Solanum subinermelooks similar to Solanum junctum and Solanum poinsettiifolium. S. subinerme has larger flowers, longer cauline prickles, and often has long straight prickles on the adaxial leaf surface that are lacking in Solanum junctum. Solanum poinsettiifolium has fewer spines, dense white tomentum on the abaxial leaf surfaces, stout unbranched inflorescences, and more extensive interpetalar corolla tissue than Solanum junctum.