Solanaceae Source

A global taxonomic resource for the nightshade family

Solanum stenophyllidium

Citation author: 
Bitter
Citation: 
Repert. Spec. Nov. Regni Veg. 12: 51. 1913.
Type: 
Mexico. Jalisco: Río Blanco near Guadalajara, 17 Sep 1886, E. Palmer 611 (holotype: G! [Correll neg. 809: BM!, F!, GH!, K!, LL!, NY!, US!], [drawing: K!]; isotypes: BM! [photo: U!], GH! [Correll neg. 199: BM!, F!, GH!, K!, LL!, NY, US!], NY!, U! [Correll neg. 136: BM!, F!, GH!, K!, LL!, NY!, US!], US-42679 [US neg. 1964: F!, GH!, MICH!, NY!, PTIS!, US!]).
Last edited by: 
Spooner, D.M.
Written by: 
Spooner, D.M.
Habit: 
Herbaceous tuber-bearing perennials 0.25-0.8 m tall. Stems 2-5 mm in diameter at base of plant.
Sympodial structure: 
Sympodial units typically 3-6-foliate.
Leaves: 
Pseudostipules to 6-23 mm long, lunate. Leaves odd-pinnate, (4-) 7-25 cm long, 5-12.5 cm wide, subglabrous to deeply puberulent adaxially and abaxially; petioles 1.5-5 cm long; lateral leaflet pairs (1-) 2 (-3), the size of the lateral leaflets diminishing abruptly towards the base of the leaf; most distal lateral leaflets 2-9 cm long, 0.4-1.7 cm wide, linear to linear-lanceolate, apex acute, base oblique, sessile, decurrent on the rachis; terminal leaflet 4-13 cm long, 0.6-1.8 cm wide, linear to linear-lanceolate, apex acute, base cuneate, occasionally forming a trilobes structure with the most distal lateral leaflets; interjected leaflets absent.
Inflorescences: 
Inflorescence a dichasially branched, ebracteate, monochasial or dichasial cyme, 2-3 forked, generally in the distal half of the plant, with 4-17 flowers, all flowers perfect, peduncle 0.7-6 cm long; pedicels 7-28 mm long, articulate between the proximal ¼ and the distal ¼.
Flowers: 
Flowers with the calyx 4-7 mm long, lobes oblong, acute to apiculate, acumens up to 1 mm long. Corollas 1.2-2 cm in diameter, stellate, without acumens, edges of corolla flat, not folded dorsally, white, with tones of violet on the abaxial side of the lobe tips. Anthers 4-6.5 mm long, connate, yellow, apically poricidally dehiscent and often maturing to a short introrse apical slit, filaments 1-4 mm long. Ovary with style 10-11 mm long, exceeding stamens by 2 mm, straight, with stigma globose.
Fruits: 
Fruits 0.8-1.1 cm in diameter, globose, with dark green stripes.
Seeds: 
Seeds from living specimens green-white throughout, ovoid, ca. 2 mm long, with a thick covering of “hair-like” lateral walls of the testal cells that make the seeds mucilaginous when wet. Removal of these hair-like lateral walls by enzyme digestion reveals a honeycomb pattern at their base.
Chromosome number: 

2n = ploidy missing =24 voucher missing = (Spooner & Hijmans 2001)

Distribution: 

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.

Phenology: 
Flowering and fruiting July through September.
Phylogeny: 

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.

Commentary: 

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.

References: 

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.

Genetics: 

Chloroplast DNA restriction site data available in: Spooner and Sytsma (1992). AFLP, morphological, and microsatellite data listed in: Lara-Cabrera (2001).

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Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith