Rediscovery and taxonomic placement of Solanum polyphyllum Phil. (Solanaceae), a narrow endemic from the Chilean Atacama Desert

Abstract

Although the original description of Solanum polyphyllum Phil. was made in 1891, this species was not seen until it was re-discovered 128 years later in 2019 in the Atacama Desert. Fruits and seeds were previously unknown and a complete description is provided here. This species was not treated in the most recent monograph of Solanum sect. Regmandra , but it should be incorporated in this section due to its glabrous, sessile and entire leaves, which are decurrent onto the stem. Morphologically, S. polyphyllum is similar to S. paposanum , also of section Regmandra , but differs in the entire leaves (against margins with 4–5 acute lobes in S. paposanum ) and glabrous leaves (moderately pubescent adaxially and velutinous abaxially in S. paposanum ). The rediscovery of S. polyphyllum at a new locality at the same altitudinal belt as the type, re-affirms its restricted distribution and endemism and supports a potential conservation status as an endangered species.