Solanum nigrescens M.Martens & Galeotti, Bull. Acad. Roy. Sci. Bruxelles 12(1): 140. 1845

Knapp, Sandra, Barboza, Gloria E., Bohs, Lynn & Saerkinen, Tiina, 2019, A revision of the Morelloid Clade of Solanum L. (Solanaceae) in North and Central America and the Caribbean, PhytoKeys 123, pp. 1-144 : 65-71

9. Solanum nigrescens M.Martens & Galeotti, Bull. Acad. Roy. Sci. Bruxelles 12(1): 140. 1845 Figures 27 , 28

Solanum nodiflorum Jacq. var. puberulum Dunal, Prodr. [A. P. de Candolle] 13(1): 46. 1852. Type. United States of America. Texas: [Bexar County] "Mexico, Bejar", Oct 1828, J.L. Berlandier 1904 (lectotype, designated by Edmonds 1972, pg. 103 [as holotype]: G-DC [G00144231]; isotypes: MO [acc. # 5481286], NY [NY00743232], P [P00319514], W [acc. # 0022313]).

Solanum caribaeum Dunal, Prodr. [A. P. de Candolle] 13(1): 48. 1852. Type. Jamaica. Sin.loc., [protologue - "In insulis Caribaeis, Jamaica, Guadalupâ”], no date, Anon. s.n. (lectotype, designated by D’Arcy 1974a, pg. 735: G-DC [G0000144199]).

Solanum crenatodentatum Dunal var. ramosissimum Dunal, Prodr. [A. P. de Candolle] 13(1): 54. 1852. Type. United States of America. Louisiana: "Basse Louisiane", 1839, G.D. Barbe 82 (holotype: P [P00362535]).

Solanum nigrum L. var. nigrescens (M.Martens & Galeotti) Kuntze, Revis. Gen. Pl. 2: 455. 1891. Type. Based on Solanum nigrescens M.Martens & Galeotti

Solanum nigrum L. var. amethystinum Kuntze, Revis. Gen. Pl. 2: 455. 1891. Type. Costa Rica. San José /Cartago: “Irazu”, 24 Jun 1874, O.E. Kuntze s.n. (neotype, designated here: NY [NY00688134]).

Solanum prionopterum Bitter, Repert. Spec. Nov. Regni Veg. 11: 5. 1912. Type. Venezuela. Distrito Federal: "Caracas, in arena ad rivulum in valle loci dicti Valle", 25 Mar 1854, J. Gollmer s.n. (holotype: B, destroyed [F neg. 2699], possibly the same original material as the type of S. gollmeri ; no duplicates found).

Solanum gollmeri Bitter, Repert. Spec. Nov. Regni Veg. 11: 202. 1912. Type. Cultivated in Berlin ("horto bot. Berol.") from seeds sent from Caracas, Venezuela by J. Gollmer, 1859, Without collector s.n. (holotype: B, destroyed [F neg. 2689]; lectotype, designated here: F [V0361922F, acc. # 621268], mounted on sheet with F neg. 2689).

Solanum pruinosum Dunal var. phyllolophum Bitter, Repert. Spec. Nov. Regni Veg. 12: 77. 1913. Type. Cultivated in Europe, seeds from Mexico from David Fairchild as USDA-32065 [protologue "sub. no. 32065, Mexico, S. nigrum "] (no specimens cited, probably described from living plants; original material at B?).

Solanum subelineatum Bitter, Repert. Spec. Nov. Regni Veg. 12: 79. 1913. Type. Cultivated at Bremen from seeds from Mexico sent by U. S. Dept. Agriculture, Bureau of Plant Industry, no. 32067 (original material in Bremen?, destroyed; possibly described from living material).

Solanum oligospermum Bitter, Repert. Spec. Nov. Regni Veg. 12: 80. 1913. Type. Mexico. Oaxaca: Sierra de San Felipe, 7500 ft., Oct 1894, C.G. Pringle 4948 (lectotype, designated by Edmonds 1972, pg. 108 [as holotype]: Z [Z000033841]; isolectotypes: BM [BM001017184], BR [BR0000005537983], E [E00570141], GOET [GOET003559], HBG [HBG511469], KFTA [KFTA0000498], NDG [NDG45082], NY [NY00139012], PH [PH00030459], S [acc. # S-G5704], US [US00027711, acc. # 251984; US01014256, acc. # 1418095], W [acc. # 1895-0004424]).

Solanum durangoense Bitter, Repert. Spec. Nov. Regni Veg. 12: 82. 1913. Type. Mexico. Durango: "prope urbem Durango", Apr 1896, E. Palmer 101 (holotype: B, destroyed; lectotype, designated by D’Arcy 1974a, pg. 738: US [US00027556, acc. # 304231]; isolectotypes: BM [BM001034665], F [V0073093F, acc. # 51213, F. neg. 052464], K [K000063870], MO [MO-568723, acc. # 1718478], NY [NY00138982]).

Solanum purpuratum Bitter, Repert. Spec. Nov. Regni Veg. 13: 85. 1913. Type. Bahamas. Andros Island: Coppice, near Fresh Creek, Northern Section, 28-13 Jan 1910, J.K. Small & J.J. Carter 8805 (holotype: P [P00369223]; isotypes: F [acc. # 283797], K [K001161011], NY [NY00111385], US [US00027765, acc. # 758168]).

Solanum approximatum Bitter, Repert. Spec. Nov. Regni Veg. 13: 86. 1913. Type. Jamaica. Saint Andrew: Hardwar Gap, 4000 ft., 17 Jun 1903, G.E. Nichols 89 (holotype: B, destroyed; lectotype, designated here: NY [NY00111374]; isolectotypes: F [F0073167F, acc. # 147000], GH [GH00077545], MO [MO-503650, acc. # 1815480], US [US00027456, acc. # 429037], YU [YU065289]).

Solanum amethystinum (Kuntze) Heiser, Ceiba 4: 296. 1955. Type. Based on Solanum nigrum L. var. amethystinum Kuntze

Solanum costaricense Heiser, Ceiba 4: 297. 1955. Type. Costa Rica. Heredia: La Paz, by waterfall, on road to Vara Blanca, about 29 mi. from Heredia, 1400 m, 13 Sep 1953, C.B. Heiser 3536 (holotype [two sheet holotype]: IND [IND1000067, acc. # 95105; IND1000068, acc. # 95106]; isotypes: CORD [CORD00004189], US [cited in protologue, n.v.]).

Type.

Mexico. Oaxaca: “Cordillera” ["aux bords des ruiseaux de la cordillera de Yavezia"], Nov-Apr 1848, H. Galeotti 1238 (lectotype, designated by D’Arcy 1974a, pg. 737: P [P00337261]; isolectotypes: BR [BR000000825045, BR0000008250483], W [acc. # 0022312, acc. # 1889-0291397]).

Description.

Perennial herbs to 3 m tall, sometimes epiphytic. Stems terete or more usually angled to ridged, green or sometimes tinged purplish green, usually lax and somewhat scrambling, glabrescent to sparsely pubescent with antrorse simple eglandular uniseriate trichomes to 1 mm long, these white when dry and usually somewhat curved, occasionally on older stems the trichome bases enlarged and forming spinescent processes; new growth more densely pubescent. Sympodial units difoliate, geminate or not, the leaves if paired of similar size and shape. Leaves simple, (1.5)4-10.5(15) cm long, (0.5)2-5(7.5) cm wide, elliptic to elliptic ovate, membranous; surfaces sparsely to moderately pubescent with simple eglandular uniseriate trichomes to 1 mm long, these denser on the veins and abaxially; principal veins 5-6 pairs; base abruptly attenuate, usually decurrent on the petiole; margins entire to sinuate or dentate, the teeth irregular and unevenly spaced, often larger in the basal half of the lamina; apex acute or occasionally acuminate; petiole 0.5-2 cm long, sparsely pubescent like the stems and leaves. Inflorescence 1-3.5 cm long, lateral and internodal, unbranched to occasionally forked, with (2)5-10 flowers clustered at the tip (sub-umbelliform) or spaced along the rhachis (depending on inflorescence age), sparsely pubescent with antrorse simple eglandular trichomes like the stems; rhachis 0.3-1 cm long; peduncle 1-2.5 cm long, slender, spreading; pedicels 0.4-0.7 cm long, slender and threadlike, spreading at anthesis, ca. 1 mm in diameter at the base, ca. 0.5 mm in diameter at the apex, sparsely pubescent like the inflorescence axis. Buds ellipsoid with blunt tips, the corolla strongly exserted from the calyx tube long before anthesis. Flowers 5-merous, all perfect. Calyx tube 1-1.2 mm, conical, the lobes 0.5-0.8(1) mm long, 0.5-1 mm wide, broadly deltate to deltate, the apices acute or occasionally somewhat rounded. Corolla 8-10 mm in diameter, white or less often pale purple, with a green or yellow-green (very occasionally dark purple) central portion near the base of the lobes, stellate, lobed ca. 3/4 of the way to the base, the lobes 3-4 mm long, 1.5-2 mm wide, narrowly triangular, reflexed or spread ing, densely papillate abaxially, the papillae ca. 0.1 mm long, denser at the tips and margins. Stamens equal; filament tube minute; free portion of the filaments 0.5-2 mm long, densely pubescent adaxially with tangled simple trichomes; anthers 2-2.8(3) mm long, 1-1.1 mm wide, yellow, ellipsoid or narrowly ellipsoid, sagittate at the base, poricidal at the tips, the pores lengthening to slits with age. Ovary globose, glabrous; style 3.5-5 mm long, usually somewhat curved, often exserted from the bud before anthesis, densely pubescent in the basal 2/3 (the portion inside the anther cone), exserted from the anther cone; stigma minutely capitate, the surface papillose. Fruit a globose berry, 6-8 mm in diameter, dull green to purplish black at maturity, opaque, the pericarp thin and usually matte but sometimes slightly shiny; fruiting pedicels 10-12 mm long, ca. 0.5 mm in diameter at the base, ca. 1 mm in diameter at the apex, not markedly woody, spreading, dropping with mature fruits or occasionally remaining on the inflorescence rhachis; fruiting calyx not accrescent, tube ca. 1 mm long, the lobes 0.5-1.1 mm long, spreading and appressed to the berry, very occasionally somewhat reflexed. Seeds (5)10-50 per berry, 1.2-1.5 mm long, 1-1.1 mm wide, tear-drop shaped, pale brown to yellow, the surfaces minutely pitted, the testal cells square or pentagonal in shape, becoming elongate and rectangular near the subapical hilum. Stone cells 4-13, mostly commonly 5 or 6, rather large ca. 0.5 mm in diameter. Chromosome number: 2n =2 × =24 ( Heiser 1955 as S. costaricense ; Heiser et al. 1965 as S. amethystinum ).

Distribution.

(Figure 29 ) Solanum nigrescens is a widespread species ranging from the southeastern United States of America through Central America, northern South America, and the Caribbean; in the southeastern United States of America it is found along the Gulf Coast and slightly inland but does not extend to the Great Plains.

Ecology.

Solanum nigrescens is most commonly collected from open areas in cloud forests, deciduous forests and pine forests between sea level and 3,000 m elevation in the region, but most common at lower elevations (ca. 1500 m) in Central America.

Common names.

United States of America. Divine nightshade ( NatureServe 2017, although the record of this species from Hawaii is certainly in error). Mexico and Central America. Hierba (yerba) mora (many sources). Mexico [Campeche] Chilillo (Chan 6138), [Chiapas] Cha’uku (Lacandon, Lévy & Durán 253), Ch’il wamal (Tzeltal, López Pérez 332), Moen (moem, mu’em) (Tzeltal, Isidro V. 764, Mendez Ton 4546, 6419, Reyes-García et al. 7431, Shilom Ton 7625), Moral wama (Tzeltal, Gómez López 309), Mu Itaj (Tzotzil, Pérez Gómez 159), Tukumal ejal (Tzotzil, Pérez Gómez 76), [Durango] Capulín ( González 1410), [Guerrero] Yao narambo (Wagenbreth 120), yuwa tii (Avila 52), [Hidalgo] Tomaquilit (Villa 48), [ Michoacán] Hierba de golpe (Hinton 5709), [Oaxaca] Bishate (bishte, bisnate) (Elorsa C. 27, 4724), Bzat (Zapotec, Hunn OAX-838), Mahuán (Chinantec, Martínez Calderón 778), Pchfuzch-yaas (Zapotec, Hunn OAX-1056), Pipitzco (Macias Acevedo 13), Quizh-jpchuux-las (Zapotec, Hunn 1849), Tomatal montes (Zarate Marcos 546), Tonchichi (Camacho 20), [Puebla] Barbechos ( Solís M. 4904), Quelite de jitomate ( Jiménez Chimil JDA-30419), Teconchichi (Tlapa & Ubierna 162, 232), Tomalkilit (Nahuat, Ledesma et al. JDA-20153), [Sonora] Chichiquelite (Felger et al. 1361), Mamya (Yaqui, Felger et al. 1361), Mombia (mambia) (Mayo, Van Devender et al. 93-1012), [ Yucatán] Berenjena xiu ( Enríquez 315), Chilillo ( Góngora 137), Ik koox ( Ucán Ek 4360), [Veracruz] Mustulúk (Totonaco, Cortés 156), Tomatito de sabana (Murrieta 56). Guatemala. Ix ch’yauk’ (Mopan Maya, Ventur 27), Macuy ( Ramírez & García 397). Panama. Kabur gi (Kuna Yala, de Nevers et al. 7484).

Uses.

Leaves widely used a potherb ( “quelite”) in Mexico and Central America.

Preliminary conservation status ( IUCN 2017).

Least Concern (LC). Solanum nigrescens is widespread and weedy in the southern United States, throughout Mexico and Central America and in the Caribbean; it also occurs in northern South America. It has been registered as a noxious weed of agriculture in Louisiana ( Orgeron et al. 2018). For EOO see Table 6 .

Discussion.

Solanum nigrescens is one of the commonest and most widely distributed of all morelloid species in Central America of America and the Caribbean. It is very variable morphologically, perhaps due to its wide ecological tolerance and occurrence in many different habitats. It is sympatric or occurs parapatrically with S. americanum , S. douglasii (in Mexico), S. interius and S. pseudogracile . It may hybridize with S. americanum in the southeastern United States (see discussion under S. americanum ). Distinguishing features of each of those taxa can be found in the discussions of those species. Solanum nigrescens is a perennial and has been reported to be epiphytic ( D’Arcy 1974a, b). Where it and S. americanum occur in sympatry, the matte berries with appressed to spreading calyx lobes of S. nigrescens are distinct from the shiny berries with strongly reflexed tiny calyx lobes of S. americanum ; anther length also differs (0.7-1.5 mm in S. americanum versus 2-2.8(3) mm in S. nigrescens ). In central Mexico, were S. nigrescens and S. douglasii co-occur, anther length (3-4 mm in S. douglasii versus 1.8-2.5 mm in S. nigrescens ) is a good distinguishing feature; in fruit, these two taxa can be almost impossible to tell apart. Nee (1993) considered S. nigrescens to occupy wetter forest types than does S. douglasii but did not have not enough material from Veracruz to make the distinction. We find that the two species occur in very similar habitats, but that S. nigrescens is a more Caribbean species on the eastern side of the Sierra Madre and around the Gulf of Mexico, while S. douglasii occurs along the Pacific coast and into central Mexico, but also does occur in the Chihuahuan Desert biome. Specimens from Quintana Roo identified as S. nigrum in Sousa and Cabrera (1983) are S. nigrescens (Cabrera 875, 1151). Like most of these morelloid species, it is very weedy and occupies a wide range of disturbed and undisturbed habitats.

In the southeastern United States (e.g., Texas) the distributions of S. nigrescens and S. interius are very close if not interdigitating. Solanum nigrescens can be distinguished from S. interius in its smaller seeds, more numerous stone cells in the berry and usually acute calyx lobe apices. The unusual pedicel articulation of the basal flower (in the lower third of the pedicel) in the inflorescences of S. interius has not been seen in S. nigrescens . Solanum nigrescens also appears to occur in more mesic and coastal habitats than S. interius , which is a species of the Great Plains.

Material identified as S. americanum by Manoko et al. (2007) represents specimens of S. nigrescens (see Särkinen et al. 2018: 61).

Bitter (1914) reported large numbers of stone cells in the berries of many of the names we consider synonyms of S. nigrescens . In general, S. nigrescens has more stone cells in its berries than does the similar S. douglasii , but these can be difficult to see as some of them are very tiny.

Dunal (1852) cited several specimens in describing S. nodiflorum var. puberulum , all from the Candolle herbarium at G: "Carolina meridionali, Fraser ", "Florida, Mich.f. ", "Mexico circa Bejar, Berlandier 1904 " and "China, Staunton ". Of these, the Fraser collection is a mixed collection composed of two tiny fragments of S. nigrescens (G00144217) and one larger fragment of Capsicum annuum L. (G00144268), mounted on the same sheet is a tiny fragment of S. americanum attributed to Michaux filius (G00144264), and the Staunton sheet (G00144265) is of a plant of S. americanum . Edmonds inadvertently (see Prado et al. 2015) selected as the lectotype for this name the sheet of Berlandier 1904 held in G-DC (G00144231) by citing it as “holotype”; this is fortunate because it is unambiguous, was cited by Dunal (1852), and has duplicated in several other herbaria. When Berlandier was collecting, southern Texas was part of Mexico, and Bejar was the name for what today is San Antonio, the capital of Bexar County.

D’Arcy (1974a) lectotypified Solanum caribaeum citing a specimen from Jamaica in "G-DC ex Kew". In the protologue of S. caribaeum Dunal (1852) cited "In insulis Caribaeis, Jamaica, Guadalupâ (ex h. DC)" suggesting that more than one specimen was consulted. In G-DC there is a single specimen with the label "S. caribearum Nob. 1835" (G00144199) that is the only element of unambiguous material we have seen, and we designate this sheet in a second stage lectotypification. It is clear that more than this single sheet was used in the preparing the description, G00144199 has only fruits and the description has details of both flowers and fruits.

Kuntze (1891) equated his S. nigrum var. amethystinum with " S. nigrum subsp. genuinum Sendtn." a name not validly published (see Särkinen et al. 2018) and distinguished it by its violet flowers. He did not explicitly cite specimens but did cite the locality "Costa Rica. Irazu". We have selected the specimen in Kuntze’s herbarium held at NY (NY00688134) as the neotype for this name.

Both S. prionopterum ( Bitter 1912a) and S. gollmeri ( Bitter 1912b) were described from material collected by J. Gollmer around Caracas, in two separate publications. It is likely that the seed collection grown in Berlin in 1859 that was used to describe S. gollmeri was derived from the same material collected in 1854 in Venezuela. The holotypes in B for both these names were destroyed; the photograph of the holotype of S. gollmeri (F neg. 2689) has a tiny leaf fragment attached, but no such material is associated with the photograph taken of the holotype of S. prionopterum (F neg. 2699). We designate this fragment (F-621268) as the lectotype of S. gollmeri ; it is not, however, original material for S. prionopterum , and we hope a duplicate of the Gollmer collection from 1854 used to describe S. prionopterum will eventually be found.

Bitter (1913) described S. pruinosum var. phyllolophum from living material originally sent by David Fairchild of the USDA as No. 32065; he cited no specimens. In the Germplasm Resources Information Network of the USDA ( USDA 2017) the germplasm accession PI-32065 is recorded as " S. nigrum " collected by C.A. Purpus in Puebla, Mexico. Fairchild (1912) recorded the exact locality as "Esperanza, Puebla, 2,700 m [9,850 feet]". We have not yet seen a collection made by Carl Purpus with this exact information, hence do not designate a neotype until we have searched more exhaustively for a collection with the correct locality. It may be Purpus only collected seeds, and not herbarium specimens.

Bitter (1913) described S. subelineatum from living material original sent from the USDA as No. 32067 grown in the Bremen botanical garden; he cited no specimens. In the Germplasm Resources Information Network of the USDA ( USDA 2017) the germplasm accession PI-32067 is recorded as " S. nigrum " collected by C.A. Purpus in San Luis Potosí, Mexico. Fairchild (1913) recorded the exact locality as "Rascon, San Luis Potosí, 400 to 500 m [1,300 to 1,650 feet]". As with S. pruinosum var. phyllolophum we refrain from lectotypifying this anticipating encountering a duplicate.

In describing S. oligospermum Bitter (1913) cited two specimens of Pringle 4948 at "herb. Haussknecht.!, Turic.!" (today JE and Z). Edmonds (1972) inadvertently lectotypified this name with the Z sheet by stating "(Z holotype!)" (see Prado et al. 2015). We here specify the individual sheet (Z000033841) in that herbarium that is the lectotype. There are many well-preserved duplicates of this collection (see synonymy), all with flowers and fruit.

Solanum approximatum , S. durangoense , and S. purpuratum were described ( Bitter 1913) from B sheets that are now destroyed. We have selected lectotypes for these names from the large number of extant duplicates, using the best-preserved sheets with both flowers and fruits (if possible).

Many specimens of S. nigrescens from Venezuela in US were annotated as " S. jahnii Bitter" by C.V. Morton, a designation not validly published (nomen nudum) based on Jahn 588. That collection corresponds to S. interandinum Bitter, a taxon not known from Central America or Mexico.

Heiser (1955) cited only IND as the type in the protologue of S. costaricense , two sheets in IND are labelled “Type”. The sheets are clearly labelled as "sheet 1" and "sheet 2" and we interpret them as a two-sheet holotype (see Turland et al. 2018, Art. 8, Ex. 7). IND-1000068 is the better material, with flowers and complete vegetative material.

Specimens examined.

See Suppl. materials 1 and 3.

Figures

Figure 27. Solanum nigrescens M. Martens & Galeotti. A New shoot B flower C inflorescence with mature fruit (A-C Ventura A. 672). Drawing by L. Ribulgo.

Figure 28. Solanum nigrescens M. Martens & Galeotti. A Leaves B flowering branch C inflorescence with flowers at full anthesis D developing fruits (A-D Amith F 0055). Photos by M. Gorostiza Salazar.

Figure 29. Distribution of Solanum nigrescens M. Martens & Galeotti (points in northern South America included to show continuous distribution).