OR APPENDAGES OF PLANTS. 181 



plant a mere variety of S. viridis, t. 19, all whose 

 bracteas are green and fertile. Bartsia, alpina, Engl, 

 Bot, t. 361, and Melampyrum arvense, t. 53, display 

 an elegant transition from leaves to coloured bracteas. 

 The Orchis tribe have green leafy bracteas, different 

 in size in different species. A most beautiful large 

 and coloured bractea is produced in Musscetida Jron- 

 dosa, Hort. Mai, v. 2, t. 18, from one of the teeth of 

 the calyx, also in M. glabra of Willdenow, and two 

 new species brought from America by Mr. John Fra- 

 ser. Spinous bracteas of a curious construction guard 

 the calyx in Atractylis cancellata^ f. 119. Linnaeus 

 observes that no bracteas are to be found in the class 

 Tetradynamia. 



The ochrea of Rottboll, Willdenow's Principles of 

 Botany^ 50, which enfolds the flower-stalks in Cype- 

 rus, see Engl. Bot. t. 1309, seems to me a species of 

 bractea. 



3. Spina, f. 120. A Thorn. This proceeds from the 

 wood itself, and is either terminal like Hlppophae 

 rhamnoides, Engl. Bot. t. 425, Rhamnus catharticuSy 

 t. 1629 ; or lateral as Crattsgus (or Mespilus) Crus- 

 galli, (87) tomentosa, parvijblia, &c. 



Linnaeus observes that this sometimes disappears 

 by culture, as in the Pear-tree, Pyrus sativus which 

 when wild has strong thorns ; hence he denominates 

 such cultivated plants tamed, or deprived of their nat- 

 ural ferocity. Professor Willdenow, Principles of 



(87) f A very common species of thorn .] 



