Solanum insidiosum [Mart. ]

Solanum insidiosum

Citation author:

Mart.

Citation:

Flora 21: 79. 1848.

Type:

Brazil. Rio de Janeiro: Rio de Janeiro, in Monte Corcovado, Jan 1834, B. Luschnath s.n. (lectotype, BR, designated by Agra, 2004: 206; isolectotype, K).

Last edited by:

Knapp, S.

Written by:

Agra, M.F & S. Knapp

Habit:

Woody shrub 1.5-3 m, erect and much branched, armed; stems terete, sparsely prickly, the prickles 0.5-0.8(-1) cm, laterally flattened at the base, recurved and acute at the apex, reddish or brown, glabrous or with scattered stellate trichomes, the young stems tomentose, the trichomes porrect stellate, glandular or eglandular, sessile to subsessile, the midpoint reduced and unicellular, lateral rays 8-10, the trichomes ochraceous, older plants glabrescent; new growth densely stellate-pubescent; bark of older stems glabrescent and dark brown.

Sympodial structure:

Sympodial units plurifoliate.

Leaves:

Leaves simple, entire or shallowly lobed (especially in juvenile plants), 3-10 x 2-5.5 cm, elliptic, chartaceous, the upper surfaces sparsely tomentose to glabrescent adaxially, the trichomes stellate, glandular, sessile, ochraceous to rusty, the lower surfaces tomentose, the trichomes stellate, glandular, whitish to yellowish cream, when young the leaves densely prickly with yellow or reddish flattened prickles 0.5-0.8 cm, older leaves unarmed or the prickles confined to the petiole and basal 1/3 of the blade; base acute to rounded or attenuate; margins entire to 3-4-lobed or angulate; apex acute, apiculate or acuminate; petiole 1-3 cm, unarmed or armed with prickles like those of the young leaves, tomentose with stellate trichomes like those of the leaves.

Inflorescences:

Inflorescences leaf-opposed, 3-11 cm, branching 2-3 times, with 10-30 flowers, stellate-tomentose with trichomes like those of the stems and leaves, the peduncle 2-5.5 cm; pedicels 0.7-1 x 0.1 cm, lengthening in fruit, terete, rusty tomentose with trichomes like those of the stems, articulate at the base; pedicel scars slightly raised. Buds conical, the corolla partially exserted from the calyx.

Flowers:

Flowers heterostylous, the basal ones long-styled and perfect, distal ones short-styled and staminate, fewer than the perfect flowers; calyx tube 2-3 mm, campanulate, the calyx lobes 2.5-3 x 1-1.5 mm, triangular-lanceolate with acute apices, tomentose abaxially, the trichomes porrect stellate with a unicellular reduced midpoint, glabrous adaxially; corolla 2-2.5 cm in diameter, white or greenish, lobed ca. ¾ of the way to the base, the lobes 0.7-1.0 x 0.2-0.3 cm, linear-lanceolate, tomentose abaxially with glandular stellate trichomes, the pubescent similar on the adaxial face but the trichomes with larger rays; free portion of the filaments 1-2 mm, the filament tube minute, glabrous; anthers 5-7 mm, tapering, poricidal at the tips, the pores directed distally, not lengthening; ovary 1-2 mm in diameter, subglobose, hirsute, the trichomes porrect stellate, glandular, the midpoint 4-5 mm; style in perfect flowers 10-15 mm, in staminate flowers 5-6 mm, straight or slightly curved, glandular-puberulent in the basal 1/4; stigma ca. 1 mm, subcapitate (in perfect flowers).

Fruits:

Fruit a globose, mucilaginous berry, 1-2 cm in diameter, variegated green and yellow when young, maturing yellow, the pericarp coriaceous, densely glandular-pubescent, the trichomes stellate; fruiting pedicels 0.5-0.7 x 0.2-0.25 cm, woody and erect.

Seeds:

Seeds 4-4.2 x 3-3.5 mm, ca. 1 mm thick, flattened reniform to lenticular, the testa reticulate.

Distribution:

Eastern Brazil from Pernambuco and the Distrito Federal to Rio de Janeiro, in disturbed areas and forest margins in littoral forests, cerrados and restingas, in sandy or calcareous soils, from 500-1500 m.

Phenology:

Flowering specimens have been collected from January to April, July and October and December; fruiting material has been collected from January to June.

Phylogeny:

Solanum insidiosum is a member of the Leptostemonum clade (sensu Levin et al., 2006; Weese & Bohs, 2007) based on overall morphology, but its relationships have not yet been tested using molecular data. Whalen (1984) placed it in his S. erythrotrichum group, but with a question mark, indicating his uncertainty as to this placement. Agra (2004) places this species in her subsection Rhytidoandrum.

Commentary:

Solanum insidiosum, as delimited here, is a species of great morphological plasticity, principally in leaf shape, pubescence density and presence or absence of prickles. Leaf shape varies from ovate, ovate-lanceolate to lanceolate and decurrent on the petiole, margins vary from entire to lobed or angulate, and pubescence density is also quite variable, especially between juvenile and adult plants. Lobed-angulate leaf margins are found in the collections Luschnath s.n, Vautier 527, Sellow II,. Pirani et al. 3497, while other specimens such as Guillemin 977, Vautier 527 and Claussen 190 have lanceolate, entire leaves with very sparse pubescence.

The protologue for Solanum insidiosum cites several different localities (“florete in mense Januario in Monte Corcovado, propre Sebastianopolis” e “Taubaté in Prov. Paulina, Dec. florens”). The lectotype has been selected from specimens with these localities and bering the collection number 257 (as cited in the protologue). The BR sheet was selected from the several sheets available, as it bears the number 257 and the locality coincides with one of those in the protologue (“in Corcovado, Jan florens”). The two varieties of S. insidiosum described by Sendtner have also both been lectotypified with specimens corresponding to the description collected by the cited collectors, as definite evidence as to the sheet used by Sendtner was not found.

The original spelling of the specific epithet of Solanum lalandi is correctable to S. lalandei following Article 60.7, Ex. 15 of the International Code of Botanical Nomenclature (McNeill et al., 2006), as the epithet clearly honors the collector M. de Lalande.

Two sheets of Vautier 527 were found at P, necessitating the lectotypification of S.lalandei var. subexarmatum; the sheet chosen by Agra (2004) is the one in a better conservation state and that represented by F. neg. 39183 in many herbaria. The lectotype chosen (Agra, 2004) for S. lalandei var. leptacanthum, Claussen 190, was the first collection cited in the protologue, has an indication of the taxon on the sheet in Dunal’s hand, and is in a better state of conservation than the other collection cited, Gaudichaud 525.

References:

Whalen, M.D. 1984. Conspectus of species groups in Solanum subgenus Leptostemonum.
Gentes Herbarum 12 (4): 179-282.

Agra, M.F. 2004. Sinopse Taxonômica de Solanum sect. Erythrotrichum (Solanaceae).
Pages 192-211, in Rangel-Ch, J.O; Aguirre-C, J.; Andrade-C., M.G. & Giraldo-Cañas (Eds). Memorias octavo congreso Latinoamericano Y Segundo Colombiano de Botánica. Instituto de Ciencias Naturales.

Levin, R.A., N.R. Myers, & L. Bohs 2006. Phylogenetic relationships among the "spiny" solanums (Solanum subgenus Leptostemonum).
Amer. J. Bot. 93: 157-169.

Weese, T.L. & L. Bohs 2007. A Three-Gene Phylogeny of the Genus Solanum (Solanaceae)
Syst. Bot. 32(2): 445-463.

Solanaceae Source

A global taxonomic resource for the nightshade family

Solanaceae

Solanum insidiosum Mart.

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