Solanum triquetrum Cav., 1795

Knapp, Sandra, 2013, A revision of the Dulcamaroid Clade of Solanum L. (Solanaceae), PhytoKeys 22, pp. 1-432 : 258-262

40. Solanum triquetrum Cav. , Icon. Pl. 3: 30, tab. 259. 1795 Figure 97

Solanum lindheimerianum Scheele, Linnaea 21: 766. 1848. Type: United States of America. Texas: Comal County, New Braunfels, Aug 1846, F. Lindheimer s.n. [312/481 III] (holotype: B?, destroyed; lectotype, designated here: MO [MO-3938181]); isolectotypes: BM [BM000934766], F [F-236914], K [K000438659, K000438657], LE, HAL?).

Solanum triquetrum Cav. var. lindheimerianum (Scheele) A.Gray ex Blankinship, Rep. (Annual) Missouri Bot. Gard. 18: 145. 1907. Type: Based on Solanum lindheimerianum Scheele.

Type.

Spain. Cultivated in Madrid, originally from Mexico, Anon. (lectotype, designated by Knapp 2007a, pg. 202: MA [MA-476365]; possible isolectotype: F [F-844667]).

Description.

Semi-woody vine or scrambler with an enlarged woody base, to 2 m long, occasionally an erect subshrub to 0.5 m tall. Stems somewhat angled, glabrous to pubescent with weak simple uniseriate trichomes to 0.5 mm long, these usually ascending and pointing to the distal part of the stems; new growth sparsely to densely pubescent with simple uniseriate trichomes to 0.5 mm long, but usually shorter. Bark of older stems pale greenish yellow. Sympodial units plurifoliate. Leaves simple to basally lobed and hastate, (1.1-)1.8-5(+) cm long, (0.3-)1-3.5 cm wide, deltate to hastate, triangular in outline, sometimes linear, slightly fleshy, the upper and lower surfaces pubescent with simple uniseriate trichomes along the margins and on the veins to uniformly pubescent on the veins and lamina, the trichomes to 0.5 mm long, white; primary veins 3-5 pairs, only just visible in dried material, sometimes slightly impressed above; base abruptly truncate to hastate with 2 basal lobes to 1 cm long, these rounded at the tip; margins entire to basally lobed; apex acute to acuminate, the tip sometimes rounded; petioles 0.3-1.2 cm long, glabrous but with a line of simple trichomes adaxially, apparently only sometimes twining. Inflorescences terminal or lateral, 1-3 cm long, usually simple, very occasionally furcate, with 3-6 flowers, glabrous to pubescent like the stems, the pubescence like that of the rest of the plant; peduncle 0.3-1 cm long; pedicels 0.6-1.2 cm long, ca. 0.5 mm in diameter at the base, ca. 1 mm in diameter at the apex, slender, sometimes tinged purple, glabrous to sparsely pubescent with simple uniseriate white trichomes, articulated at the base from a short sleeve 0.5-1 mm deep; pedicel scars irregularly spaced 1-4 mm apart. Buds when young globose, later ellipsoid, the corolla strongly exserted from the calyx tube before anthesis. Flowers all perfect, usually 5-merous. Calyx tube 1-1.5 mm long, conical, the lobes 1.5-2 mm long, triangular with the tips often long-acuminate, often purplish tinged, glabrous to sparsely pubescent abaxially, densely papillate adaxially, pubescent with simple trichomes to 0.2 mm on internal surface of tips. Corolla 1.5-1.9 cm in diameter, white or tinged with purple, often with a shiny green or greenish white eye, stellate, lobed nearly to the base, the lobes 0.8-0.9 mm long, ca. 0.3 cm wide, reflexed at anthesis, the midvein often tinged purple, glabrous to sparsely pubescent abaxially especially along the distal margins and tips, glabrous adaxially. Filament tube minute, the free portion of the filaments ca. 1 mm long, glabrous; anthers 3.5-4 mm long, 1-1.5 mm wide, ellipsoid, loosely connivent, poricidal at the tips the pores lengthening to slits with age. Ovary glabrous; style 6-8 mm long, glabrous; stigma capitate to somewhat clavate, the surface minutely papillose. Fruit a globose to slightly ellipsoid berry, to 1.5 cm in diameter, bright red when ripe, the pericarp thin and shiny, glabrous; fruiting pedicels 1-1.5 cm, ca. 1 mm in diameter at the base, somewhat woody, deflexed or spreading. Seeds (2-)6-10 per berry, ca. 4 mm long, 2.5 mm wide, flat tened to thickened reniform, reddish brown, the surfaces minutely pitted, in mature fruits the lateral testal cell walls exposed and the seed prominently silky, the testal cells rectangular to slightly sinuate. Chromosome number: not known.

Distribution

( Figure 98 ). In the USA in central, south and west Texas and northern Mexico, south to the state of Coahuila, from sea level to 500 m elevation.

Ecology.

On slopes and in thickets; often growing in moist places.

Common names.

USA. Texas: Texas nightshade (http://plants.usda.gov/java/profile?symbol=SOTR2).

Conservation status.

Least Concern (LC); EOO>100,000 km2 (LC) and AOO>10,000 km2 (LC). See Moat (2007) for explanation of measurements.

Discussion.

Solanum triquetrum , like most other members of the Dulcamaroid clade, has incredibly variable leaf morphology. Leaves vary from small, triangular in outline (hence the specific epithet meaning three -angled) and simple to quite deeply lobed at the base to very rarely pinnatifid with two or three pairs of lobes. Leaf size also varies a great deal, perhaps in response to moisture, some specimens with particularly large leaves appear to have been collected in wetter microhabitats. The only species in North America with which Solanum triquetrum could be confused is Solanum dulcamara , an introduced European taxon. Solanum triquetrum differs from Solanum dulcamara in its free anthers, more pointed leaves, strongly angled stems and smaller flowers. Both species have a green “eye”, often with shiny white margins, at the center of the corolla at the base of the stamens. Solanum triquetrum usually has white flowers, while Solanum dulcamara has purple flowers, but white-flowered plants of Solanum dulcamara occur throughout its range, both native and introduced. Like Solanum dulcamara , Solanum triquetrum arises from a subterreanean woody rootstock and may die back in winter or in particularly dry seasons.

Knapp (2007) lectypified Solanum triquetrum with a sheet cultivated at MA; the fragment at F was taken from the MA sheet and is thus an isolectotype. The location of the type of Solanum lindheimerianum is somewhat problematic. Ferdinand Lindheimer and J. J. Roemer collected together in Texas in 1846, and Roemer gave his collections and many duplicates of Lindheimer’s to Scheele, a clergyman from near Hildesheim, Germany. Scheele described many of Lindheimer’s plants before Engelmann and Gray had a chance to do so, and duplicates of these collections were only distributed in the early 20th century ( Blankinship 1907). The location of Scheele’s herbarium and types is not known, but it is likely they were retained by Roemer in Berlin. Fortunately many duplicates of Lindheimer’s Texas collections were distributed by Engelmann and Gray. The sheet from the Engelmann herbarium at MO [MO-3938181] has a label in Lindheimer’s hand with the date "August 1846" and the locality "New Braunfels" and is the logical choice for a lectotype for Solanum lindheimerianum . A BM sheet dated 1846 is clearly a duplicate of that gathering based on its morphology. The numbering of Lindheimer’s collections is of two sorts: 1) Lindheimer’s field collection numbers, and 2) the exsiccatae numbers given after the plants were organized into taxonomic sequence and applied to plants of the “same” species collected on several dates ( Blankinship 1907). Confusion over duplicates can arise when one or the other number is not cited. For Solanum lindheimerianum the exsiccatae number is 481, while Lindheimer’s field collection number is 312. Blankinship (1907: 145) published the combination "S. triquetrum Cav. var. Lindheimerianum Gray", citing Lindheimer 312 (along with other Lindheimer collections) and pointed out that the two taxa were almost certainly synonyms. Asa Gray apparently did not publish this combination formally, but as Blankinship (1907) made explicit reference to Scheele’s publication of Solanum lindheimerianum , the correct citation for the variety is Solanum triquetrum var. lindheimerianum (Scheele) A. Gray ex Blankinship.

Specimens examined.

Mexico. Coahuila: Saltillo, 1400 m, 1 May 1949, Hinton 16775 (GH); Saltillo, sierra E of Saltillo, 1500 m, 26 Sep 1949, Hinton 16855 (GH); San Vicente, along road from San Vicente SW about 7 miles to southern end of Laguna de Jaca, 9 Sep 1940, Johnston & Mueller 1067 (GH); La Ventura, road from state boundary, north to Saltillo (6 mi N of La Ventura), 12 Sep 1938, Johnston 7640 (GH); San Antonio de los Álamos, eastern base of the volcanic Sierra de San Antonio, 20 Aug 1941, Johnston 8259 (GH); Múzquiz, La Mariposa, 5 Dec 1936, Marsh 1032 A (F, GH); Monclova, 5 May 1939, Marsh 1657 (F, GH); La Ventura, 1896, Nelson 3900 (GH, US); Torreon and vicinity, 13 Oct 1898, Palmer 476 (BM, F, G, GH, K, S, UC); Perras, 11.5 miles W of Salsillo, 22 Apr 1880, Palmer 930 (GH, LE, P); Jimulco, 12 May 1885, Pringle 153 (BM, E, F, G, GH, GOET, K, L, LE, US); Sierras Negras, 9 km S of Parras, 2400 m, 3 Jul 1941, Stanford et al. 141 (GH); Toboso, flat 4 km W of San Juan, SW of Sierra de las Cruces, 11 Jul 1941, Stewart 813 (GH); 23 miles SW of Monterrey, 1 Dec 1945, Warnock & Barkley 148 (GH); Saltillo, 70 miles west, 7 Aug 1957, Waterfall & Wallis 13286 (F); Monclova, 609 m, 5 Jul 1939, White 1789 (ECON); Ramos Arizpe, Hacienda La Rosa, 14 Jun 1936, Wynd & Mueller 34 (GH, US); Hidalgo: Zimapán, Douglas 1229 (K); Zimapán, 22 Jun 1947, Kenoyer 1104 (GH); Nuevo León: Monterrey, Acequia Guadelupe, Jul 1911, Arsène 6424 (US); Linares, S of Monterrey on Pan-American highway, 28 Apr 1939, Frye & Frye 2518 (GH, UC, US); Aramberri, La Ascensión, to Sandia, 1800 m, 16 Sep 1890, Hinton 20406 (GH); Galeana, El Peñuelo, 1725 m, 24 Jul 1891, Hinton 21115 (GH); Monterrey, Monterrey, South of I.T.E.S.M. campus, 487 m, 14 Jul 1970, Imboden 39 (EIU); El Carrizo, near Monterrey, 6 Nov 1903, Lozano s.n. (US); Monterrey, 11 Sep 1902, Pringle 11062 (BH, F, GH, GOET, K, US); Mirador, near Monterrey, 1946, Roybal 748 (US); Icamole, mountains near town, 3 Feb 1907, Safford 1253 (US); Monterrey, 11 Oct 1895, Seler & Seler 1070 (GH); Paso de Mamulique, 365 m, 14 Mar 1984, Thompson et al. 1287 (F); San Luis Potosí: sin. loc, 1878, Parry s.n. (GH); Salado, 24 mi. S of Salado, 1692 m, 22 Aug 1940, Shreve & Tinkham 9633 (GH); Tamaulipas: Tigre Crossing, south of crossing, 10 Feb 1939, LeSueur 370 (F); Laguna Anda la Piedra, 14 Feb 1939, LeSueur 427 (F); Mun. San Fernando, San Fernando, northern outskirts, 3 Jan 1981, Nee et al. 19434 (F); Ciudad Victoria, southeastern outskirts of city, 400 m, 22 Oct 1981, Nee 22211 (F); E of Matamoros, 25 Oct 1907, Rose & Russell 24215 (K); Zacatecas: La Pendencia, 8 km NW, 1475 m, 16 Jun 1972, Chiang et al. 7857 (F).

United States of America. New Mexico: sin. loc, 1851, Wright 1591 (F, F, G, GH, K, US); Texas: Bell County: Little River, near Little River, Wolff 395 (US); Belton, 12 Feb 1932, Wolff 3449 (US); Bexar County: San Antonio, 19 Oct 1927, Rose & Rose 24143 (GH, US); Seguin Road, 4 miles east of San Antonio, 14 Aug 1931, Sister Mary Clare s.n. (S); Camden Road near Elmendorf Lake, 4 Apr 1940, Sueltenfuss 174 (BM); Converse, 2 miles N of Converse, 28 Jun 1929, Wolff 975 (US) Brewster County: 9-Point Mesa, summit and upper slopes, on 9-Point Mesa Ranch about 60 miles S of Alpine, 22 Sep 1966, Correll 33801 (GH); Alpine, 22 miles E of Alpine, 2 Jul 1941, Smith T-1197 (US); Altuda Mountain, Glass Mtns, 26 Jun 1940, Warnock 326 (GH); Brookes County: Talfurrias, Salt Lake at Gypsum Mine SE of Talfurrias, 23 Nov 1940, Innes 313 (GH); Brownwood, 30 Oct 1924, Palmer 26758 (A, S); Calhoun County: Port Lavaca, shore of bay, 3 Aug 1946, Gentry 38 (F); East Kararkawa Point, 9 Sep 1922, Tharp 1609 (US); Cameron County: Rio Hondo, Jul 1913, Chandler 7011 (GH, US); Las Palmas Plantation, 4 miles SW of Brownsville, 4 Oct 1952, Correll 14842 (GH); Brownsville, 11 miles NW, 18 Mar 1960, Gentry & Barclay 18420 (US); Brownsville, by Pan American airport, 26 Feb 1939, Muenscher & Muenscher 14443 (GH); Laguna Atoscosa National Wildlife Refuge, Unit 2, N side of Impoundment 2, ca. 100 m W of its intersection with road, 1 m, 24 Apr 1959, Traverse 1098 (F, GH); Chambers County: sin. loc, 7 Apr 1936, Tharp s.n. (GH); Comal County: Comanche Spring: New Braunfels, etc, Jun 1850, Lindheimer 1045 (BM, E, F, G, GH, K, LE, US); New Braunfels, 1 mile west of Landis Park, 21 May 1946, Warnock 46352 (S) Crockett County: Ozona, 11 3/4 miles E of Ozona, 3 Nov 1937, Cory 26624 (GH); Dallas County: Dallas, 27 Oct 1900, Bush 1621 (GH, K, US); Dallas County, Dallas, bottom of Trinity River, Jun 1876, Reverchon s.n. (US); Dallas County, Dallas, Jun 1877, Reverchon 671 (US); Dallas County, Fort Worth, 9 Sep 1877, Ward s.n. (US); De Witt County: Cuero, 22 Mar 1907, Howell 306 (US); Edwards County: Substation #14 Yard, 26 Aug 1940, Cory 35253 (GH); Fort Bend County: Duke, 2 Oct 1914, Palmer 6703 (F, US); Galveston County: field E of road that goes N to “Bob’s Place" from highway 87, 8.7 miles W of Gilchrist, 3 m, 25 May 1961, Traverse 2330 (A); Guadelupe County: Seguin, old Zorn House, 3 Apr 1949, Cory 55414 (US); Hays County: San Marcos, 167 m, 1 Aug 1943, Fisher 43037 (B, US); Hidalgo County: Mission, 10 Nov 1940, Cory 36042 (GH); 12 miles north of Mission, 4 Apr 1941, Lundell & Lundell 9948 (US); Red Gate, 1.5 miles S of Red Gate, along side road to Laguna Seca Historical Marker, just W of Hwy. 281, 22 m, 19 Jan 1981, Nee 20070 (F); McAllen, 18 Dec 1981, Nee 24056 (F, MA); Santa Ana National Wildlife Refuge, 14 Apr 1977, Solomon 2705 (LE); Hudspeth County: Eagle Mountain, E slopes, about 6 miles S of Hot Wells, 7 Jul 1943, Waterfall 4925 (GH); Eagle Mountain, in valley running into Eagle Mountains about 1/4 mile S of the flouride mine, 31 Aug 1945, Waterfall 6278 (GH); Eagle Mountain, slopes between flouride mine and Eagle Peak, 31 Aug 1945, Waterfall 6330 (GH); Kimble County: US routes 183-283, north of Junction, 12 May 1947, McVaugh 8293 (F, G, GH); Maverick County: Eagle Pass, 2 Aug 1931, Clark 4078 (B, G); Normandy, 5 miles N, 10 Sep 1962, Scora 2289 (US); Nueces County: Corpus Christi, 26 Sep 1958, Correll 20405 (GH); Corpus Christi, 5 Mar 1894, Heller 1399 (E, GH, K, LE, US); Pecos County: 13.5 miles E of Fort Stockton along Highway 290, 17 Apr 1965, Correll & Correll 30886 (GH); Presidio County: Crawford Tank, on Holland and Meriwether Ranch, NE side of the Sierra Tierra Vieja, ZH Canyon, Espy Miller Ranch, 1500 m, 7 Sep 1941, Hinckley 2120 (GH); San Patricio County: Portland-Gregory, 17 Mar 1929, Tharp 5608 (US); Welder Wildlife Foundation, 175 m E of Moody’s Camp, 10 m, 4 May 1959, Traverse 1221 (F, GH, US); San Saba County: San Saba, 12 May 1930, Harris 711 (US); Sutton County: Sonora, 7 1/3 miles N of Sonora, 28 Oct 1945, Cory 50553 (GH, US); Tarrant County: Fort Worth, along Trinity River, 31 Oct 1925, Palmer 29476 (GH); Taylor County: Camp Barkeley, 20 Oct 1942, Tolstead 5833 (GH); Terrell County: Spofford, 8 May 1904, Griffiths 6274 (US); Tom Green County: San Angelo, 3 Jul 1916, Palmer 10356 (S, US); Knickerbocker Ranch, Dove Creek, May 1880, Tweedy s.n. (US); along South Concho River near Cristoval, 6 Jul 1933, Wolff 4189 (F); Travis County: Austin, 19 May 1872, Hall 494 (F, GH, US); Austin, near 51st St and Duval, 20 Feb 1995, Nesom & Nesom 7 (F, GH, K, US); Zilker Park, in valley of Braton Creek, ca. 2 mi upstream from Barton Springs, 2.5 mi from Colorado River, ca. 0.5 mi NE of Loop 360 bridge over creek, Barton Creek Greenbelt, 182 m, 31 May 1989, Orzell & Bridges 10186 (S); Valverde County: Goodenough Spring, 15 miles south of Comstock near the Rio Grande, 13 Nov 1964, Correll & Correll 30667 (GH); Del Rio, 289 m, 19 Aug 1932, Fisher 32248 (US); Del Rio, 13 May 1918, Palmer 13590 (B, GH, K, US); Wilson County: Sutherland Springs, Sep 1879, Palmer 929 (GH, K, LE); Zavalla County: Nueces River, 11.5 miles S of Uvalde, 24 Oct 1934, Cory 11954 (GH).

Figures

Figure 97. Solanum triquetrum Cav. (A drawn from Lindheimer 1044 B drawn from Chiang 7857 C drawn from Waterfall 6278 D drawn from Pringle 153 E-H drawn from Burr 452). Illustration by Bobbi Angell.

Figure 98. Distribution of Solanum triquetrum Cav.