Citation:
Encycl. Suppl. 3: 751. 1814.
Type:
Based on an unpublished illustration in the Sessé & Mociño collection.
Written by:
Knapp, S.
Habit:
Woody vine, often reaching into the canopy. Stems sparsely to densely pubescent with tangled, very weak simple uniseriate trichomes to 0.5 mm, some trichomes furcate or dendritic in more pubescent individuals; new growth sparsely to densely pubescent with simple and furcate uniseriate trichomes, these tangled and weak, ca. 0.5 mm long. Bark of older stems yellowish brown, glabrate, corky on very large stems (fide Nee 23735).
Sympodial structure:
Sympodial units plurifoliate.
Leaves:
Leaves usually simple, occasionally pinnatifid, especially on younger stems, (2.5-)4-10 x (1-)2-8 cm, elliptic to obovate, usually widest in the basal third, slightly thick and fleshy, the upper surfaces glabrous and shiny with the trichomes confined to the veins to uniformly pubescent on the veins and lamina with simple uniseriate trichomes to 0.5 mm, the lower surfaces glabrous or the pubescence similar to that of the upper surfaces, but the trichomes denser along the veins; primary veins 6-7 pairs, connected by a prominent marginal vein ca. 0.5 cm from the margin; base acute to truncate or very occasionally somewhat cordate; margins entire or with 1-2 pairs of basal lobes, the lobes 0.5-0.7 cm long, each with a petiolule to 0.4 cm; apex acuminate, often with an elongate tip; petioles to 5 cm, glabrous or pubescent like the stems and leaves, the trichomes denser on the channelled adaxial groove, twining to aid in climbing.
Inflorescences:
Inflorescences terminal or lateral, 7-20(+) cm, longer in fruit, many times branched, with up to 80 flowers, glabrous or pubescent with simple uniseriate and occasionally furcate trichomes like the stems; peduncle 1.5-5 cm; pedicels 1-1.6 cm, slender, ca. 1 mm in diameter at the base, 1-1.5 mm in diameter at the apex, deflexed or nodding at anthesis, glabrous or sparsely pubescent with simple uniseriate trichomes abaxially, minutely papillate adaxially, articulated at the base from a tiny sleeve, leaving a small peg on the inflorescence axis; pedicel scars irregularly spaced 5-10 mm apart.
Flowers:
Flowers all perfect, 5-merous. Buds globose and inflated with prominent angles at the petal margins, the corolla strongly exserted from the minute calyx tube long before anthesis. Calyx tube 1.5-2 mm, flattened to somewhat conical, the lobes < 0.5 mm, mere teeth on the rim of the tube, glabrous to sparsely pubescent with simple trichomes, these denser on the minute apices. Corolla (2-)2.5-4 cm in diameter, violet to deep purple, very showy, stellate-rotate, lobed ca. 2/3 of the way to the base, the lobes 0.9-1.5 x 0.6-0.7 cm, spreading to slightly cupped at anthesis, densely papillate all long the margins and on the cucullate tips, otherwise glabrous. Filament tube ca. 0.5 mm, the free portion of the filaments 1.5-3 mm, glabrous; anthers 4.5-5 x 3-3.5 mm, ellipsoid to almost globose, yellow, loosely connivent, the abaxial surfaces thickened and enlarged and the thecae not visible, drying papillate, poricidal at the tips, the pores not lengthening to slits with age; ovary glabrous; style 14-16 mm, glabrous; stigma small capitate, the surface minutely papillose.
Fruits:
Fruit a globose berry, 2-2.5 cm in diameter, bright red and juicy when ripe, the pericarp thin and shiny, glabrous; fruiting pedicels 1.5-2.5 cm, 1-1.5 mm in diameter at the base, hanging from the weight of the fruit; fruiting calyx a flattened plate.
Seeds:
Seeds ca. 20 per berry, 5-6 x 4-5 mm, flattened reniform, reddish brown or pale brown, in immature fruit the surfaces minutely pitted, in mature fruits the lateral testal cell walls prominent and giving the seed a hairy appearance, these to 1 mm long and creating a prominent wing around the seed, the testa cells rectangular in outline.
Distribution:
From central Mexico (Estado Colima) to Nicaragua, in deciduous and evergreen forests from almost sea level to 2100 m.
Phylogeny:
Solanum dulcamaroides is a member of the Dulcamaroid clade (sensu Weese & Bohs, 2007) with a vining habit, distinctive pedicel insertion points and large, open inflorescences. It has not yet been included in any molecular analyses.
References:
Nee, M. 1982. The new species of Solanum published by Dunal in the Encyclopedie Methodique, Botanique, Suppl. 3.
Taxon 31: 320-322.
Nee, M. 1993. Solanaceae II.
Flora de Veracruz 72: 1-158. Instituto de Ecología, Xalapa, Veracruz.
Weese, T.L. & L. Bohs 2007. A Three-Gene Phylogeny of the Genus Solanum (Solanaceae)
Syst. Bot. 32(2): 445-463.
Knapp, S. 2008. Typification of Solanum (Solanaceae) species described by Sessé and Mociño.
Anales del Jardín Botánico de Madrid 65: 7-23.
Taxonomic name:
Solanum dulcamaroides is a beautiful plant, with large, fleshy flowers and bright red fruits. It is one of the larger vining members of the Dulcamaroid clade, often growing well into the canopy of rainforests. Although it in some ways resembles S. dulcamara (as mentioned by Dunal, 1813), it can be easily distinguished from that species by its inflated, globose angular buds (rather than the turbinate buds of S. dulcamara) and the much larger flowers (to 4 cm in diameter). It also is somewhat similar morphologically to S. boldoense of Cuba (see Knapp, 2008 for a discussion of the mix-up associated with these two species in the collections of Sessé and Mociño) and the more widespread and commonly cultivated S. seaforthianum. Solanum dulcamaroides differs from both those species in its distinctive anther morphology, with the abaxial surface thickened so that the thecae are not visible and the anthers appear as small football-shaped structures, and with pores that do not markedly lengthen to slits with age. The filaments of S. dulcamaroides and S. boldoense are equal, while in S. seaforthianum one filament is longer than the rest. Solanum boldoense has the articulation point of the pedicels just below the base of the calyx tube, while the pedicels of both S. dulcamaroides and S. seaforthianum are articulated at the base from a small sleeve. Pinnatifid leaves are rare in flowering or fruiting specimens of S. dulcamaroides (see below) and S. boldoense, while they are common in S. seaforthianum.
Although very few specimens of S. dulcamaroides have pinnatifid leaves, Nee (1993) records that divided leaves are borne on lower parts of the plant, and that plants cultivated from seed first produced profoundly pinnatifid leaves and eventually produced only simple leaves once stems became flowering. This developmental transition from pinnatifid juvenile to simple adult leaves appears to be relatively common in the Dulcamaroid clade (see S. flaccidum), but is often not noticed as herbarium specimens are usually made only from the terminal portions of reproductive stems. From herbarium specimens, it is apparent that leaf size decreases as the stem makes the transition to the inflorescence.
Leaf pubescence varies considerably in S. dulcamaroides, as it does in many other members of the group. Some specimens (especially those from the west of Mexico) are densely pubescent, with some of the trichomes furcate or with a few branches, but the majority of the trichomes are simple. Other plants, among them the type of S. megalospermum (Williams et al. 41964), are almost entirely glabrous. Plants from Nicaragua have smaller flowers (to 2.5 cm in diameter) than do plants from Mexico, flowering collections of S. dulcamaroides from Guatemala are a priority to see if this is a simple cline or due rather to environmental differences.
The epithet “dulcamaroides” has long been attributed to M.-F. Dunal rather than J.L.M. Poiret, the editor of the supplement to Lamarck’s encyclopaedia (see Nee, 1982). While most of the 41 Solanum epithets published in the supplement are indeed attributable to Dunal, S. dulcamaroides has the diagnosis ascribed to Dunal, but the epithet was not, and was therefore probably coined by Poiret himself. Dunal later cites “S. dulcamaroides Poir.” in synonymy with his Solanum macrantherum, attributing the epithet “dulcamaroides” to Poiret only, thus indicating that Poiret did not use the epithet Dunal had wanted for this plant.
Solanum dulcamaroides was described based on an illustration seen by Dunal in the collection of original drawings done for the Sessé & Mociño expedition to Mexico and central America (see McVaugh, 2000) and on his own, unpublished illustration, now held in the collections at MPU. Material linked to this name was described by Sessé and Mociño as S. sarmentosum and S. nutans, and herbarium sheets linked with those names can be found in MA (see Knapp, 2008), duplicates of these are also held in G. An illustration in the Torner Collection of the Hunt Botanical Institute (accession number 6331.1503) that clearly shows the distinctive bud morphology of this species is probably a most appropriate choice as the lectotype of S. dulcamaroides. Epitype material certainly is held in MA amongst the collections of the Sessé & Mociño expedition.