242 STUDY OF COMMON PLANTS. 



The Solanacese include over twelve hundred species, 

 chiefly tropical and sub-tropical, some representatives, 

 however, being widely cultivated in temperate regions. 

 Many of them possess strongly narcotic and poisonous 

 properties, as the names deadly nightshade, henbane, etc., 

 indicate. A few are much employed in medicine. The 

 potato is the most useful, the tobacco plant the most 

 harmful member of the family. Morphologically this 

 group of plants is of interest in its affinities, more or less 

 distinctly marked, with several conspicuous families, the 

 Scrophulariacese and Convolvulacese among them. Physi- 

 ologically it offers comparatively little of special impor- 

 tance, although some species exhibit interesting adaptations 

 for insuring fertilization. 



SPECIAL STUDIES. 



I. Morphology of fruits and seeds of the Solanaceae. 



II. History of the common potato and a study of its 

 varieties. 



III. Affinities of the Solanacese, and how they are deter- 



mined. 



IV. Identification of the narcotic species by means of 



their epidermal appendages. Microscopical ex- 

 amination of commercial specimens of hyoscy- 

 amus, tobacco, etc. 



