Solanum dimidiatum

Western Horse Nettle is an introduced herbaceous perennial in the Nightshade Family (SOLANACEAE). It is native to the central United States (Texas, Oklahoma, and Kansas), but has been introduced in many other locations. In Alabama, it is found in the southeastern portion of the state. Western Horse Nettle grows in fields, in pastures, on roadsides, and along railroads. It is a perennial with elongate rhizomes. It often forms colonies. Stems are 1-2 feet in height, branched above the middle, green in color, pubescent with stellate hairs, and armed with prickles. Leaves are alternate, petiolate, ovate to lanceolate in outline, irregularly lobed, and pubescent with stellate hairs. The leaves may be armed with prickles along the midrib of the lower surface of the leaf. Flowers are produced in axillary and terminal racemes. The corolla is 5 parted, the lobes spreading. The corolla is blue in color. The anthers are erect and connivant (converging and touching but not fused). The pollen is released through pores at the tips of the anthers. The fruit is a many-seeded berry. The fruit turns yellow when it is mature. Western Horse Nettle is listed as an invasive species in California and Australia. Western Horse Nettle is somewhat similar to our native Carolina Horse Nettle (Solanum carolinense Linnaeus). It differs by having stellate trichomes on the lower leaf surface with 6-8 equal rays, generally being a larger plant, and by having blue flowers. Carolina Horse Nettle has stellate trichomes of the lower leaf surface with 2-5 rays, the central one elongate, and usually white or pale blue flowers.--A. Diamond

Some authors have separated Solanum perplexum Small from S. dimidiatum Raf. based on a suite of characters including size of stellate hairs, corolla, and calyx.  When separated, S. perplexum would represent the Alabama material along with Georgia and Florida with S. dimidiatum occurring to our west in Texas and other states.  In examining material from Texas compared with the Alabama specimens, these characters are seemingly variable thus  not reliable enough to discern the two taxa.--B.R. Keener