In Queensland, Solanum stenopterum extends from Gayndah to Moonie, and west to Glenmorgan and Yuleba, and there is an old collection from Ashford in New South Wales. It inhabits grassland, Belah forest or Eucalyptus populnea woodland, on clayey soil.
Solanum stenopterum is a typical member of Solanum subgenus Leptostemonum. It is placed into the S. hystrix group (Group 25) by Bean (2004) on morphological grounds; its phylogenetic position has not been investigated using molecular data.
Solanum stenopterum differs from S. lacunarium by the more sparsely distributed, longer and more acicular prickles; smaller leaf lobing index (sometimes entire); stellae very sparse to moderate on lower leaf surface (vs. very dense for S. lacunarium); stellae consistently with 3-5 lateral rays on upper leaf surface (vs. 7-10 lateral rays for S. lacunarium); central ray relatively long; inflorescences comprising 1-3 flowers and common peduncle usually absent (vs. 5-7 flowers, common peduncle 26-46 mm long for S. lacunarium).
In S. stenopterum, the style extends further beyond the anthers than in most other species. It very rarely sets fruit (pers. obs.; I. Menkins pers. comm.). Only 2 fruits are present in the collections at BRI, and both of these are insect damaged.
Conservation status: Currently listed as “Vulnerable” under the Queensland Nature Conservation Act, 1992.
Solanum stenopterum is known from 5 locations, none of which is protected within a conservation reserve. It is threatened by land clearance, agricultural practices, weed encroachment, and mowing of road reserves, where most of the existing stands are located. Applying the IUCN guidelines (IUCN, 2001), a category of “Endangered” is recommended (EN A3ce; B2ab(ii,iii,v)).
Etymology: From the Greek stenos meaning ‘narrow’ and pteron meaning ‘wing’. This is in reference to the proximal extension of the leaf lamina resulting in a winged petiole.
IUCN Species Survival Commision 2001. IUCN Red List Categories and Criteria: Version 3.1.
Gland, Switzerland and Cambridge, UK: IUCN.
Bean, A.R. 2004. The taxonomy and ecology of Solanum subg. Leptostemonum (Dunal) Bitter (Solanaceae) in Queensland and far north-eastern New South Wales.
Austrobaileya 6 (4): 639-816.