Solanum palitans C.V.Morton, Revis. Argentine Sp. Solanum 92. 1976

Saerkinen, Tiina, Poczai, Peter, Barboza, Gloria E., Weerden, Gerard M. van der, Baden, Maria & Knapp, Sandra, 2018, A revision of the Old World Black Nightshades (Morelloid clade of Solanum L., Solanaceae), PhytoKeys 106, pp. 1-223 : 1

10. Solanum palitans C.V.Morton, Revis. Argentine Sp. Solanum 92. 1976 Figures 31 , 32

Type.

Argentina. Tucumán: Dept. Tafí del Valle, Yerba Buena , 19 Jan 1919, S. Venturi 159 (holotype: US [00027724, acc. # 1548805]; isotypes: BA [BA2463], LIL [LIL001454], LP [ LP010926 ], MA, SI [ SI003329 ]) .

Description.

Annual, decumbent or prostrate herbs, the young plants sometimes erect, up to 15 cm tall often rooting at the lower nodes, forming dense patches, the branches to ca. 1 m long. Stems decumbent or ascending, terete or somewhat angled with ridges, green, older stems yellowish-brown, not markedly hollow; new growth pubescent with simple, spreading, uniseriate, translucent, eglandular trichomes, these 0.5-1 mm long, to or nearly glabrous; older stems glabrous. Sympodial units difoliate, the leaves not geminate. Leaves simple, 2.5-9 cm long, 2.5-7.5 cm wide, broadly ovate, thinly membranous, green, concolorous, without smell; adaxial surfaces glabrous to sparsely pubescent with simple hairs to 0.5 mm on the major veins; abaxial surfaces glabrous; major veins 3-4 pairs; base long attenuate, decurrent on the petiole; margins 3-lobed nearly to the midrib, rarely the lateral lobes themselves lobed, the terminal lobe ovate, the lateral lobes asymmetrically ovate or lanceolate-ovate, acute at the tips, the sinuses sometimes sparsely ciliate; apex acute; petioles 0.5-2 cm, winged to the base, glabrous or sometimes sparsely ciliate near the base. Inflorescences 1.2-2.5 cm, internodal or often just below a node, unbranched or rarely with a few branches, the flowers spaced along the rhachis, with 4-9 flowers, glabrous to sparsely pubescent; peduncle 0.7-1.4 cm long, delicate; pedicels 3-5 mm long, 0.2-0.3 mm in diameter at the base and at the apex, filiform, spreading, articulated at the base; pedicel scars spaced 1-5 mm apart. Buds ellipsoid, the corolla completely covered by the calyx tube before anthesis. Flowers 5-merous, all perfect. Calyx tube 1.5-2 mm long, cup-shaped, the lobes ca. 0.75-1.5 mm long, less than 1 mm wide, lanceolate-oblong, the tips acute, glabrous. Corolla ca. 7 mm in diameter, white or rarely light violet, rotate-stellate, lobed ca. 1/2 way to the base, the lobes 1.5-2.5 mm long, 1-2 mm wide at the base, reflexed or spreading at anthesis, abaxially minutely white-puberulent on the tips of the lobes, glabrous adaxially. Stamens equal; filament tube minute; free portion of the filaments 0.5-1 mm long, adaxially pubescent with tangled uniseriate trichomes; anthers 1.6-2 mm long, 0.7-0.8 mm wide, oblong or ellipsoid, yellow, poricidal at the tips, the pores lengthening to slits with age and drying. Ovary glabrous; style 2.3-3.3 mm long, glabrous or sparsely pubescent in the lower part where included in the anther cone, exserted 0.5-0.8 mm beyond anthers; stigma capitate, the surface minutely papillate, green in live plants. Fruit a depressed-globose and bilobed (especially when young) berry, 6-8 mm in diameter, pale yellow, the pericarp thin and somewhat shiny; fruiting pedicels 4-7 mm long, 0.5-0.7 mm in diameter at the base and at the apex, spreading, recurved at the base to hold the fruit downwards, nearly in contact with the soil, dropping with the mature fruit, not persistent; fruiting calyx not markedly accrescent but the lobes somewhat elongating in fruit, the tube 2-3 mm long, the lobes 2-3(-4) mm long, covering the basal 1/3 of the berry, the tips somewhat recurved. Seeds 20???30 per berry, 1.5-1.6 mm long, 1.2-1.6 mm wide, flattened reniform, light yellow, the surfaces pitted, the testal cells sinuate in outline. Stone cells 2(4) per berry, 2 larger and apical (1-1.5 mm in diameter), the other 2 equatorial, smaller, 0.5-0.6 mm in diameter. Chromosome number: 2n =2x=24 ( Moscone 1992; Moyetta et al. 2013).

Distribution

(Figure 33 ). Native to north-western and central Argentina, northern Chile and Bolivia and apparently very locally naturalised in New South Wales (Australia).

Ecology.

Grows in disturbed sites, along roadsides and field margins, on rocky, sandy or clay soils; between (50-) 1,400 and 3,000 (-3,700) m in its native range, near sea level in Australia.

Common names.

None recorded for the Old World.

Uses.

None recorded for the Old World.

Preliminary conservation status

( IUCN 2016). Solanum palitans is a widespread species in its native range, has a relatively large EOO across its entire distribution and can hence be assigned a preliminary status of LC (Least Concern; Table 7 ). It is only locally established in coastal New South Wales. The preliminary assessment based on South American distribution is still LC based on EOO (898,907 km2).

Discussion.

Solanum palitans is distinct amongst the species of morelloids occurring in the Old World in its combination of uniformly 3-lobed, thin membranous leaves and pale yellow mature fruits. The species has a creeping habit, with stems growing close to the ground extending up to 3 m and often rooting at nodes. Outside of its native range in South America, it is only found in Australia, but may appear in other areas of suitable habitat given time. Details of its variability and habitats in Argentina can be found in Morton (1976) and Barboza et al. (2013).

Like other adventive members of this group, it is likely to have been introduced to Australia with wool waste from Argentina. The first collection cited in Symon (1981) is from 1911 and the most recent we have seen is from 2013. It appears not to be spreading from New South Wales, but could also occur in New Zealand due to habitat similarities, although we have seen no specimens of S. palitans from there. Symon (1981) records that it is not eaten by stock, perhaps accounting for its limited distribution.

Selected specimens examined.

Australia. New South Wales: Barallier via Moss Vale, May 1950, Carlon s.n. (NSW); Burragorang Lookout, 14 mi S of Yerranderie, 17 mi WNW of Bowral, 23 Mar 1966, Constable 6738 (CANB, K); Wingecarribee, 39 km WNW of Mittagong, 16 Mar 1975, Coveny et al. 6089 (AD, NSW); Tamworth Regional, Moorsville, The Forest , S of Moore Creek, 4 Sep 1996, Hosking 1282 (CANB, MEL, NS, NSW); Campbelltown, Showground, 26 Apr 1964, McBarron, 9021 (AD, NSW); Armidale Dumaresq, Hillgrove mine, S of Hillgrove, 15 Oct 2014, Without collector 16 (NE) .

Figures

Figure 31. Solanum palitans A Habit B Flower C Anther D Gynoecium E Fruit (A-F Cabrera 13875). Drawing by Drawing by M. T. Cabrera, first published in Flora de Jujuy (1983), courtesy of the Board of the Instituto Darwinion (San Isidro, Buenos Aires, Argentina), reproduced with permission.

Figure 32. Solanum palitans A Habit B Leaves C Flowers and inflorescence D Fruits at different stages of maturity (A-D Barboza et al. 3471). Photos by Tiina Saerkinen.

Figure 33. Distribution of Solanum palitans in its non-native range in the Old World.