Solanum sessilantherum Gouvea

Gouvêa, Yuri & Stehmann, João, 2019, A Revision of the Solanum asterophorum Species Group (subg. Leptostemonum), Systematic Botany 44 (1), pp. 210-232 : 229-231

4. Solanum sessilantherum Gouvea ˆ& Stehmann, Phytotaxa 288: 125. 2016. Figure 3 , A–E .

Type: Brazil. Rio de Janeiro: Campos dos Goytacazes, Espera Feliz , 21°50, 47 ̎ ʺS, 41°36, 29 ̎ ʺW, 22 m, 15 May 2015 (fl, fr), Gouvea ˆ& Falcao ~ 188 ( BHCB) (holotype: BHCB! [ BHCB038227 ]; isotypes: [ BM, RB]).

Shrubs up to 2 m, the branches erect; young stems terete, densely to moderately stellate-tomentose apically, becoming sparsely stellate-puberulent on the oldest parts of the young stems; the trichomes hyaline to brown-tinged, porrect, sessile to short-stalked, the stalks less than 0.1 mm long, multiseriate, the rays 4–8(–10), 1-celled, the midpoints poorly developed, 1- celled, often absent; some minute, subsessile, glandular trichomes usually present on youngest portion of the stem (hardly observable in poorly preserved material); moderately armed, the prickles 1.3–5.8 mm long, 1–4.5 mm wide at base, recurved, flattened, stramineous at base, usually becoming ferruginous towards the apex, with stellate trichomes like those of the stems, and some small, subsessile, glandular ones at base, the latter often drying dark; bark of older stems glabrescent, dark green to dark brown or blackish. Sympodial units difoliate, geminate, the leaves of a pair anisophyllous. Leaves lobed; the major leaves 12.5–22.5 cm long, 5.9–12.5 cm wide, elliptic to obovate; base cuneate, slightly decurrent, generally asymmetric; margins shallowly to deeply lobed, the lobes deltate, (1–)2–6 on each side, to 2 cm long and 3.2 cm at base; apex acute to acuminate; primary veins 6–10 pairs; the minor leaves 5.1–8.1 cm long, 2.4–5.1 cm wide; elliptic; base cuneate, symmetric or asymmetric; entire to shallowly lobed, the lobes deltate, 0–3 on each side; the apex acuminate to rounded; primary veins 5–6; major and minor leaves all coriaceous, shiny adaxially when fresh, slightly discolorous, drying dark green to dark brown above, and dark brown to grayish-brown beneath (with a metallic appearance); the adaxial surface sparsely to moderately stellate-tomentose, the epidermis always visible, the trichomes porrect, sessile to short-stalked, the stalks to 0.1 mm long, the rays (3–)4–8(–11), 1-celled, the midpoints 1-celled, poorly developed, usually obsolete, the more rayed trichomes (7–8(–11) rays) usually brown-tinged, sometimes multiradiate, usually denser along the veins, less often than the hyaline, less rayed ones (4–6 rays) on the remainder of surface; the abaxial surface moderately stellate-tomentose, the epidermis always visible, the trichomes like those of the adaxial leaf surface, these hyaline, frequently mixed with some brown-tinged ones; armed along the midrib and the primary veins above, and usually only on the midrib beneath, the prickles straight, flattened, 2.3–9 mm long, 0.6–3.1 mm wide at base, (0–)13–23 above, (0–)6–11 beneath; petiole of major leaves 1.2–2.5 cm, moderately stellatetomentose with trichomes like those of the stems, the prickles 0–5, straight to slightly curved; petiole of minor leaves 0.7–2 cm, sparsely stellate-puberulent to moderately stellatetomentose with stellate trichomes like those of the stems, the prickles 0–3. Inflorescence a reduced monochasial cyme, to 3.6 cm long, unbranched, leaf-opposed or nearly so, with (1–) 2–7 flowers, 1–2 flowers open at a time; inflorescence axis (peduncle plus rachis) sparsely to moderately stellatepuberulent, with trichomes like those of the stem, usually armed, (0–)1–7 prickles; peduncle nearly obsolete to 1.7 cm long; rachis to 1.9 cm, straight; pedicel insertion points generally unequally spaced, 1.5–6.2 mm apart, more widely spaced proximally, usually not overlapping, if so only the more distal ones; pedicels straight or nearly so, with the flower buds erect to spreading (horizontally disposed), 10.4–22 mm long at anthesis, distally geniculate, articulated at base, armed, moderately to sparsely stellate-tomentose, with trichomes like those of the stems. Flowers 5-merous, heterostylous; basal flowers long-styled and hermaphroditic, short-styled and functionally male flowers produced distally in the inflorescence (see Sexual Expression and Inflorescence). Calyx tube obconic, 3.4–5.8 mm long, moderately to densely stellatetomentose, with trichomes like those of the adaxial surface of leaves, armed or not, the prickles 0–35, usually dorsiventrally flattened and adpressed when dry, swollen at base when fresh; calyx lobes foliaceous, narrowly oblong, elliptic or lanceolate (often varying in the same flower), 2–9(–12.5) mm long, often unequal in length, 1.8–3.5 mm wide, the apex acuminate to rounded. Corolla 2.4–2.9 cm in diameter, white, stellate, with well-developed and wavy interpetalar tissue, lobed for 1/2 to 2/3 of its length, the lobes 7.8–9 mm long, 7.6–9.8 mm wide, almost rounded to deltoid, apiculate at the apex, moderately to densely stellate-tomentose along the whole length abaxially, the trichomes hyaline to brown-tinged, porrect to multiangulate, sessile to subsessile, the rays 4–12, tortuous, usually forming a crab-like shape rather than a circle, the midpoint poorly developed, sometimes with multiradiate (more than 12 rays) trichomes at the lobe tips, the adaxial surface moderately to densely stellate-tomentose at the apex with trichomes like those of the abaxial surface becoming gradually sparser towards the base, the basal half glabrous or nearly so, the lobe tips slightly cucullate, reflexed at anthesis. Stamens equal; filament tube 1.1–1.7 mm long; free portion of the filaments very reduced, to 0.5 mm long; anthers 7.1–9 mm long, 1.8–2.8 mm wide, apparently sessile with basal lobes embedded in the basal portion of the corolla tube, broadly lanceolate, sagittate at base, narrowed towards the apex, dehiscing by apical pores, connivent. Ovary short-cylindrical, convex at the apex, with some small glandular trichomes; style of long-styled flowers 10.1–11.4 mm long, white, cylindrical, usually gently curved distally, with some stellate trichomes at base, in shortstyled flowers the style 5–6.4 mm long, straight; stigma 0.8–1.17 mm long, sometimes bilobed at the apex, green, the surface papillose. Fruit an obloid to transversely ellipsoid berry (length to width ratio 5:6–2:3), 9.7–12.8 mm long, 14–17.6 mm wide, the pericarp smooth, glabrous, green to dark green with the apex pale green to whitish-green at maturity; fruiting pedicels 1.4–2.5 cm long, armed, with 0–3 prickles; fruiting calyx accrescent, covering 1/3–1/4 of the mature fruit, truncate at base (slightly concave around the pedicel especially in fresh material), the lobes 4–7.5 mm long, (4.7–) 7.8–11.5 mm wide at base. Seeds ca. 40–70 per berry, 4.1–5 mm long, 3.2–3.7 mm wide, flattened, reniform, stramineous at the edge, brown at the center. Chromosome number: not known. Figures 5 , 6 .

Habitat and Distribution —Known only from the Parque Estadual do Desengano and surroundings, in Rio de Janeiro State, Brazil ( Fig. 10 ). Solanum sessilantherum inhabits wet forest edges and grows in damp soil under indirect light; low elevations, from 22 to 450 m.

Phenology —Flowering specimens have been collected from September to May; fruiting specimens have been collected between November and June.

Preliminary Conservation Status —Data Deficient (DD); the number of georeferenced collections (1) and inaccurate locality assignments preclude the assessment ( IUCN 2016). Only 6 collections have been made in the last 38 yr, four of these within the P. E. Serra do Desengano and other two in a nearby forest fragment. This suggests that S. sessilantherum is a somewhat rare species, and efforts to increase our knowledge about its range and population status are a priority for an accurate conservation assessment.

Etymology —This specific epithet is a combination of the Latin terms “sessileʺ and “anther,ʺ referring to the very reduced filaments, which are completely adnate to the corolla tube giving the anthers a sessile appearance.

Additional Specimens Examined— Brazil. — RIO DE JANEIRO: Mun. Campos dos Goytacazes, Espera Feliz, espécime mantido sob cultivo no Museu de História Natural e Jardim Botanico ˆda UFMG, indiv´ıduo n° 616, 21°50, 47 ̎ ʺS, 41°36, 29 ̎ ʺW, 22 m, 15 May 2015 (fl, fr), Gouvˆea & Falc~ ao 187 ( BHCB); Mun. Santa Maria Madalena, Parque Estadual do Desengano, Fazenda Morumbeca do Imbé, na mata, 11 Sep 1999 (fl), dos Santos 420 ( RB); Trilha para Morumbeca do Imbé, parte média da trilha, antes do Riacho da Morumbeca à direita, 15 Jun 2000 (fr), dos Santos 565 ( BHCB, RFFP); Alto Imbé, picada para o Cruzeiro, 350–450 m, 24 Oct 2012 (fl), Bandeira et al. 142 ( BHCB, RB); Derrubadinha, 24 Nov 1977 (fl, fr), Mautone 460 ( JPB, RB).

Notes — Solanum sessilantherum can be distinguished from other members of the S. asterophorum species group by a suite of characters: its armed inflorescence axis ( Fig. 5D, B ), pedicels straight or nearly so, with the buds erect to horizontally spreading, relatively distantly spaced pedicel insertion points ( Fig. 5A, B ), apparently sessile anthers with inconspicuous filaments ( Fig. 5B ), obloid to transversely elliptic (length to width ratio 5:6–2:3) berries ( Fig. 5D ), and coriaceous leaves. Solanum sessilantherum is morphologically very similar to S. asterophorum (especially those specimens of S. asterophorum with sparser indumentum) in overall appearance. However, S. asterophorum can be distinguished from S. sessilantherum by its unarmed inflorescence axis, downwardly curved pedicels with the buds pointing down and the pedicel insertion points very closely and evenly spaced ( Fig. 1B, F ) making the inflorescence more congested.

Solanum sessilantherum has only been collected a few times and is known only from two localities, the Parque Estadual do Desengano, Rio de Janeiro State, and a very nearby forest fragment. The nearest collection of S. asterophorum is from the municipality Casimiro de Abreu, Rio de Janeiro State, about 100 km in a straight line to the southwest from the collection points of S. sessilantherum . The species of the group whose distribution is geographically nearest (but still not sympatric) to S. sessilantherum is S. piluliferum . These species can be easily distinguished; S. pilulifeum has a cupuliform calyx, congested inflorescences with closely spaced pedicel insertion points ( Fig. 2B ), and long stramineous to ochraceous trichomes whereas S. sessilantherum has conical calyces, laxer more open inflorescences with widely spaced and seemingly unpaired pedicel insertion points, and sessile hyaline to brown-tinged trichomes (see Fig. 5 ).

NAMES NOT VALIDLY PUBLISHED—

Solanum scaberrimum Dunal, Prodr. [A. P. de Candolle] 13(1):

349. 1852. Nom. nud. pro syn. S. asterophorum Dunal.

Solanum asterophorum Mart. var. melancholicum (Dunal) Bitter , nom. nud. in sched. (Blanchet 3473, G). This name was written by the German Solanaceae taxonomist Georg Bitter on the specimen of the lectotype of S. gomphoidellum and is an unpublished combination based on S. melancholicum (here recognized as a synonym of S. asterophorum ).

Figures

FIG. 3. Photo of type collection of Solanum igniferum (Y.F. Gouvˆea & J.R. Stehmann 164, BHCB). A. Habit; note the orange indumentum completely covering the stems, the forked branching typical of the group, and the plagiotropic branches unique to S. igniferum. B. Young inflorescence; note the pedicels straight or nearly so, with the buds erect to horizontally oriented. C. Mature inflorescence. D. Fruits.

FIG. 5. Photos of type collection of S. sessilantherum (Gouvˆea & Falc~ ao 188). A. Young inflorescence; note the straight pedicels with the buds erect to horizontally oriented. B. Mature inflorescence; see the anthers looking sessile and the armed inflorescence axis. C. Flower. D. Fruit; note its obloid shape.

FIG. 6. Scan of holotype of Solanum sessilantherum (Gouvˆea & Falc~ ao 188, BHCB [BHCB038227]).

FIG.10. Distribution of Solanum sessilantherum. Points of the originally non-georeferenced records were inferred and are here represented by a different symbol.

FIG. 1. Solanum asterophorum from Minas Gerais (Gouvˆea & Falc~ ao 192, BHCB). A. Flower. B. Young inflorescence; note the pedicels curved downwards with the buds pointing down and the pedicel insertion points very closely spaced. C. Habit. D. Fruit. E. Habit of S. asterophorum from Santa Teresa, Espirito Santo (Giacomin et al. 1214, BHCB); note the shiny aspect of the stem and leaves due to the very sparse indumentum. F. Young inflorescence. G. Fruits. Photo credit E: L. L. Giacomin.

FIG.2. Solanum piluliferum. A. Young plant; note the first trichotomous branching followed by dichotomous branching. B. Inflorescence; note the longstalked trichomes and the cupuliform calyx. C. Habit. D. Fruit. Photo credit D: L. Menini Neto.