Solanum kriegeri Giacomin & Stehmann, 2014

Giacomin, Leandro L. & Stehmann, Joao R., 2014, Three new species of Solanum (Brevantherum Clade) endemic to the Brazilian Atlantic Forest, PhytoKeys 38, pp. 69-87 : 79-82

Solanum kriegeri Giacomin & Stehmann sp. nov. Figs 2D , 5

Diagnosis.

Differs from Solanum bradei Giacomin & Stehmann in its small shrub-like habit, its shiny leaves with extremely sparse pubescence, its sessile to subsessile inflorescences sometimes with a very short peduncle of up to 2 mm, and by its larger opaque fruit with more numerous seeds. Also differs from Solanum inornatum Witasek by having deltate, up to 2 mm calyx lobes.

Type.

BRAZIL. Minas Gerais: Parque Estadual da Serra do Ibitipoca, Proximidades da Lombada, 1650 m, 21°41'S, 43°53'W, 20 Jan 2005 (fl, fr), R.C. Forzza, L.C. Assis, L.M. Bezerra, M.F. Calió & L.G. Temponi 3959 (holotype: RB; isotypes: BHCB, BM).

Description.

Herbs to small shrubs up to 50 cm tall, woody at base, often with a single stem or few branches, these primarily erect, ascending, becoming arched and pendant. Stems sparsely to moderately pubescent with simple uniseriate trichomes up to 1 mm long, with 2-3 cells, normally curved and antrorse, rarely spreading, sometimes geniculate. Bark of older stems becoming whitish, exfoliating, almost completely glabrous, that of new growth greenish brown. Sympodial units plurifoliate, normally not geminate, but if so, with leaves differing in size and shape. Leaves simple, 1.5-7 × 0.5-2 cm, narrowly elliptic, chartaceous to slightly coriaceous, concolorous, drying notably shiny on both surfaces, glabrous to glabrescent on both surfaces with sparse simple trichomes up to 0.6 mm long, with up to 2 cells, these most common along the midrib; base attenuate, not decurrent onto petiole; margins entire, sparsely ciliate, with trichomes like those of the leaf veins, lying antrorsely parallel to the margin; apex acute; petioles 2-5 mm long, with pubescence similar to the stems; minor leaves, if present, 0.4-1.2 × 0.3-0.6 cm, elliptic-ovate to circular, the base rounded to obtuse, the apex rounded to acuminate, the petioles absent to 2 mm long; venation brochidodromous; midribs and secondary veins visible to the naked eye, the midrib prominent on both blade surfaces, the secondary veins prominent abaxially and impressed adaxially. Inflorescences sessile to subsessile, lateral or subopposite the leaves, unbranched cymes with 1-6 flowers, the axis with the same pubescence as that of the stems; peduncle 1-2 mm long; rachis normally absent or rarely up to 6 mm long; pedicels 4-6 mm long in flower, 6-12 mm in fruit, articulated at the base, spaced up to 2 mm apart. Calyx to 5 mm long, the lobes 1-2 mm long in flower, up to 4 mm long in fruit, ca. 1 mm wide, deltate, glabrous to glabrescent abaxially, with trichomes if present like those of the stems, adaxially densely pubescent with capitate glandular trichomes less than 1 mm long, with single-celled stalks and a multicellular head; calyx not accrescent in fruit. Corolla 6-10 mm in diameter, white, stellate, membranaceous, the lobes 3-5 × 2-3 mm, ovate-lanceolate, glabrous on both surfaces. Stamens 2-3 mm long, equal in length, the filaments ca. 1mm long; anthers 1-2 mm long, ca. 1mm wide, oblong, slightly connivent, yellow, the base rounded, the apex emarginate and poricidal, the subapical pores directed introrsely, not opening into longitudinal slits. Ovary glabrous; style white, 3-5 mm long, straight, cylindrical, the stigma light yellow to greenish, capitate. Fruit a globose berry 6-12 mm in diameter, dull green when ripe, drying dark, glabrous. Seeds 6-12 per fruit, 3-5 × 2-3 mm, slightly swollen, reniform, with a small hollow at hilum region; the seed surface undulate, the margins flattened.

Distribution.

Endemic to Brazil in southern Minas Gerais state, close to the border with Rio de Janeiro State, where it is known from two adjacent mountain ranges within the Mantiqueira region, Serra do Ibitipoca and Serra Negra ( Fig. 3 ). All known collections are from two conservation units, APA Serra da Mantiqueira and Parque Estadual do Ibitipoca.

Ecology.

Occasional to rare in the understory of well preserved dwarf cloud forests (Floresta Ombrófila Densa Altomontana; Veloso et al. 1991) and normally associated with sandy soils or quartzite outcrops, in elevations of about 1,500 to 1,900 meters above sea level. Although few flowers were produced in cultivation, crossing studies suggested this species is self-incompatible, like Solanum bradei .

Phenology.

Fertile specimens were collected between September and March. A flowering peak was observed between November and January and fully developed fruits were observed in January and March.

Etymology.

The epithet honors the Father Leopoldo Krieger, a Brazilian naturalist and founder of the CESJ herbarium (Juiz de Fora, Brazil), one of the most important collections in Minas Gerais state. In 1969, Dr. Krieger was hired as a Professor at Uni versidade Federal de Juiz de Fora, when he started collecting in the surrounding areas. His efforts at Serra do Ibitipoca led to the first collections of Solanum kriegeri . In herbarium sheets and in most databases, is common to find Krieger’s collections wrongly cited as "P.L. Krieger"; the “P” corresponds to the Portuguese word for Father (Padre) and not to a forename. Nevertheless we decided here to maintain the orthography used on individual labels in the cited material, noting with square brackets the common misuse of the “P.”.

Preliminary conservation status

(IUCN, 2013). Endangered (EN) B2 ab (iii, iv). The species is known from two localities that are about 30 km away from each other with six points available. The calculated EOO was of 34.3 km2 what would led to the Critically Endangered category while the AOO of 20 km2 led to Endangered. We have chosen here to assign it to Endangered, a less severe category for three reasons: the species occurs in more than one location, it is known from within a effectively protected area (Parque Estadual do Ibitipoca), and the other location where it is found is somewhat remote. Nevertheless, Solanum kriegeri is from a very specific habitat in well-preserved forest fragments and monitoring its populations is strongly recommended. In light of the deforestation pressure surrounding the areas where it is found, we surmise that it might be restricted to its few known localities.

Discussion.

Solanum kriegeri is most similar to Solanum bradei ; both have small, deltate calyx lobes (1-2 mm long). It is, however, a much smaller plant than Solanum bradei with glabrous or glabrescent leaves, with sparse trichomes normally restricted to the midrib and a sessile to subsessile inflorescence. Solanum kriegeri occasionally has geminate leaves, but not as frequently as in Solanum bradei and, when present, the minor leaves are very reduced and look like stipules. The fruits of Solanum kriegeri are also distinctive; they are larger than those of Solanum bradei (6-12 versus 4-7.8 mm) due to the seed size and number (6-12 versus 2-4 seeds per fruit respectively). Another good field character is the fruit aspect at maturity: dull green in Solanum kriegeri and shiny, and translucent (watery) in Solanum bradei . Besides the calyx morphology Solanum kriegeri can be readily distinguished from Solanum inornatum and Solanum friburgense by the glabrescent indument of its shiny chartaceous leaves, the only species of the group that presents such feature.

Solanum kriegeri inhabits a very specific vegetation type and was thought to be endemic to Serra do Ibitipoca until recently when it was found in a neighboring mountain range. It is associated with dwarf cloud forests that grow as islands in highland grassy areas on sandy soils, normally within quartzite matrices. These formations are normally not as shaded as the habitats in which other species of the group are found, and although the soil is more well-drained, the atmospheric humidity is quite similar. It is common to find Solanum kriegeri growing in Sphagnum L. ( Sphagnaceae ) mats in these environments.

Specimens examined.

BRAZIL. Minas Gerais: Mun. Lima Duarte. Parque Estadual do Ibitipoca, Lombada, 8 Mar 2006 (fl, fr), F.M. Ferreira et al. 1009 (CESJ); Parque Estadual da Serra do Ibitipoca, Mata próxima a Lagoa Seca, 1870 m, 21°40'S, 43°52'W, 24 Nov 2004 (fl), R.C. Forzza et al. 3710 (RB); Parque Estadual do Ibitipoca, Mata e campo ao lado do alojamento, 21 Nov 2006 (fl, fr), R.C. Forzza et al. 4322 (RB; BHCB); Conceição de Ibitipoca, Parque Florestal Estadual de Ibitipoca, Na mata, 29 Nov 1970 (fl), [P.]L. Krieger & C.C. Urbano 9355 (CESJ, RB); Serra de Ibitipoca, perto de mata de galeria, 1500 m, 2 Nov 1973 (fl), L. Krieger 13179 (CESJ); Parque Estadual do Ibitipoca, Na trilha de subida para a Lombada, 1623 m, 21°41'1"S, 43°52'24"W, 17 Mar 2009 (fl, fr), L.L. Giacomin et al. 770 (BHCB); Parque Estadual do Ibitipoca, Mata nebular entre Lombada e Lagoa Seca, 1650 m, 21°40'57"S, 43°52'34"W, 27 Oct 2004 (fl), B.R. Silva et al. 1369 (RB); Parque Estadual do Ibitipoca, Mata pluvial montana, 12 Nov 1987 (fl), H.C. Sousa s.n. (BHCB 14650; RB). Mun. Rio Preto. Serra Negra, Burro de Ouro, 1525 m, 21°58'09"S, 43°53'13"W, 17 Oct 2011 (fl), L.L. Giacomin et al. 1642 (BHCB, BM, RB, UT); Serra Negra, Fragmento de floresta ombrófila altomontana anexa ao Pico das Três Divisas, 1601 m, 21°57'54"S, 43°52'57"W, 17 Oct 2011 (fl), L.L. Giacomin et al. 1643 (BHCB, BM, UT).

Key to the species of the Solanum inornatum group

1	Herbs to shrubs, up to 1.8 m; stems glabrescent to densely pubescent, if pubescent most of the trichomes antrorse or apressed; calyx lobes deltate, up to 2 mm long, not accrescent in fruit	2
-	Herbs to small shrubs, up to 50 cm; stems hirsute, the trichomes spreading to patent (sometimes hispid) or unordered (pointing in several directions, never completely antrorse); calyx lobes linear-lanceolate, 3-5 mm long, accrescent in fruit	3
2	Leaves matte when dried, conspicuously pubescent; inflorescences always pedunculate, peduncles 2.2-10 mm long; abaxial calyx surface conspicuously pubescent; fruits translucent green at maturity, 4-7.8 mm in diameter	Solanum bradei Giacomin & Stehmann
-	Leaves shiny when dried, glabrescent, with sparse trichomes mainly along midrib; inflorescences sessile to subsessile, with peduncles up to 2 mm long; abaxial calyx surface glabrescent; fruits dull green at maturity, 6-12 mm in diameter	Solanum kriegeri Giacomin & Stehmann
3	Sympodial units 2-foliate; leaves elliptic with attenuate bases and cuspidate apices; leaves with trichomes concentrated on veins of any order; calyx lobes strongly recurved at anthesis	Solanum friburgense Giacomin & Stehmann
-	Sympodial units 3-plurifoliate; leaves ovate-elliptic with rounded to subcordate bases and attenuate apices; trichomes evenly distributed on veins and mesophyll; calyx lobes straight, not strongly recurved at anthesis	Solanum inornatum Witasek

Figures

Figure 2. Photographs of the species in the field. A-B Solanum bradei Giacomin & Stehmann A Shoot showing the anisophyllous sympodia and lateral emergence of the inflorescence [from Hattori et al. 914 (BHCB)] B Translucent fruit [from Agra et al. 7398 (BHCB, JPB)] C Inflorescence of Solanum friburgense Giacomin & Stehmann in cultivation showing its hispid indumentum [from Giacomin 940 (BHCB)] D Inflorescence of Solanum kriegeri Giacomin & Stehmann [from Giacomin et al. 770 (BHCB); photo by F. D. Gontijo]. Scale bars A = 2 cm; B-D = 1 cm.

Figure 3. Known distribution of Solanum bradei Giacomin & Stehmann (circles), Solanum friburgense Giacomin & Stehmann (stars) and Solanum kriegeri Giacomin & Stehmann (triangles) in the states of Minas Gerais (MG), Rio de Janeiro (RJ) and Sao Paulo (SP) in southeastern Brazil.

Figure 5. Solanum kriegeri Giacomin & Stehmann. A Habit with detail of the typical indumentum B Subsessile inflorescence detail showing the very short peduncle C Corolla cross section showing stamens D Fruit with small calyx lobes E Seed. All from Giacomin et al. 770 (BHCB). Scale bars A = 10 cm; B and D = 1 cm; C = 5 mm; E = 2 mm. Drawings by B. Raddichi.