The Natural System of Botany. 331 



Polemonium. Mostly North American herbs. Cultivated as 

 ornamental plants. 



Diapensiacejs. The Diapensia Tribe. Ex: Diapensia, 

 pyxidanthera. Low, shrubby, evergreen trailing plants. 



CoNvoLVULACBiE. The Morning-glory Tribe. An impor- 

 tant order of twining or trailing plants, mostly natives of hoi 

 countries. Jalap is furnished by a Mexican Convolvulus. 

 The Sweet Potato is the tuber of C. Batatus. The Morning- 

 glory and the Bind- weed are other examples. Cuscuta, (Dod- 

 der) and Dichondra, also belong here. 



SolanacejB. The Potato Tribe. A large and very impor- 

 tant order. Ex. : Solanum, (Potato, Tomato, Egg-plant, &c.) 

 Capsicum (Red Pepper), Atropa (Nightshade), Belladonna, 

 Datura, Nicotiana (Tobacco), Hyoscyamus, &c. Properties 

 very discordant ; generally stimulant and narcotic, often vio- 

 lently poisonous. In the eatable species, the deleterious prin- 

 ciple is expelled by cooking or ripening in the sun. 



Gentianace^. The Gentian Tribe. A large Order of 

 herbs, some very ornamental. Ex.: Gentiana, Menyanthes 

 (Buck-bean), Sabbatia, Frasera. A tonic and intensely bitter 

 principle, called Gentianine, is found in all the order. 



ApocynacejE. The Dog's-bane Tribe. Trees, shrubs, and 

 herbs. Ex.: Apocynum (Dog's-bane), Vinca (Periwinkle), 

 Nerium (Oleander). The juice and seeds usually possess poi- 

 sonous properties. Nux vomica is the seed of a species of 

 Strychnos ; Caoutchouc or India-rubber is produced by some. 



AscLEPiADACEiE. The Milk-weed Tribe. Ex. : Ascle- 

 pias (Milk-weed, Butterfly-weed). Properties similar to those 

 of the last, though not so active. 



JasminacejE. The Jessamine Tribe. Ex. : Jasminum 

 (Jessamine). Asiatic shrubs, with showy and fragrant 

 flowers. 



Oleaceve. Trees or shrubs. Ex. : Olea (The Olive), 

 Fraxinus (The Ash), Syringa (The Lilac). In the bark gene- 

 rally resides a bitter, astringent principle. The sweet cathar- 

 tic, Manna, is the gum of a species of Fraxinus ; and Olive oil 

 is pressed from the fruit of Olea Europasa. 



