Solanum trifolium, Dunalin

Tepe, EJ & Bohs, L, 2011, A revision of Solanum section Herpystichum, Systematic Botany 36 (4), pp. 1068-1087 : 1084-1085

10. SOLANUM TRIFOLIUM Dunalin DC. Prodr. 13(1): 68. 1852.

— TYPE: ECUADOR. “ In Peruviae provinciâ Huyaquil ,” 1804 (fl), H. Ruiz & J. Pavón s. n. (holotype: G–G00080145 [scan!]; photos of holotype [F neg. 8591]: F–651206!, MO–1691471!, NY!; isotypes: MA–747193!; possible isotype: G-DC–G00144594 [scan!]).

Herbaceous vine, terrestrial. Stems slender, sparsely pubescent with trichomes 0.2–0.5 mm long. Sympodial units plurifoliate. Leaves 3-pinnate, the blades 1–5 × 1–6.5 cm, chartaceous to slightly fleshy, pubescent adaxially with widely scattered, wide-diameter trichomes ca. 1 mm long, the pubescence on veins adaxially of slender trichomes like those of the stem, the pubescence more dense abaxially and of slender (typical) trichomes, the margins entire, ciliate with short, fine hairs, the rachis with short, dense pubescence with trichomes like those of the stems; lateral leaflets 0.4–3 × 0.4–3 cm, rounded, the base oblique, rounded to cuneate, the apex rounded to truncate, minutely apiculate, the petiolules 2–3 mm, with short, dense pubescence; apical leaflet 0.6–3.5 × 0.6–4 cm, rounded, the base cuneate, the apex rounded to truncate to emarginate, minutely apiculate, the petiolule 1–3 mm, with short, dense pubescence; petioles 0.5–13.5 cm, sparsely to moderately sand-punctate, with short, dense pubescence. Internodes 1.5– 10 cm. Inflorescences 2.5–6 cmlong, unbranched, extra-axillary, with 2–3 flowers, the axes sparsely pubescent; peduncle 1–2 cm, slender; rachis 0.5–4 cm; pedicels 15–60 mm in fruit and flower, slender, sparsely pubescent, spaced 5–15 mm apart. Calyx 1.5–2.5 mm, the tube 1.2–1.5 mm long, the lobes 1–1.2 × ca. 1 mm, deltoid, acute at tips, sparsely pubescent abaxially with short, slender hairs, more densely pubescent adaxially; fruiting calyx slightly accrescent, the lobes ca. 2 × 2 mm. Corolla ca. 1.5 cmindiameter, 7.5–8 mm long, rotate, violet, the tube 5–9 mm, the lobes ca. 2.5 × 1.5 mm, acuminate at tips, glabrous abaxially, pubescent adaxially near the tips, the margins ciliate near the tips. Stamens with filaments 1–1.2 mm, glabrous; anthers 1–1.8 × ca. 1.2 mm. Ovary glabrous; style 3–3.5 × ca. 0.25 mm, clavate, papillose in middle; stigma capitate. Fruits 0.8–1 × 0.7–0.8 cm, ovoiddeltoid, flattened, pointed at apex, the color unknown, glabrous. Seeds ca. 2 mm in diameter, lenticular, the color and surface unknown. Figure 1D .

Habitat and Distribution— Solanum trifolium is endemic to Ecuador and is only known from the western slopes of the Andes in Bolívar Province; 2,600 –3,000 m in elevation ( Fig. 9 ).

Phenology— Flowering specimens have been collected in Feb., May, and Sept. to Nov. Fruiting specimens have been collected in Feb.

Conservation Status— According to the IUCN red list categories ( IUCN 2010), S. trifolium is classified as D2 (vulnerable). The nine known collections of this species are from two to three closely clustered localities within a narrow elevational band (2,500 –3,000 m) between San José de Chimbo and Chillanes, Bolívar Province, Ecuador. Solanum trifolium appears to be well suited to the disturbed habitats in the area, and has been collected in disturbed forest fragments, along roadsides, and in cow pastures. Nevertheless, it seems prudent to list it as vulnerable, because of the extremely narrow distribution of this species.

Etymology— The epithet trifolium refers to the 3-foliate compound leaves, and their striking similarity in size and shape to the leaves of some species in the genus Trifolium L. ( Fabaceae ).

Notes— Solanum trifolium , a ground-trailing species, is the only species in sect. Herpystichum with compound leaves and rotate flowers. The other two species with compound leaves, S. pentaphyllum and S. phaseoloides , both have stellate flowers, and the only other species with rotate or rotate-stellate flowers is S. dalibardiforme , which has simple leaves.

Dunal’s (1852) protologue lists a specimen in “h. Lambert et Boiss.”, and the Boissier herbarium is now held at G. A specimen at G-BOIS is labeled “ Solanum trifolium Dun. ! in DC Prodr.” in Dunal’s hand, and this is interpreted as the holotype. Apresumed duplicate of this collection exists at MA, but does not have Dunal’s annotation. It is interpreted as an isotype. Both specimens have “Fl. H. no. 449” on the labels, which has been interpreted by some as a collection number; however, the number refers to description No. 449 in a manuscript by J. A. Manzanilla (of S. ternatum , the original determination of Ruiz and Pavón’s collection), which has only recently been published in Tafalla’s Flora Huayaquilensis ( Tafalla and Estrella 1989). Another possible isotype exists at G. This sterile specimen was found in the DC herbarium, but with no associated collection information.

Additional Specimens Examined— ECUADOR. Bolívar: Chillanes, Urcu-corral, 2,600 –3,000 m, 3 Nov 1943 (fl), M. Acosta Solís 6594 (F); Road Chimbo-Babahoyo, 12 km from Chimbo, 1°43’S 79°06’W, 2,800 m, 3 Nov 1983 (fl), B. Boysen Larsen 45527 ( AAU); Chillanes, Crecit in lugares sombríos silvestres interandinos pueblo Atenas et Chillanes, Sep 1881 (infl), L. Sodiro /121 ( QPLS); Crecit in silvis inter Atenas et Chillanes, Prov. Riobamba, 1881 (infl), L. Sodiro 336 /11 ( QPLS); in Quebrada Lanszi, ca. 1 km Eof rd from La Magdalena to Balsapamba, 01°39’S 79°06’W, 2,820 m, 12 May 1991 (fl), D. M. Spooner et al. 5073 ( NY); in Andibus, 1857 (fl, fr), R. Spruce 5535 (C, E, G, GH, GOET, P, NY, S, W); Magdalena- Balzapamba road, ca. 5 km Wof Magdalena, 1°40′36”S 79°06′15″W, 2,800 m, 2 Feb 2009 (fl, fr), E. J. Tepe & S. Stern 2684 (MU, QCNE, UT); Rivulet NE of Chillanes, 2,500, Sep-Oct 1995 (fl), M. Weigend & S. Horn 3820 ( QCA).

Figures

FIG.1. Flowers fruits, and habit of Solanum sect. Herpystichum: A. Solanum limoncochaense, habit, flower, and bud. B. S. limoncochaense fruit in situ and C. in cross section (E. J. Tepe & S. Stern 2627, QCNE). D. S. trifolium flower and leaf (E. J. Tepe & S. Stern 2682, QCNE). E. S. phaseoloides habit, flower, and leaf (photo by W. H. Haber). F. S. crassinervium habit (E. J. Tepe & S. Stern 2729, QCNE), and G. flowers (S. Stern & E. J. Tepe 400, QCNE). H. S. evolvulifolium habit and flower, and I. fruit (immature) (E. J. Tepe & S. Stern 2671, QCNE). J. S. pacificum inflorescence with flowers, buds, and fruit (immature), and K. habit (E. J. Tepe et al. 2696, QCNE). L. S. loxophyllum habit, note adventitious roots at nodes, and M. older stem with inflorescences, note figure eightshaped stem (E. J. Tepe & S. Stern 2726, QCNE). Inflorescences emerge from the cleft between the two lobes of the stem.

FIG.9. Distribution of Solanum phaseoloides and S. trifolium.