Solanum kollastrum Gouvea & Giacomin, 2018

Gouvea, Yuri Fernandes, Giacomin, Leandro Lacerda & tehmann, Joao Renato, 2018, A sticky and heavily armed new species of Solanum (Solanum subg. Leptostemonum, Solanaceae) from eastern Brazil, PhytoKeys 111, pp. 103-118 : 103

Solanum kollastrum Gouvea & Giacomin sp. nov. Figures 1 , 2 , 3 , 5

Diagnosis.

Differs from S. sublentum Hiern in its tomentose young stems, petioles and inflorescence axis with the indumentum composed of long-stalked (up to 1 cm) stellate-glandular trichomes with all rays glandular (versus pubescent-glandular indumentum composed of persistent simple glandular and persistent to early deciduous sessile to short-stalked stellate trichomes with only the midpoint glandular), in its straight stem prickles up to 17 mm long (versus recurved to oblique stem prickles up to 6 mm long) and in its large mature leaves 20.5-42 cm long and 20-38 cm wide (versus mature leaves 5.7-17 cm long and 3.8-14 cm wide).

Type.

Brazil. Minas Gerais: Ataléia, povoado de Canaã do Brasil, estrada não pavimentada que liga o município de Ouro Verde de Minas ao povoado de Canaã do Brasil, crescendo em área alterada próximo a afloramento rochoso gnáissico (inselberg ou pão de açucar), 18°00'19"S, 41°12'17"W, 313 m elev., June 2018 (fl, fr), Y.F Gouvêa 280 (holotype: BHCB [BHCB190863]; isotype: RB).

Description.

Shrubs up to 3.5 m, erect, moderately branched. Young stems terete, densely tomentose with hyaline to ochraceous stellate-glandular trichomes, these sessile to long-stalked with multiseriate stalks up to 1 cm long, multiangulate, the rays 5-20, 2-3-celled, unequal in length, all or almost all with a capitate glandular distal cell, the midpoint 2-3-celled, equal to or twice the length of the longest ray, the distal cell glandular; stems densely armed with prickles up to 17 mm long and to 2.3 mm wide at the base, straight, slightly flattened, stramineous to yellowish at base, becoming ferruginous towards the apex, pubescent with stellate trichomes like those of the stems and some small, stalked, uniseriate glandular trichomes at the base; bark of older stems greyish dark brown. Sympodial units difoliate to plurifoliate, the leaves not geminate, the leaves arranged in a 2/5 phyllotaxic spiral. Leaves simple, lobed, 20.5-42 cm long, 20-38 cm wide, the blade broadly elliptic to broadly ovate, membranous, discolorous, green adaxially and whitish light green abaxially when fresh, becoming dark green adaxially and light green to pale brown abaxially when dried; adaxial surface densely stellate-glandular tomentose but always visible, with multiangulate trichomes, these short- to long-stalked, with multiseriate stalks 3-4 cells wide, up to 1 mm long, the rays 4-11, 1-celled, all eglandular or with one or more glandular ones (then 2-3-celled), unequal in length, the midpoints 2-3-celled, usually longer than the rays, mixed with smaller porrect to antrorse, usually eglandular stellate trichomes, these sessile to short-stalked (stalks to 0.1 mm long), the rays 2-5, 1-celled and minute, inconspicuous, unbranched, subsessile uniseriate glandular trichomes; the abaxial surface densely stellate-glandular tomentose, the epidermis barely visible, with trichomes like those of the adaxial surface, but more densely distributed; sparsely to moderately armed along the midrib and the primary veins of both surfaces with straight, laterally compressed prickles reaching up to 10 mm long and to 1.3 mm wide at the base adaxially, up to 17.5 mm long and to 1.8 mm wide at the base abaxially; primary veins 5-7 pairs; base cordate, the two major basal lobes obtuse to rounded, 2.5-7 cm long at the longest point, often overlapping each other over the petiole, not decurrent on to the petiole; margins with the lateral lobes 1.5-4.8 cm long, 4-9 cm wide at base, acute or less often obtuse or rounded at the apex, both basal and lateral lobes sometimes with small secondary lobes; apex acute; petiole 4.5-19.5 cm, densely tomentose with trichomes like those of the stem, armed. Inflorescence a scorpioid cyme, usually unbranched, rarely forked or trifurcate, internodal or subopposite the leaves, the axis densely glandular tomentose with trichomes like those of the stem, but these hyaline to ochraceous, armed; peduncles 2.6-6 cm long, the rachis 4.3-11 cm long, with 11-35 flowers, with up to 3 open at the same time; pedicel insertions generally unequally spaced, adjacent to spaced 2.3 cm apart; pedicels 4.8-18 mm long in open flowers, straight, articulated at base, armed, densely tomentose with trichomes like those of the stem, but with the epidermis and trichomes often purple-coloured. Flowers 5-merous, the plants andromonoecious, producing hermaphroditic flowers (long-styled) and functionally male short-styled flowers, which vary in proportion (number of long- vs short-styled flowers) between inflorescences. Calyx somewhat urceolate, inflated, foliaceous, purple (mainly along the margins and apex of the calyx lobes) to green, armed, densely tomentose with the epidermis barely to not visible basally, becoming gradually more visible towards the apex of the lobes, with trichomes like those of the stem but these sometimes purple and with some eglandular rays; base rounded, markedly plicate on the fusion line at the base of the adjacent sepals, these basally concave, the calyx tube 4.5-8.2 mm long, 9.4-15.2 mm in diameter at the point with the largest diameter, the lobes 7.5-15.6 mm long, 6-9 mm wide at the base, triangular, the margins plane to strongly undulate and revolute, the apices acute to caudate. Corolla 2.3-3.9 cm in diameter, purple to lilac or bluish-lilac, stellate, lobed 2/5 to 1/2 of its length, interpetalar tissue absent, the tube 1.1-2.2 cm long, the lobes 10.9-15 mm long, 8.8-13.4 mm wide, deltate to triangular, the margins straight to slightly convex at base, the apex acute, apiculate or not, stellate-glandular tomentose abaxially with trichomes like those of the leaves, almost glabrous adaxially with trichomes sparsely distributed along the veins and near the apex. Stamens equal; filament tube 1-2.1 mm long; free portion of the filaments 1.3-2.9 mm long, glabrous; anthers 7.5-10 mm long, 2.8-4.3 mm wide, 2.4-2.9 mm thick at the widest point, slightly gibbous, broadly lanceolate, narrowed towards the apex, sagittate at base, connivent, with the pores directed to apex and slightly extrorse, the epidermis papillose, slightly swollen dorsally. Ovary conical to somewhat cupuliform, 4-lobed, 4-locular, densely stellate-glandular tomentose at the apex, becoming glabrous with age, the trichomes 2-7-rayed, stellate, sessile, with a 2-4-celled, eglandular or glandular midpoint longer than the 1-celled rays; style 13.7-15.9 mm long in long-styled flowers, 1.2-3.7 mm long in short-styled flowers, cylindrical, glabrous; stigma globose to clavate, up to 1.4 mm long in long-styled flowers, papillose, green when fresh. Infructescence axis up to 29 cm long. Fruit a widely depressed ovoid to obloid berry, 11.4-20 mm long, 12-22.5 mm wide, the pericarp smooth, pale green to white, with scattered stellate trichomes at the apex; fruiting pedicels 1.4-2.2 cm long, armed; fruiting calyx strongly accrescent, completely covering the fruit in all stages of development, the tube 16-20.4 mm long and 19-34 mm in diameter at the widest point, the lobes 11-21.8 long, 13.7-19 mm wide at base. Seeds ca. 230 per berry, ca. 2 mm long and 2.4 mm wide, flattened, reniform, dark brown. Chromosome number: not known.

Distribution.

Endemic to eastern Brazil (Figure 4 ). The known records of Solanum kollastrum are mostly concentrated along the Mucuri River watershed, ranging from the municipality of Ataléia, in northeastern Minas Gerais state, to Mucuri at the southern coast of Bahia. The only exception, so far, is one collection (J.G. Jardim et al. 3151; CEPEC, NY) made further north, in Caatiba, a municipality of the south-central region of Bahia State.

Ecology and habitat.

Solanum kollastrum inhabits the edge of small forest fragments, especially those at the base or on granitic outcrops (inselbergs), which are geological formations characterising the peculiar landscape of the type locality. Some populations were also found in disturbed sites near these rock outcrops, such as borders of unpaved roads and pastures. The restinga (herbaceous to arboreal vegetation growing along the Brazilian sandy coastal lowlands; Araújo 1992) is a most distinct environment in which S. kollastrum has been found [S.A. Mori et al. 10459 (CEPEC, NY), Y.F. Gouvêa 283 (BHCB) and Y.F. Gouvêa 284 (BHCB)]. In restinga formations, S. kollastrum was observed in open disturbed areas dominated by grasses and at the edge of forest fragments near the Mucuri River mouth in Bahia State (Fig. 4 ). The known S. kollastrum habitats vary from environments subject to periods of drought (e.g. the edge of small seasonal semi-deciduous forest fragments or vegetation islands on inselbergs) to constantly wetter environments, at the edge of the aforementioned coastal forests, where the climate is under a strong oceanic influence. Its observed elevational range is from sea level to about 900 m. Field observations as well as its anther morphology (i.e. poricidal dehiscence and the anthers’ robustness) suggest that its primary pollinators are medium- to large-sized bees (e.g. genus Ptiloglossa ) with buzzing behaviour ( Michener 1962, Buchmann 1983). Solanum kollastrum fruits hang outside (below) the foliage on long inflorescence axes and are enclosed until their maturity by an inflated Physalis -like calyx. This, along with the persistent green to white epicarp colour, the fleshy mesocarp, the numerous relatively small seeds and the release of a mild sweetish scent at fruit maturity are characteristics associated with fruits eaten by bats ( Van der Pijl 1972, Cooper et al. 1986, Charles-Dominique and Cockle 2001). Actually, several studies have shown the importance of the fruits of Solanum species in bat diets ( Marinho-Filho 1991, Passos et al. 2003, Zanon and dos Reis 2007, Mello et al. 2008a) and the role of bats as dispersal agents for Solanum species ( Uieda and Vasconcellos-Neto 1985, Iudica and Bonaccorso 1997, Galindo-Gonzáles et al. 2000, Mello et al. 2008b). Many other Solanum species also present such features (e.g. those here considered morphologically related to S. kollastrum ; see discussion). However, species-level studies on pollination or fruit dispersal of Brazilian Solanum species are virtually non-existent, although being fundamental to confirm and better understand the interactions between these species and their pollinators and dispersal agents.

Phenology.

Flowering specimens were found from April to November, when immature fruits were also observed, indicating that Solanum kollastrum may bloom throughout most of the year. Specimens with mature fruits were observed at the end of June.

Etymology.

The epithet kollastrum is derived from the Greek words for glue (κόλλα) and star (άστρον), referring to the notable stellate-glandular trichomes observed on the younger stems, petioles and inflorescence axis of this species.

Preliminary conservation status.

Endangered (EN) B2 a, b (ii, iii, iv); Extent of Occurrence (EOO) 32,626 km2 (NT); Area of Occupancy (AOO) 20 km2 (EN). Despite the relatively large EOO (>20,000 km2) of S. kollastrum , its small AOO (<500 km2), the few and disjunct collections, all outside protected areas and the vulnerability of its habitats, lead us to suggest it should be attributed an Endangered status ( IUCN 2017).

Additional specimen examined (paratypes).

BRAZIL. Bahia: Mun. Mucuri, Rodovia Mucuri/Nova Viçosa (BA-001), crescendo em área de restinga aberta alterada dominada por gramíneas à margem da rodovia, 18°02'08"S, 39°31'10"W, 3 m elev., June 2018 (fl, fr), Y.F. Gouvêa 283 (BHCB); a 4 km a W de Mucuri, Restinga, 13 September 1978 (fl), S.A. Mori et al. 10459 (CEPEC, NY); Mun. Nova Viçosa, Rodovia Mucuri/Nova Viçosa (BA-001), crescendo em borda de fragmento de restinga arbórea à margem da rodovia, 17°56'37"S, 39°26'54"W, 5 m elev., June 2018 (fl, fr), Y.F. Gouvêa 284 (BHCB); Mun. Caatiba, entrada para a cidade ca. 11 km de Itapetinga, rod. para Caatiba 31.2 km da BR-415, 14°59'48"S, 40°23'12"W, 427 m elev., 3 November 2000 (fl, fr), J.G. Jardim et al. 3151 (CEPEC, NY). Minas Gerais: Mun. Ataléia, estrada de terra que leva da BR-418 à comunidade Canaã, 17°56'34"S, 41°10'39"W, 382 m elev., 15 June 2014 (fl, fr), Y.F. Gouvêa et al. 102 (BHCB); Mun. Teófilo Otoni, Rodovia BR-418, crescendo à sombra entre rochas da base de afloramento rochoso gnáissico (inselberg ou pão de açúcar) à margem da rodovia, 17°54'33"S, 41°11'37"W, 225 m elev., June 2018 (fl, fr), Y.F. Gouvêa 281 (BHCB); Pedra da Boca, topo do inselberg, crescendo na borda de capão de mata, 17°55'44.18"S, 41°11'1.36"W, 911 m elev., 20 September 2015 (fl, fr), J.R. Stehmann et al. 6387 (BHCB); Mun. Carlos Chagas, Rodovia BR-418, crescendo em área alterada no entorno de afloramento rochoso gnáissico (inselberg ou pão de açúcar) próximo à margem da rodovia, 17°52'16"S, 41°02'07"W, 280 m elev., June 2018 (fl, fr), Y.F. Gouvêa 282 (BHCB); Rod. BR-418, km 112, base dos paredões rochosos, 11 April 1984 (fl, fr), G. Hatschbach 47806 (CEPEC, NY).

Figures

Figure 1. Line drawing of Solanum kollastrum. A habit with notably dense prickles, leaves lacking secondary lobes and internodal inflorescences B detail of the prickly inflorescence with a hermaphrodite flower at anthesis C detail of a dissected flower D detail of the fruits enclosed by the strongly accrescent fruiting calyces (with the uppermost fruiting calyx opened to expose the fruit) from Gouvea 102 (BHCB).

Figure 2. Solanum kollastrum. A plant habit B detail of stem prickles C young inflorescence (upper right corner: detail of a more developed inflorescence) D flowering calyx E a short-styled and a long-styled flower displaying the extremes of variation of corolla size and colour found in the species (here exhibited by flowers of the same inflorescence); also note the various degrees of anther curvature and location of the apical pores compared with the images F and G F long-styled flower (hermaphroditic) with extrorse pores and slightly outwardly curved apices G short-styled flower (functionally male) with extrorse pores and markedly outwardly curved apices H infructescence with details of the strongly accrescent fruiting calyces (one of which was dissected to show the fruit) and the mature fruit colour (left side: details of fruit shape; right side: detail of a dissected fruit showing the four locules, placentation, seed colour and shape). Scale bars: 1.2 m (A); 3 cm (B, C, H); 1.5 cm (D, F, G); 1.8 cm (E). Photographs by Y. F. Gouvea.

Figure 3. Detail of Solanum kollastrum indumentum. A trichomes composing the indumentum of the stems, petioles and inflorescence axis B indumentum of the adaxial leaf surface C Indumentum of the abaxial leaf surface D Trichomes composing the indumentum of the abaxial leaf surface. Scale bars: 6 mm (A); 5 mm (B); 3 mm (C); 1.5 mm (D). Photographs by Y. F. Gouvea

Figure 4. Distribution of Solanum kollastrum.

Figure 5. Habitats of Solanum kollastrum. A general view of the small village of Canaa do Brasil illustrating the typical landscapes of the type locality B a specimen growing in the soil amongst rocks at the base of an inselberg C general view of an area of altered restinga vegetation with the arrow pointing to a S. kollastrum specimen (upper right corner: detail of the distinct architecture of the specimens growing in this environment) D a specimen growing at the edge of a restinga forest fragment. Photographs by Y. F. Gouvea