Solanum coalitum S. Knapp, Novon 17: 212. 2007

Knapp, Sandra, 2013, A revision of the Dulcamaroid Clade of Solanum L. (Solanaceae), PhytoKeys 22, pp. 1-432 : 78-82

10. Solanum coalitum S. Knapp, Novon 17: 212. 2007 Figure 26

Type.

Ecuador. Loja: Yangana-Valladolid, km 1.1, track to Sierra Toledo, km 18.5, 3250 m, c. 4°23'S, 79°06'W, 14 Nov 1997, G. Lewis & B. Klitgaard 3719 (holotype: LOJA; isotypes: AAU, BM [BM000846493], K [K000585495], NY [NY00888405], QCA, QCNE [QCNE-740]).

Description.

Subshrubs to 1 m tall, sometimes scandent and trailing. Stems glabrous and shining, usually appearing warty from the prominent leaf scars; young stems and leaves completely glabrous or sometimes with a few scattered loose white branched trichomes to 0.5 mm long. Bark of older stems dark brown, shining. Sympodial units plurifoliate. Leaves simple, 2.5-10.4 cm long, 0.7-3.5 cm wide, narrowly elliptic to less commonly elliptic, the upper surfaces glabrous and shiny, sometimes with scattered branched trichomes at the edge where the margin is revolute, the lower surfaces glabrous or sparsely papillate, the papillae drying reddish brown, perhaps glandular; primary veins 5-10 pairs, drying darker than the lamina; base acute to attenuate; margins strongly revolute, pubescent on the upper surfaces where turned under; apex acute; petiole 0.3-1.6 cm long, glabrous and shiny. Inflorescences terminal, 2.5-6 (-10) cm long, branched 4-6 times, with 3-15(-20) flowers, glabrous and shining, or with scattered loosely branched trichomes along the axes; peduncle 2-5.5 cm long; pedicels in flower 0.8-1.3 cm long, stoutish, ca. 1 mm in diameter at the base, ca. 2 mm in diameter at the apex, nodding, glabrous, minutely papillate or sparsely pubescent with loosely branched white trichomes ca. 0.3 mm long, articulated at the base and inserted in a short sleeve ca. 1 mm long; pedicel scars closely spaced and clustered at inflorescence branch tips. Buds globose when very young, soon elliptic and strongly exerted from the calyx tube. Flowers all perfect, 5-merous. Calyx tube 2.5-4 mm long, cup-shaped, strongly constricted at the base, thick and coriaceous, glabrous or with a few branched trichomes like those of the inflorescence axis, the lobes 1-1.5 mm long, broadly deltate or minute, glabrous, with the margins glabrous or densely pubescent with branched trichomes ca. 0.3 mm long. Corolla 2-2.6 cm in diameter, violet to dark mauve-purple, lobed 3/4 of the way to the base, stellate, the lobes 0.9-1.3 mm long, 0.5-0.8 cm wide, slightly campanulate or planar at anthesis, densely pubescent with simple or dendritic trichomes ca. 0.5 mm long on the margins and tips, sometimes with scattered simple trichomes on the abaxial lobe surface, these denser on the petal midvein, the adaxial surface glabrous. Filament tube less than 0.5 mm long; free portion of the filaments 1-1.5 mm long, glabrous; anthers 5-6 mm long, 1.5-2 mm wide, loosely connivent, poricidal at the tips, the pores lengthening to slits with age. Ovary conical, glabrous; style 1-1.2 cm long, straight, glabrous; stigma clavate or 2-lobed, bright green (fide Lewis & Klitgaard 3719), the surface minutely papillate. Fruit a globose berry, 1.2-1.5 cm in diameter, shiny and black when mature, the pericarp thin; fruiting pedicels 2-2.2 cm long, 2-2.5 mm in diameter at the base, 2-3 mm in diameter at the apex, erect, thick and woody. Seeds ca. 10 per berry, 4-5 mm long, 3-4 mm wide, flattened reniform, reddish brown, the margins not enlarged, the surfaces minutely pitted, the testal cells sinuate in outline. Chromosome number unknown.

Distribution

( Figure 27 ). Endemic to Ecuador, only known from the páramo of Cerro Toledo S of Loja along the road leading to the Peruvian border, on ridges between the towns of Yangana and Valladolid, at 3150-3460 m in southwestern corner of Parque Nacional Podocarpus.

Ecology.

Páramos and forest edges.

Conservation status.

Critically Endangered (CR); EOO <100 km2 (CR) and AOO <10 km2 (LC). See Moat (2007) for explanation of measurements. Knapp (2007c) gave a preliminary conservation status of EN (endangered) or critically endangered for this species. The fact that Solanum coalitum occurs only within the boundaries of the Parque Nacional Podocarpus is good news for its ultimate protection and conservation, but its very restricted distribution in an isolated habitat means it certainly is of concern.

Discussion.

Solanum coalitum is a striking species with its large, fleshy bright purple flowers and black fruits. Some specimens of Solanum coalitum have been identified as Solanum stenophyllum , with which it is very similar. Solanum coalitum differs from Solanum stenophyllum in its subshrubby, sometimes trailing habit, its glabrous stems and leaves (except for the peculiar marginal trichome band), its cup-shaped (rather than conical) calyx and its slightly larger flowers that are glabrous abaxially. Trichomes of Solanum coalitum when they occur are looser and more openly dendritic than the almost echinoid trichomes that are distinctly yellowish of Solanum stenophyllum . The fruiting pedicels of Solanum stenophyllum appear to be nodding when fruit are mature, while those of Solanum coalitum are erect. Specimens of Solanum stenophyllum have been collected from the province of Loja (i.e., Jørgensen et al. 477, 1068, BM) from further north and at slightly lower (2600-3000 m) elevations than Solanum coalitum and in drier and/or degraded forests. Solanum stenophyllum grows as a shrub or small treelet, usually in disturbed situations. Some individuals of Solanum stenophyllum in southern Ecuador are very sparsely pubescent, but the conical calyx and yellowish closely branched trichomes serve to distinguish these plants.

Solanum coalitum is distinguished from the very similar Solanum imbaburense by its broadly deltate, rather than long triangular calyx lobes, and its leaves with sparsely papillate undersides.

The sole locality in which Solanum coalitum has been encountered is the páramo of Cerro Toledo in the extreme southwestern corner of Parque Nacional Podocarpus, one of the largest protected areas in Ecuador. Cerro Toledo is a mixed páramo of tussock grasses and shrubby vegetation on the divide of the Cordillera de Sabanillas; the area is a pathway used by local people to take cattle from one drainage to another, and as such has a medium level of disturbance ( Hofstede et al. 2002). Roads constructed by the military to allow access to radio towers have opened the area to others. Hofstede et al. (2002) suggest that the inhospitable nature of the climate in the region (wet, cold and windy) will limit human incursion on a large scale. Cerro Toledo is isolated from other páramo regions of southern Ecuador, and represents one of the southernmost extensions of the páramo habitat in the Andes ( Luteyn 1999).

Specimens examined.

Ecuador. Loja: Yangana, Cerro Toledo, ascending road from Yangana to Numbala toward the antennas. Area next to antennas at summit of cerro, 3400 m, 27 Mar 2005, Bohs et al. 3320 (BM, LOJA, QCNE); carretera Yangana-Toledo, 3420 m, 28 Dec 1988, Jaramillo 10606 (AAU); road from Yangana to Cerro Toledo, km 18-22 to antennas, 3460 m, 3 Nov 2000, Jørgensen et al. 2188 (BM, NY); Yangana-Cerro Toledo, páramo of Cerro Toledo, 3420 m, 28 Dec 1988, Jørgensen et al. (AAU, BM); Cerro Toledo, Parque Nacional Podocarpus, 3350 m, 1 Dec 1988, Madsen et al. 75641 (BM); Cerro Toledo, 2500 m, 30 Oct 1989, Madsen 86333 (BM); Cerro Toledo, E of Yangana, Parque Nacional Podocarpus, 3400 m, 26 Feb 1985, Øllgaard et al. 58162 (BM).

Figures

Figure 26. Solanum coalitum S. Knapp. (A, B drawn from Jorgensen 2188 C D drawn from G. Lewis photographs of Lewis 3179). Illustration by Bobbi Angell.

Figure 27. Distribution of Solanum coalitum S. Knapp.