Solanum, Bitter

Stern, Stephen, Bohs, Lynn, Giacomin, Leandro, Stehmann, João & Knapp, Sandra, 2013, A Revision of Solanum Section Gonatotrichum, Systematic Botany 38 (2), pp. 470-496 : 474-476

SOLANUM section GONATOTRICHUM Bitter ,

Repert. Spec. Nov. Regni Veg. 11: 230. 1912.

—TYPE species: Solanum gonatotrichum Bitter (= Solanum turneroides Chodat ).

Herbs or shrubs, sometimes rhizomatous, lacking prickles. Stems nearly glabrous to densely pubescent with straight or geniculate, unbranched and/or stellate hairs. Leaves simple, the blades chartaceous to membranaceous, elliptic to elliptic-ovoid to cordiform, glabrous to densely pubescent with straight or geniculate, unbranched and/or stellate hairs, the base rounded to obtuse to truncate or cordate, often decurrent into petiole, the margins entire and often ciliate, the apex acute; petioles sparsely to densely pubescent. Inflorescence nearly sessile, extra-axillary or subopposite the leaves, unbranched, with 1– 6 (12) flowers, the axes sparsely to densely pubescent; pedicels articulated at the base. Flowers 5-merous, perfect, actinomorphic or zygomorphic due to heteranthery. Calyx campanulate to spreading, sparsely to densely pubescent, the lobes linearlanceolate to broadly triangular, erect to reflexed at anthesis, not to slightly accrescent in fruit. Corolla white to pale pink or purple, membranaceous, stellate to rotate with abundant interpetalar tissue, glabrous adaxially, glabrous to sparsely pubescent abaxially, mostly on apex and main veins. Stamens equal or one stamen borne on an elongated filament to twice the length of the others, the filaments short to greatly elongated, glabrous, inserted in corolla tube near its base; anthers connivent, yellow, sagittate at the base, poricidal at the tips, the pores directed distally, not (or rarely) opening into longitudinal slits. Ovary glabrous to sparsely pubescent; style equal to or exserted beyond stamens, cylindrical, glabrous, the stigma capitate. Fruit a globose to ovoid berry, obtuse at apex, glabrous, green to white or purplish-black when ripe, the pericarp thin, the mesocarp watery and held under pressure, dehiscing explosively at maturity. Seeds somewhat flattened, often with raised ridges on outer margin.

A KEY TO THE SPECIES Of SOLANUM SECTION GONATOTRICHUM

1. Plants usually woody (occasionally herbaceous), 0.5 – 1.5 m tall; hairs predominantly stellate; sympodia 3-foliate toplurifoliate; peduncle 3–8 mm ............................................................................. 5. S. lignescens Fernald

1 '. Plants herbaceous from a slightly woody base or woody in few cases ( S. hoffmanseggii ), 0.3 –0.6 (0.8) m tall; hairs simple; sympodia 2-foliate; peduncle absent or nearly so...................................................................... 2

2. Cauline hairs exclusively geniculate (bent at a 90 ° angle between first and second cells), at least on the older parts of the stems, and lying flat along stems................................................................................. 3

3. New growth densely pubescent with simple hairs, these lying flat along stem but lacking a strong 90 ° bend (see Figs. 1A, B ); corollas 1–2.5 cmin diameter, white to purple; flowers heterantherous with one filament longer than the rest, 2–5 mm long; mature fruits 10–20 mm in diameter, the fruit wall thickened at apex resultingindehiscenceatproximalendnearcalyx ...................................................... 8. S. turneroides Chodat

3 '. Hairs strictly geniculate with a strong 90 ° bend; corollas 0.5 – 1.3 (–1.5) cm in diameter, white; flowers homantherous or very weakly heterantherous (only faintly noticeable in live plants and barely visible in dried specimens), all filaments equal or nearly so, 1–2 mm long; mature fruits up to 12 mm in diameter, thefruitwallnotthickenedatapex ...................................................................................... 4

4. Plants subshrubs, 50– 80 cm tall; leaves lanceolate, more than three times longer than wide; plants of Amazonian Brazil (Pará and Tocantins) ........................................................ 4. S. hoffmanseggii Sendtn.

4 '. Plants herbaceous, rarely woody, often rhizomatous, under 40 cm tall; leaves elliptic to elliptic-ovate, less than three times longer than wide; widespread species of Paraguay, Argentina, Bolivia and thexericaxisof Brazil (Bahia, Goiásand Mato Grossodo Sul) .......................................... 7. S. olympicum Hassl .

2 '. Caulinehairsstraight, notgeniculate, andnotlyingflatalongstems ............................................................... 5

5. Corollas 1 –2.5 cm in diameter; flowers heterantherous with one filament longer than the rest, 2–5 mm long; maturefruits 10 –20 mmindiameter ..................................................................................... 6

6. Leaves typically 1.5 –3.5 (4) cm long; abaxial surface of calyx and pedicels with long multicellularglandularhairs (ca. 0.5 mmlong); plantsofeast-centralBahia, Brazil ........ 3. S. evolvuloides Giacomin & Stehmann

6 '. Leaves typically 3.5–8 cm long; abaxial surface of calyx and pedicels with exclusively eglandular hairs; plantsof Argentina, Bolivia, Paraguay, andBrazil (MatoGrossodoSulandSãoPaulo) ............. 8. S. turneroides Chodat

5 '. Corollas 1–1.7 cmin diameter; flowers homantherous, allfilaments equal, 1–2 mm long; maturefruits 5–12 mmindiameter ........... 7

7. Plants much-branched and spreading from a slightly woody base; leaves cordate, with small glandular hairs on both sides; plants of northeastern Argentina (Provs. Misiones and Corrientes) and southern Brazil (RioGrandedoSul) ....................................................................... 1. S. adscendens Sendtn.

7 '. Plants not or few-branched, the base typically not woody; leaves elliptic to elliptic-ovoid, the base rounded to obtuse, with exclusively eglandular hairs on both sides; plants of North and Central America and coastal Ecuador..................... 8

8. Plants arising from a single base, rarely rhizomatous; abaxial surface of leaves densely pubescent; seeds with swollen margins and a pronounced notch where connected to placenta; plants ofsouthwesternUSAandwidelydistributedfromMexicothroughCostaRica ....................... 2. S. deflexum Greenm.

8 '. Plants always rhizomatous; abaxial surface of leaves nearly glabrous to sparsely pubescent; seeds uniformly flattened throughout without a prominent notch where connected to placenta; plantsofcoastalEcuador ..................................................................... 6. S. manabiense S.Stern

Figures

FIG. 1. Scanning electron micrographs of hairs in section Gonatotrichum. A. Solanum turneroides stem; note the hairs oriented downward at an approximately 45° angle (Bohs 2715, UT). B. Higher magnification of S. turneroides; note that the base of the hair is swollen with what appear to be reduced ray cells. Also note the small glandular hairs below the long, simple hairs (Bohs 2715, UT). C. Stem of S. deflexum; note the hairs are simple and held perpendicular to the stem (Nee 51716, UT). D. Geniculate hairs of S. olympicum; note the sharp 90° angle between the first and second cells (Bohs 3194, UT). E. Stellate hairs on abaxial leaf surface of of S. lignescens (Hampshire et al. 1151, BM). F. Solanum evolvuloides glandular calyx hairs (Mattos Silva, s.n., CEPEC). Scale bars: A, C = 500 Mm. B = 50 Mm. D, E = 200 Mm. F = 100 Mm.