786 MISC. PUBLICATION 42 3, U. S. DEPT. OF AGRICULTURE 



109. SOLANACEAE. 34 Potato family 



Plants herbaceous or shrubby; leaves usually alternate; flowers in 

 umbels, cymes, or panicles, or solitary and lateral, perfect, regular, 

 the parts in 4's or 5's (rarely in 6's) ; ovary superior, usually 2-celled; 

 fruit a berry or a capsule. 



This large family comprises numerous economically important 

 plants, such as the potato (Solarium tuberosum) , eggplant (S. melon- 

 gena), tomato (Lycopersicum esculentum), redpepper (Capsicum 

 spp.), and tobacco (Nicotiana tabacum), as well as a number of very 

 poisonous species, among them henbane (Hyoscyamus niger) and 

 belladonna (Atropa belladona), sources of the powerful drugs hyoscy- 

 amine and atropine, respectively. Many species in the genera 

 Solarium, Nicotiana, Petunia, and others are grown as ornamentals. 



Tomato plants (Lycopersicum esculentum) are found occasionally 

 growing wild (e. g., at Paradise, Cochise County, Blumer 2266). But 

 there is no evidence that this species has become established any- 

 where in the State, and therefore it is not regarded as a member of 

 the flora. 



Key to the genera 



1. Fruit a dry capsule, dehiscent by valves or, if bursting irregularly, then the 

 capsule large and spiny (2) . 

 2. Flowers solitary in the forks of the stem; corolla broadly funnelform or 

 trumpet-shaped. 4 cm. long or longer, white or pale violet; capsules very 

 large, usually spiny, regularly dehiscent or bursting irregularly. 



8. Datura. 



2. Flowers in terminal inflorescences or, if solitary in the leaf axils, then the 



corolla less than 1 cm. long; capsules small, not spiny, regularly dehiscent 



(3). 



3. Flowers in terminal racemes or panicles; corolla more than 1 cm. long, 



white, greenish, or yellow 9. Nicotiana. 



3. Flowers axillary, solitary; corolla less than 1 cm. long, the limb purple; 

 stems prostrate, forming mats; leaves oblanceolate or spatulate, not 



more than 2 cm. long 10. Petunia. 



1. Fruit berrylike, indehiscent, commonly fleshy but (in genus Lycium) some- 

 times dry and bony (4). 

 4. Plants spiny shrubs; flowers axillary, solitary or in very few-flowered fas- 

 cicles; calyx scarcely enlarged in fruit; corolla campanulate, funnelform, 



or salverform; fruit commonly juicy when ripe 1. Lycium. 



4. Plants mostly herbaceous or suffrutescent, if shrubby then not spiny, if 

 spiny then herbaceous (5). 

 5. Anthers opening by terminal pores or slits, not dehiscent throughout; 

 plants sometimes spiny; inflorescence terminal or extra-axillary. 



7. SOLANUM. 



5. Anthers completely dehiscent longitudinally; plants not spiny; inflores- 

 cence axillary (6). 

 6. Calyx thick, unaltered in fruit, truncate ; berry pungent- - 6. Capsicum. 

 6. Calyx papery, accrescent in fruit, obviously toothed; berry not pungent 

 (7). 

 7. Flowers in a sessile or pedunculate umbel; calyx saucer-shaped at 



maturity, not at all enclosing the fruit 5. Saracha. 



7. Flowers solitary; calyx enclosing the fruit at maturity (8^. 



8. Corolla urceolate 2. M argaranthus. 



8. Corolla rotate to f unnelf orm-campanulate (9) . 



9. Calyx in fruit not angled, the lobes not connivent, leaving the 



top of the berry exposed 3. Chamaesaracha. 



9. Calyx in fruit angled, the lobes connivent over the berry. 



4. Physalis. 



34 Prepared in collaboration with C. V. Morton, Smithsonian Institution. 



