OF GALLS AND VARIOUS EXCRESCKNCES. 269 



punctures of those little animals, chiefly of the Hymen- 

 optera 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 hatch- 

 ed, and in consequence of the perpetual irritation occa- 

 sioned 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 immod- 

 erate size, and assuming the most extraordinary and 

 whimsical shapes. This often happens to the shrubby 

 species of Hawkweed, Hieraciiim sabaudiim^ Engl. Bot. 

 t. 349, and umhellatum, 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 bod- 

 ies, as big as walnuts, vulgarly named Oak apples ; a 

 red juicy berry-like excrescence on its leaves ; and the 

 very astringent Galls brought from the Levant, for the 

 purposes of dyeing and making ink, which last are pro- 

 duced by a different species of Qiiercus from either of 

 our own. The common Dog-rose, t. 992, frequently 

 bears large moss-like balls, in whose internal parts nume- 

 rous maggots are always to be found, till they become the 

 winged Cynips Rosce^ and eat their way out. Many of 

 our Willows bear round excrescences, (116) as large as 

 peas, on their leaves ; but I remember to have been very 

 much astonished in Provence with a fine branched pro- 

 duction on the Willows in winter, which appeared like a 



(116) [^Very singular spongy or juicy excrescences are produ- 

 ced from some American shrubs of the genus Androvieda and 

 Azalea ; caused, no doubt, bv insects.'] 



