Y2 KEY TO THE SPECIES 



2. Fhysalis. Calyx becoming much enlarged and inclosing the fruit ; an- 

 thers unconnected. 



* * Fruit a dry pod ; corolla funnel-form. 



3. Datura. Calyx tubular-prismatic, 5-toothed. 



1. SOLANUM (Nightshade) 



Herbs or shrubs with wheel-shaped corolla, protruding anthers converging 

 around the style and opening by terminal pores, and fruit a berry. (See Plant 

 Relations, p. 26, Fig. 21 ; also Plant Structures, p. 198, Fig. I67a.) 



* Not at all prickly ; anthers blunt. 



-I- Low and generally spreading ; cymes 3-3 flowered. 



1. Solanum triflorum Nutt. (Cut-leaved Nightshade). Nearly glabrous, 

 branched and, more or less spreading ; leaves oblong, pinnately lobed, the sinuses 

 deep and rounded ; corolla white, small, nodding, longer than the 5-parted calyx ; 

 berry green, 8-10 mm. in diameter. Abundant in waste ground and on the plains. 



-J- -1- Erect herbs, 



2. Solanum nigrum (Common Nightshade). Low, much branched and 

 spreading, nearly smooth ; leaves ovate, wavy-toothed ; flowers white, in small 

 umbel-like lateral clusters ; berries globular, black. Commonly Introduced in 

 waste grounds. 



3. Solanum tuberosum (Potato). Erect ; leaves pinnate, of several ovate 

 leaflets with minute ones intermixed ; flowers blue or white ; berries globular, 

 green. Cultivated from Chili for the tubers. (See Plant Relations, p. 76, Fig. 67.) 



* * Prickly ; anthers acute. . 



4. Solanum rostratum Dunal (Beaked Nightshade). Yellowish-hoary 

 with a dense stellate-pubescence and armed with numerous yellow prickles ; 3-7 

 dm. high ; leaves once or twice pinnatifid ; corolla yellow, 2-3 cm. broad ; stamens 

 dissimilar, the lowest one larger and with an incurved beak ; fruit inclosed by the 

 close-fitting and strikingly spiny calyx. Sandy plains. 



2. PHYSALIS (Ground-cherry) 



Herbs with simple toothed or lobed leaves, mostly solitary axillary drooping 

 flowers, producing large juicy berries inclosed in an inflated reticulate-veined, 

 husk-like calyx. 



* Viscidly glandular pubescent. 



1. Physalis rotundata Rydb. (Rocnd-leaved Ground-cherry). Coarse 

 prostrate or spreading perennials, with numerous, forked, zigzag branches ; leaves 

 cordate-orbicular, somewhat toothed, on short, winged petioles ; corolla greenish- 

 yellow with a brownish center, about 15 mm. broad ; fruiting calyx large, ovoid, 

 and slightly sunken at base. 



* * Pubescence not viscid-glandular. 



2. Physalis lanceolata Michx. (Prairie Ground-cherrt). Glabrous or 

 pubescent with mostly simple hairs; slender, erect, sparingly branched, 1-4 dm. 

 high ; leaves with entire or undulate margin, oblong-ovate to narrowly lanceolate, 

 tapering into the short petiole ; corolla yellowish with a darker center, 12-16 mm. 

 broad ; berry greenish-yellow. Plains and canons. 



