Solanum pilcomayense Morong, Ann. New York Acad. Sci. 7: 177. 1893.

Knapp, Sandra, Saerkinen, Tiina & Barboza, Gloria E., 2023, A revision of the South American species of the Morelloid clade (Solanum L., Solanaceae), PhytoKeys 231, pp. 1-342 : 1

41. Solanum pilcomayense Morong, Ann. New York Acad. Sci. 7: 177. 1893.

Figs 125 , 126

Solanum nigrum L. var. pilcomayense (Morong) Chodat, Bull. Herb. Boissier, sér. 2, 2: 747. 1902. Type. Based on Solanum pilcomayense Morong.

Solanum pilcomayense Morong var. brevipetiolare Chodat, Bull. Herb. Boissier, sér. 2, 2: 811. 1902. Type. Paraguay. "in insula a Caprera [?]" [probably Isla Cabrera in Dpto. Ñeembucu], May 1885-1895, É. Hassler 2524 (lectotype, designated by Morton 1976, pg. 141 [as holotype]: G [G00306739, Morton neg. 8661]).

Solanum nigrum L. forma brevipetiolare (Chodat) Chodat, Bull. Herb. Boissier, sér. 2, 4: 80. 1903. Type. Based on Solanum pilcomayense Morong var. brevipetiolare Chodat.

Solanum nigrum L. subsp. chacoense Hassl., Trab. Mus. Farmacol. 21: 104. 1909. Type. Paraguay. "Gran Chaco, ad ripam occidentalem flum.", T. Rojas in É. Hassler 2324 (lectotype, designated by Morton 1976, pg. 141 [as holotype]: G [G00306755, Morton neg. 8660]; isolectotypes: BM [BM000087562], G [G00306749, G00306750, G00306751, G00306753], GH [00105872], K [K000585693], W [acc. # 1906-0001034]).

Solanum nigrum L. forma floribundum Hassl., Trab. Mus. Farmacol. 21: 104. 1909, as " Solanum nigrum L. subsp. chacoense Hassl. var. genuinum Hassl. forma floribundum Hassl." Type. Paraguay/Argentina. [Presidente Hayes/Formosa]: "ad ripam fluminis, in regione cursus inferioris fluminis Pilcomayo [orillas de los ríos - ex protologue]", Jul 1906, T. Rojas 108d (lectotype, designated by Morton 1976, pg. 141 [as type]: G [G00306748, Morton neg. 8662]; isolectotype: G [G00306753]).

Solanum nigrum L. var. subhastatum Hassl., Trab. Mus. Farmacol. 21: 104. 1909, as " Solanum nigrum L. subsp. chacoense Hassl. var. subhastatum Hassl." Type. Paraguay/Argentina. [Presidente Hayes/Formosa]: "ad ripam fluminis, in regione cursus inferioris fluminis Pilcomayo [en los campos humedos - ex protologue]", May 1906, T. Rojas 108a (lectotype, designated by Morton 1976, pg. 141 [as holotype]: G [G00306747]).

Solanum nigrum L. forma longepedunculatum Hassl., Trab. Mus. Farmacol. 21: 105. 1909, as " Solanum nigrum L. subsp. chacoense Hassl. var. genuinum Hassl. forma longepedunculatum Hassl." Type. Paraguay/Argentina. [Presidente Hayes/Formosa]: "ad ripam fluminis, in regione cursus inferioris fluminis Pilcomayo [orillas del río - ex protologue]", May 1906, T. Rojas 108 (lectotype, designated by Morton 1976, pg. 141 [as holotype]: G [G00306746]).

Solanum nigrum L. forma longepetiolatum Hassl., Trab. Mus. Farmacol. 21: 105. 1909, as " langepetiolatum ", as " Solanum nigrum L. subsp. chacoense Hassl. var. genuinum Hassl. forma langepetiolatum Hassl." Type. Paraguay/Argentina. [Presidente Hayes/Formosa]: "ad ripam fluminis, in regione cursus inferioris fluminis Pilcomayo [arenales en las orillas del río - ex protologue]", May 1906, T. Rojas 108c (lectotype, designated Morton 1976, pg. 141 [as holotype]: G [G00306742, G00306743; two barcodes on same sheet]).

Solanum nigrum L. subforma sinuatodentatum Hassl., Trab. Mus. Farmacol. 21: 105. 1909, as " Solanum nigrum L. subsp. chacoense Hassl. var. subhastatum Hassl. forma langepetiolatum Hassl. subforma sinuatodentatum Hassl." Type. Paraguay/Argentina. [Presidente Hayes/Formosa]: "ad ripam fluminis, in regione cursus inferioris fluminis Pilcomayo [arenales en las orillas del río - ex protologue]", May 1906, T. Rojas 108b (lectotype, designated by Morton 1976, pg. 141 [as holotype], second step designated here: G [G00306745, G00306744; two barcodes on same sheet]; isolectotype: G [G00306740, G00306741, two barcodes on the same sheet]).

Solanum nigrum L. var. brevipetiolare (Chodat) Chodat & Hassl., Trab. Mus. Farmacol. 21: 105. 1909, as " Solanum nigrum L. subsp. chacoense Hassl. var. brevipetiolare Chodat & Hassl." Type. Based on Solanum pilcomayense Morong var. brevipetiolare Chodat.

Solanum nigrum L. forma pilcomayense (Morong) Hassl., Trab. Mus. Farmacol. 21: 105. 1909, as " Solanum nigrum L. subsp. chacoense Hassl. var. brevipetiolare Hassl. forma pilcomayense (Morong) Hassl." Type. Based on Solanum pilcomayense Morong.

Solanum nigrum L. forma brevipetiolare (Chodat) Hassl., Trab. Mus. Farmacol. 21: 105. 1909, as " Solanum nigrum L. subsp. chacoense Hassl. var. brevipetiolare Chodat & Hassl. forma brevipetiolare Hassl.", nom. illeg. superfl. non Solanum nigrum forma brevipetiolare (Chodat) Chodat (1903). Type. Based on Solanum pilcomayense Morong var. brevipetiolare Chodat.

Solanum pulchrilobum Bitter, Repert. Spec. Nov. Regni Veg. 11: 4. 1912. Type. Paraguay/Argentina. [Presidente Hayes/Formosa]: "ad ripam fluminis, in regione cursus inferioris fluminis Pilcomayo [arenales en las orillas del río - ex protologue]", May 1906, T. Rojas 108b (syntypes: B, destroyed [F neg. 2755]: lectotype, designated by Morton 1976, pg. 141, second step designated here: G [G00306745, G00306744; two barcodes on same sheet]; isolectotype:G [G00306740, G00306741, two barcodes on the same sheet]).

Solanum pulchrilobum Bitter var. paucilobum Bitter, Repert. Spec. Nov. Regni Veg. 11: 5. 1912. Type. Paraguay/Argentina. [Presidente Hayes/Formosa]: "ad ripam fluminis, in regione cursus inferioris fluminis Pilcomayo", May 1906, T. Rojas 108c (holotype: B, destroyed; lectotype, designated by Morton 1976, pg. 141 [as isotype]: G [G00306742, G00306743; two barcodes on same sheet]).

Solanum basilobum Bitter, Repert. Spec. Nov. Regni Veg. 11: 215. 1912. Type. Argentina. Chaco: Barranqueras, 27 Aug 1892, G. Niederlein 284 (holotype: B, destroyed [F neg. 2864]; lectotype, designated by Barboza et al. 2103, pg. 253: PH [00030388]).

Solanum syringoideum Bitter, Repert. Spec. Nov. Regni Veg. 11: 225. 1912. Type. Paraguay. "Gran Chaco, ad ripam occidentalem flum.", T. Rojas in É. Hassler 2324 (holotype: B, destroyed [F neg. 2758]; lectotype, designated here: BM [BM000087562]; isolectotypes: G [G00306749, G00306750, G00306751, G00306753, G00306755], GH [00105872], K [K000585693], W [acc. # 1906-0001034]).

Solanum syringoideum Bitter var. pycnostichanthum Bitter, Repert. Spec. Nov. Regni Veg. 11: 225. 1912. Type. Paraguay. "Gran Chaco, ad ripam occidentalem flum." 1903, T. Rojas in É. Hassler 2393 (holotype: B, destroyed [F neg. 2758]; lectotype, designated by Morton 1976, pg. 141: G [G00306737]; isolectotypes: BM [BM000087587], K [K000585694]).

Solanum pulchrilobum Bitter var. longepetiolatum (Hassl.) Parodi, Tomo Conmem. 25 Aniv. Fund. Fac. Agron. Vet. Buenos Aires 85. 1929. Type. Based on Solanum nigrum L. var. longepetiolatum Hassl.

Solanum deltaicum Cabrera, Fl. Prov. Buenos Aires 5a: 215. 1965. Type. Argentina. Buenos Aires: Delta, Paraná Miní, 18 May 1950, A.L. Cabrera 10626 (holotype: LP [LP005356]).

Solanum pilcomayense Morong var. vicinum C.V.Morton, Revis. Argentine Sp. Solanum 143. 1976. Type. Argentina. Tucumán: Dpto. Leales: Chañar Pozo, 5 Nov 1919, S. Venturi 624 (holotype: US [00027744, acc. # 1548361]; isotypes: A [00077736], SI [075135, acc. # 167305, 137336, acc. # 167305b]).

Type.

Paraguay. Pilcomayo River , 1888-1890, T. Morong 898 (lectotype, designated here: NY [00172130]; isotypes: BM [BM000087584], E [E00106293], GH [00077735], MICH [1109928], MO [MO-503704, acc. # 3575651], PH [00030470], US [00027743, acc. # 48030; 00650476, acc. # 1324704], WIS [v0256204WIS]).

Description.

Perennial herbs or subshrubs to 1.5 m, woody at the base, the branches sprawling on other vegetation. Stems terete, distally thin and sprawling, minutely puberulent with eglandular, translucent simple uniseriate 2-5-celled trichomes 0.5-1 mm long, these usually antrorse; new growth densely to moderately pubescent with translucent simple uniseriate 2-5-celled trichomes 0.5-1 mm long; bark of older stems pale yellowish tan. Sympodial units difoliate, the leaves usually not, but occasionally, geminate. Leaves simple, entire or shallowly toothed, the blades 2-8(11) cm long, 1.5-5(7) cm wide, obovoid to oblanceolate, distinctly triangular in outline, widest in the lower quarter, membranous, concolorous; adaxial and abaxial surfaces sparsely and evenly pubescent with translucent simple uniseriate trichomes 0.5-1 mm long, these denser along the veins; principal veins 5-6 pairs, drying paler than the lamina; apex acute to acuminate; margins entire or shallowly toothed in the lower third, if present the sinuses ca. 1/4 of the way to the midrib (e.g., Rojas 108b, F neg. 2755, type of S. pulchrilobum ), the teeth with acute to slightly rounded tips; base abruptly truncate; petiole 1-3(-4) cm long, sparsely pubescent like the stems. Inflorescences internodal or occasionally opposite the leaves, usually unbranched but occasionally forked (e.g., Schinini et al. 10021), 1.5-4 cm long, with 5-10(15) flowers, sparsely and evenly pubescent with simple uniseriate mostly antrorse trichomes ca. 0.5 mm long like the stems; peduncle 1.4-2.5(3) cm long; pedicels 0.8-1.3 cm long, ca. 0.5 mm in diameter at the base, ca. 1 mm in diameter at the apex, spreading at anthesis, articulated at the base with a somewhat swollen insertion point; pedicel scars closely spaced ca. 0.5 mm apart, mostly clustered at the tips of the inflorescence. Buds ellipsoid, the corolla strongly exserted from the calyx tube before anthesis. Flowers 5-merous, cosexual (hermaphroditic). Calyx tube ca. 1.5 mm long, conical, the lobes 1-2.5 mm long, long-triangular, often unequal in size, the sinuses rounded, the tips blunt, sparsely pubescent with simple uniseriate trichomes like the rest of the inflorescence. Corolla 1.2-1.8 cm in diameter, white with a green central eye, deeply stellate, lobed 3/4 of the way to the base, the lobes 4-5.5 mm long, 2-2.5 mm wide, reflexed then spreading at anthesis, adaxially glabrous, abaxially minutely puberulent with unicellular papillae, these denser on the tips and margins. Stamens equal; filament tube minute; free portion of the filaments ca. 0.5 mm long, densely pubescent adaxially with tangled, translucent simple uniseriate trichomes; anthers 3-4 mm long, 0.75-1.1 mm wide, ellipsoid, yellow, the abaxial surfaces sometimes somewhat papillate, poricidal at the tips, the pores lengthening to slits with age. Ovary conical, glabrous; style 5-6 mm long, straight, exserted beyond the anther cone, densely pubescent in the lower third inside the anther cone; stigma minutely capitate, the surface minutely papillose. Fruit a globose berry, 0.5-0.7 cm in diameter, green becoming black or dark purple when ripe (some collections from Paraguay mention “red” berries, e.g., Zardini &Tilleria 35278), the pericarp thin, matte to somewhat shiny, opaque, glabrous; fruiting pedicels 1.9-2.5 cm long, ca. 0.5 mm in diameter at the base, ca. 1.5 mm in diameter at the apex, spreading, somewhat woody, not persistent; fruiting calyx not accrescent, the lobes not enlarged. Seeds 40-60 per berry, ca. 1.5 mm long, ca. 1 mm wide, flattened and teardrop shaped, pale tan, the surfaces minutely pitted, the testal cells pentagonal to somewhat sinuate in outline. Stone cells 2-4 per berry, ca. 0.5 mm in diameter, usually found close together in the berry, cream-coloured. Chromosome number: n = 12 ( Moscone 1992, voucher Di Fulvio 806; Moyetta et al. 2013, vouchers Barboza et al. 2279, 2287).

Distribution

(Fig. 127 ). Solanum pilcomayense occurs primarily in the Paraná River Basin, in Brazil (States of Mato Grosso, Mato Grosso do Sul, Pará, Paraná, Rio Grande do Sul), Bolivia (Depts. Bení, Santa Cruz), Paraguay (Depts. Alto Paraguay, Boquerón, Central, Concepción, Cordillera, Misiones, Presidente Hayes) and Argentina (Provs. Buenos Aires, Chaco, Corrientes, Entre Ríos, Formosa, Santa Fé, Santiago del Estero, Tucumán). It has been found sporadically outside of this native range in Europe (see Särkinen et al. 2018) and the United States of America (see Knapp et al. 2019), mostly associated with wool waste and sheep-related imports.

Ecology and habitat.

Solanum pilcomayense is a plant of wet areas in dry forests (Chaco and Chiquitano woodlands) and swampy areas along streams and rivers, from near sea level to 1,000 m elevation.

Common names and uses.

No common names recorded on specimens seen. Solanum pilcomayense is used to treat “cadillo” (corns and calluses) in folk medicine (Argentina, Corrientes; Martínez Crovetto 1981).

Preliminary conservation status

( IUCN 2022). Least Concern [LC]. EOO = 15,437,317 km2 [LC]; AOO = 768 km2 [EN]. Solanum pilcomayense is widely distributed along rivers in the Paraná Basin; it has been collected in protected areas in Argentina (e.g., Parque Nacional Iberá, Parque Nacional Río Pilcomayo) and Paraguay (e.g, Parque Nacional Ypoá).

Discussion.

Solanum pilcomayense is a distinctive species of the Paraná River Basin with broadly triangular leaves widest in the lower quarter with truncate to somewhat hastate bases, large corollas and dark purple berries with two apical stone cells. It often grows in flooded areas along rivers and streams and stems can be very long and sprawling over other vegetation. The calyx lobes are distinctly spathulate, in contrast to the sympatric S. americanum with deltate calyx lobes and much smaller (1-1.5 mm versus 3-4 mm long) anthers. Solanum pilcomayense also differs from S. americanum in its deciduous (versus persistent) fruiting pedicels. Two very old collections of S. pilcomayense have been seen in the United States of America, in coastal Texas and New Jersey, probably from 19th century ship’s ballast, but the species has not persisted outside of its native range (see Knapp et al. 2019).

Barboza et al. (2013) cited the sheet of Morong 898 in NY (barcode 00172130) as the holotype of S. pilcomayense in error, no herbaria were cited in the protologue. We here select this sheet explicitly as the lectotype for the name.

Bitter (1912b) cited specimens at B collected by Hassler and Rojas to coin names we here recognise as synonyms of S. pilcomayense , these specimens were exactly the same collections Hassler (1909) had previously used to coin his names (mostly at the infraspecific level). Most of these were inadvertently effectively lectotypified by Morton (1976) by citing “holotype” or" isotype" (see above). The only name he did not effectively lectotypify was S. syringoideum Bitter which we here lectotypify with the duplicate of Rojas in Hassler 2324 in BM (BM000087562) so as not make it homotypic with S. nigrum var. chacoense that Morton (1976) inadvertently lectotypified with the sheet of this number in Geneva.

The various collections of Teodoro Rojas used by Hassler (1909) to describe infraspecific taxa of S. nigrum treated here as synonyms of S. pilcomayense were also used by Bitter (1912b) to describe S. pulchrilobum . In the herbarium at G they are labelled in such a way that a single sheet has on it two barcodes, one for each name. We have lectotypified these names with the same set of specimens and have cited both barcodes that are on individual sheets (e.g. Rojas 108b - https://www.ville-ge.ch/musinfo/bd/cjb/chg/adetail.php?id=314895&base=img&lang=en). The way in which specimens are kept at G (see Turland et al. 2018: Art. 8.3, Ex. 9) means that despite the barcoding, these “duplicates” of Rojas 108b are all considered the same specimen, thus rendering S. nigrum subforma sinuatodentatum and S. pulchrilobum homotypic.

Hassler (1918) treated S. pilcomayense in Paraguay as a complex series of names at nested ranks of subspecies, variety and forma. He recognised S. syringoideum at the specific level, but in a very confusing paragraph listed all his own ( Hassler 1909) and Bitter’s (1912b) previous infraspecific taxa under his S. nigrum var. chacoense , apparently creating new names, but really only listing them in synonymy and equating taxon concepts.

Figures

Figure 125. Solanum pilcomayense A flowering and fruiting habit B eglandular leaf trichome C calyx D glandular trichome of the calyx E flower F dissected flower G eglandular trichome of the corolla H stamen, dorsal view I stamen, ventral view J gynoeciu K frui L fruit, longitudinal section M seed N seed, longitudinal section (A-N Barboza et al. 2287). Illustration by P. Peralta. Previously published in Barboza et al. (2013: 254).

Figure 126. Solanum pilcomayense A habit (live plant) B habit (herbarium sheet) C inflorescences with buds D flowers at full anthesis E fruiting branch with maturing fruits (A Pena-Chocarro et al. 1496 B-D Rojas 108 [G 00306746] E Morong 898 [PH 00030470]). Reproduced with permission of the Conservatoire et Jardins Botaniques de la Ville de Geneve and the Philadelphia Academy of Sciences (Drexel University).

Figure 127. Distribution map of Solanum pilcomayense.