2n = ploidy missing =24 voucher missing = (Spooner & Hijmans 2001)
Northwestern Mexico (N Chihuahua and Sonora) south along eastern and central Mexico to Michoacán and México; (1100-) 1380-2500 m, cultivated fields, tropical deciduous forests, oak forests, streamsides, savannas, mesquite grasslands, dry rocky hillsides, often in dry sandy rocky soils, or in richer organic soils, in areas of oak, pine, and Acacia forests.
Solanum stenophyllidium belongs to the potato clade of Solanum (Bohs, in press). Spooner and Sytsma (1992) placed S. stenophyllidium and all other North and Central American diploids (exclusive of S. bulbocastanum, S. cardiophyllum, and S. verrucosum) in the basal “clade 1” of section Petota based on chloroplast DNA restriction site data. These Mexican diploids were studied by Spooner and Lara-Cabrera with morphological and microsatellite data (Lara-Cabrera and Spooner, in press a) and AFLP data (Lara-Cabrera and Spooner, in press b). Spooner et al. (2004) placed S. stenophyllidium in the Stenophyllidia group which to also contains the phenetically similar S. ehrenbergii and S. hintonii. They recognized this as a possibly paraphyletic group of convenience until more data were available on interspecific relationships.
Lara-Cabrera, S. & D.M. Spooner Taxonomy of Mexican diploid wild potato (Solanum sect. Petota) species: AFLP data.
Plant Syst. Evol.
Lara-Cabrera, S. & D.M. Spooner Taxonomy of Mexican diploid wild potato (Solanum sect. Petota) species: morphological and microsatellite data.
Monogr. Syst. Bot., Missouri Bot. Gard.
Rydberg, P.A. 1924. The section Tuberarium of the genus Solanum in Mexico and Central America.
Bull. Torrey Bot. Club 51: 145-154; 167-176.
Correll, D.S. 1952. Section Tuberarium of the genus Solanum of North America and Central America.
U.S.D.A. Agric. Monogr. 11: 1-243.
Hawkes, J.G. 1956. A revision of the tuber-bearing Solanums.
Rep. Scott. Pl. Breed. Stn. 1956: 37-109.
Correll, D.S. 1962. The potato and its wild relatives.
Contr. Texas Res. Found., Bot. Stud. 4: 1-606.
Hawkes, J.G. 1963. A revision of the tuber-bearing Solanums. II.
Scott. Pl. Breed. Sta. Rec. 1963: 76-181.
Hawkes, J.G. 1990. The potato: evolution, biodiversity and genetic resources.
Oxford: Belhaven Press.
Spooner, D.M. & K.J. Sytsma 1992. Reexamination of series relationships of Mexican and Central American wild potatoes (Solanum sect. Petota): evidence from chloroplast DNA restriction site variation.
Syst. Bot. 17:432-448.
Spooner, D.M. & R.J. Hijmans 2001. Potato systematics and germplasm collecting, 1989-2000.
Amer. J. Potato Res. 78:237-268; 395.
Lara-Cabrera, S.I. 2001. Taxonomy of Mexican diploid wild potato (Solanum sect. Petota) species: a morphological and molecular study.
Ph.D. Thesis, Plant Breeding and Plant Genetics Program, University of Wisconsin-Madison.
Spooner, D.M., R.G. van den Berg, A. Rodríguez, J. Bamberg, R.J. Hijmans, & S.I. Lara-Cabrera 2004. Wild potatoes (Solanum section Petota; Solanaceae) of North and Central America.
Syst. Bot. Monog. 68: 1-209 + 9 plates.
Bohs, L. 2005. Major clades in Solanum based on ndhF sequences.
Pp. 27-49 in R. C. Keating, V. C. Hollowell, & T. B. Croat (eds.), A festschrift for William G. D’Arcy: the legacy of a taxonomist. Monographs in Systematic Botany from the Missouri Botanical Garden, Vol. 104. Missouri Botanical Garden Press, St. Louis.
Chloroplast DNA restriction site data available in: Spooner and Sytsma (1992). AFLP, morphological, and microsatellite data listed in: Lara-Cabrera (2001).
Solanum stenophyllidium is distinguished from S. jamesii which has pinnatifid pseudostipules (S. stenophyllidium with lunate pseudostipules). It is distinguished from S. cardiophyllum by its white corollas and longer calyx acumens up to 1 mm (cream colored corollas and minute calyx acumens less than 0.5 mm in S. cardiophyllum). It is distinguished from S. ehrenbergii by its leaflets that are linear, linear-lanceolate to lanceolate, with oblique bases (leaflets ovate-lanceolate to lanceolate, bases cordate, oblique or slightly truncate in S. ehrenbergii).
Correll (1962: 280) was unable to locate the type of S. jamesii subsp. nayaritense and proposed the following “lectotype” (correctly a neotype): MEXICO: Nayarit: Tepic, Sierra Madre, near Santa Teresa, 9 Aug 1897, J. N. Rose 2134 (neotype: US-301039! [Correll neg. 137: BM!, GH!, K!, LL!, NY!, UC!, US!]. Spooner et al. (2004) found the holotype at P, invalidating his neotypification.
Rydberg (1924) erred in his new combination Solanum brachistotrichum (correctly ‘brachistotrichium’) (Bitter) Rydberg, as is evident from his incorrect citation of the basionym S. jamesii brachistotrichum Bitter. Hawkes (1990: 79) noted this spelling change but incorrectly justified its maintenance based on established use by Hawkes (1956, 1963) and Correll (1952, 1962). Spooner et al. (2004) restored the correct spelling.
Solanum stenophyllidium exhibits great variation in leaf size, leaflet shape, and indument length and density. Correll (1962) and Hawkes (1990) recognized S. brachistotrichium, S. nayaritense, and S. stenophyllidium as distinct species based on variation of these characters. Lara-Cabrera and Spooner (in press a) could not distinguish S. brachistotrichium from S. stenophyllidium morphologically. Spooner et al. (2004) could not distinguish the above elements with the additional accessions. Living plants of all three elements cultivated under similar conditions at Sturgeon Bay, WI, show a continuous variation.