EXOGENS. 155 



as a substitute for the Peruvian bark, and the Lirioden- 

 dron tulipifera, or Tulip-tree, etc. 



The Side-saddle family (SARRACENIACE.E) contains 

 the genera Sarracenia and Darlingtonia, which (like Ne- 

 penthes) are characterized by a pitcher-like append- 

 age to the leaf, containing a fluid secretion, supposed 

 to have the power of digesting insects which fall 

 into it. 



CRUCIFER^E, the Cruciferous, or Cress-wort family, 

 known so readily by their four cruciate petals, contains 

 a large number of plants, none of which are poisonous, 

 although some are stimulant and even acrid. Most of 

 the common culinary vegetables belong to this order, as 

 Cabbage, Cauliflower, Turnip, Radish, Cress, and Mus- 

 tard. Many garden flowers also are of this family, as 

 Wallflower and Alyssum. 



The Violet family, (VlOLACE^,) the Mignonette family, 

 (RESEDACE^:,) the Berberry family, (BERBERIDACE^E,) 

 the Rock-Rose family, (ClSTACE^E,) the St. John's-wort 

 family, (HYPERICACE^E,) the Vine family, (VlTACE^E,) 

 the Geranium, or Crane's-bill family, (GERANIACE^E,) the 

 Wood-sorrel family, (OXALIDACE^E,) and many others, 

 must be passed by, since space forbids us to enlarge. 



The Quassia family (SiMARUBACE^E) is noted for the 

 bitter and tonic principle contained in the wood of Quas- 

 sia amara, and other species. 



The Rue family (RUTACE^E) is also known in medi- 

 cine, since it furnishes Rue, Buchu, (Barosma crenata^) 

 and other agents. 



The Flax family (LINAGE^:) furnishes the well-known 

 Flax, (Linum usitatissimum^ whose inner bark yields 



