Citation:
Revis. Argentine Sp. Solanum 92. 1976
Type:
ARGENTINA. Tucumán: Dept. Tafí del Valle, Yerba Buena, 19 Jan 1919, S. Venturi 159 (holotype: US [US00027724]; isotypes: BA [BA2463], LIL [LIL001454], LP [LP010926], MA, SI [SI003329]).
Written by:
Tiina Särkinen, Peter Poczai, Gloria E. Barboza, Gerard M. van der Werden, Maria Baden and Sandra Knapp
Habit:
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 structure:
Sympodial units difoliate, the leaves not geminate.
Leaves:
Leaves simple, 2.5–9 cm long, 2.5-7.5 cm wide, broadly ovate, thinly membraneous, 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. the base.
Inflorescences:
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:
Flowers 5-merous, all perfect. Calyx tube 1.5-2 mm long, cupshaped, the lobes ca. 0.75-1.5 mm long, lanceolate-oblong, 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, exserted 0.5-0.8 mm beyond anthers; stigma capitate, the surface minutely papillate, green in live plants.
Fruits:
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, tube 2-3 mm long, lobes 2-3(-4) mm long, covering the basal 1/3 of the berry, the lobe tips somewhat recurved.
Seeds:
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.
Phenology:
Mostly flowering and fruiting in the rainy season, from December through May, but occasionally found at other times of the year, in situations where water is available in weedy habitats near villages.
from Sarkinen et al. 2018 (https://phytokeys.pensoft.net/article/21991/): Solanum palitans is distinct among the species of morelloids occurring in the Old World in its combination of uniformly 3-lobed, thinly membraneous 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.
Solanum palitans is very easily confused in the herbarium with the sympatric S. tripartitum Dunal, and the species are mixed under the same collection number in several cases. In the field they are easily distinct, but even here it is easy to confuse them (but see key below) and there are apparently hybrids, at least in Bolivia. In Achumani, a suburb of the city of La Paz, Bolivia, forty individual plants were selected more at less at random from an area of ruderal vegetation on dry rocky slopes and gravelly stream beds; 25 proved to be S. tripartitum (Nee 32057a–y), 11 were S. palitans (Nee 32058a–k), and 4 seemed to be intermediate (Nee 32058a–d). The plants of Nee 32058a–d were similar to S. palitans, but had the branched inflorescences of S. tripartitum. Another possible hybrid was from Dpto. La Paz, Prov. Murillo, Valencia, 2 km NW of Mecapaca, in the arid valley of Río La Paz, 16°39’S, 68°02’W, 2950 m, 15 Feb 1987 (fl,fr), Nee & Solomon 34175 (LPB, NY).
Poorly prepared herbarium specimens and those in young flowering condition can be difficult to identify; mixed collections are common. In the field the two species are theoretically easy to distinguish by the characters of the following key, with S. tripartitum being an upright plant, the often decumbent base not rooting, and with erect and branched inflorescences; while S. palitans is a prostrate plant, rooting at the nodes, and with the simple inflorescences holding the fruit at the surface of the soil. The differential characters given in Morton (1976) are not necessarily reliable.
1. Plants decumbent or prostrate, often rooting at the lower nodes, forming a round patch, the branches to 1 m long, the young plants sometimes erect, nearly glabrous to sparsely pubescent in lines with simple hairs to 1 mm long; inflorescence a simple (rarely few-branched) racemose cyme, the peduncle 7–14 mm long, the rachis 4–15 mm long; flowers 4–9 per inflorescence; calyx 2–3 mm long in anthesis, lobed about half way into lanceolate-oblong lobes up to 1.5 x 0.9 mm, accrescent in fruit to 5 x 2.5 mm and covering the basal 1/3 of the berry; berry pale yellow-orange when ripe. Solanum palitans
1.Plants erect and with several branches or spreading to decumbent or even prostrate herbs, generally not rooting even where in contact with the soil, but sometimes rooting at the lowermost nodes, completely glabrous to sparsely pubescent in short lines with simple hairs to 0.4 mm long from the ciliate lower margin of the petiole; inflorescence a 2–9-branched racemose cyme, glabrous or rarely minutely puberulent, the peduncle ca. 10 mm long, the rachises 1–4 cm long, the flowers numerous; calyx 2–2.5 mm long in anthesis, often somewhat swollen at the base, lobed about 1/3 to base into triangular, obtuse lobes ca. 1 x 1 mm, barely accrescent in fruit to 1.5 mm long and not covering the base of the berry; berry passing from green to orange to red when fully ripe.
Solanum tripartitum