BARTLETT. — THE PURPLE-FLOWERED ANDROCERAE. 627 



VII. THE PURPLE-FLOWERED ANDROCERAE OF MEXICO 

 AND THE SOUTHERN UNITED STATES. 



By Harley Harris Bartlett. 



The Mexican Solanums of the sub-genus Androcera divide naturally 

 into two sections, one of which is characterized by purple or white 

 flowers and the lack of stellate pubescence except on the leaves, the 

 other by yellow flowers and extreme development of stellate pubes- 

 cence on all parts of the plant. In the only apparent exception to 

 this grouping, Solarium macroscolum Fernald, the flowers are tinged 

 with purple, but the basal color, over which the purple is suffused, is 

 yellow. The pubescence is that of the second section, to which the 

 plant evidently belongs. All of the species of the first section, with 

 the single exception of S. Grayi Rose, which has white flowers, are 

 purple-flowered. Those in the Gray Herbarium may be determined by 

 the following key : 



Anthers of two kinds ; four subequal and straight, the fifth longer and curved. 

 Corolla 1 cm. long or less. 



Pubescence and spines of young fruiting calyx olive-green. 



<S. heterodoxum. 

 Pubescence and spines of young fruiting calyx golden-brown. 



S. heterodoxum var. novomexicanum. 

 Corolla about 2 cm. long. 



Pedicels stout, about as long as the fruiting calyx. 



Spines on stem scattered, separated from one another by their own 



length S. citrullifolium. 



Stem densely bristly with slightly refiexed spines. 



S. citrullifolium var. setigerum. 



Pedicels slender, longer than fruiting calyx S. tenuipes. 



Anthers of three kinds, two short and straight, two longer and curved, form- 

 ing a transition to the still longer arid more curved fifth. 



S. Lumholtzianum. 



Solanum heterodoxum Duval. Caulis sparsim vel deDse aculea- 

 tus, pilosus vel in parte inferiore subglaber, pilis apice gland uliferis. 

 Folia petiolata sub-bipinnatifida, partibus 5-7 oppositis, utrinque 

 aculeata, supra glabra vel pilis paucis simplicibus conspersa, subtus 

 et pilis stellatis et simplicibus tecta. Pedunculus 3-5 cm. longus. 

 Pedicelli 8-12 mm. longi crassiusculi aculeati glanduloso-pilosi. Flores 



