t. 1771? whose stems in conse- 

 quence swell into oval knots. Several different 

 kinds of Galls are borne by the Oak, as those 

 light spongy bodies, as big as walnuts, vulgarly 

 named Oak apples ; a red juicy berry-like 

 excrescence on its leaves ; and the very as- 

 tringent Galls brought from the Levant, for 

 the purposes of dyeing and making ink, which 

 last are produced by a different species of 

 Querc >s from either of our own. The com- 

 mon Dog-rose, t. 992, frequently bears large 



