CHAPTER XXXII. 

 SOLANAGE.^. 



1. General Characters of the Order. Herbs or shrubs. 

 Leaves usually alternate, exstipulate. Flowers generally regular, 

 hypogynous. Calyx, inferior gamosepalous, 5-fid, persistent. 

 Corolla hypogynous, gamopetalous, 5-lobed, usually campanu- 

 late or salver-shaped. 



Androecium of 5 epipetalous stamens. Gynaecium syncarpous, 

 2 carpels ; ovary usually 2-celled with many ovules on a thick 

 axile placenta. Fruit a capsule or berry ; seed endospermous. 



An extensive Order of plants, chiefly found in the tropics and 

 especially in South America. Poisonous alkaloids occur in 

 many plants belonging to the Order. 



The genus Solanum, from which the Order is named, embraces 

 about 800 or 900 species, many of them ornamental plants. 

 Only five or six species bear tubers, the chief being the common 

 potato. 



2. Potato (Solanum tuberosum L.). — Introduced into Europe 

 in the sixteenth century, first to Italy and Spain, and independ- 

 ently into the British Isles a little later in the same century. 



Seed and seedling. — The albuminous seed germinates readily 

 and produces a young seedling with well-marked primary root 

 and two ovate cotyledons (4, Fig. 138). The plumule develops 

 into an upright stem with leaves, and from the axils of the coty- 

 ledons, whose petioles lengthen considerably, shoots arise which 

 are positively geotropic (Fig. 140). These shoots soon find their 

 way into the ground, and after the growth of two or three inter- 

 nodes their tips become tuberous through the deposition within 

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