Athenaea hunzikeriana I.M.C. Rodrigues & Stehmann, 2021

Rodrigues, Izabella Martins da Costa, Knapp, Sandra & Stehmann, Joao Renato, 2021, Two new species of Athenaea Sendtn. (Solanaceae) from the Atlantic forests of south-eastern Brazil, PhytoKeys 178, pp. 1-15 : 1

Athenaea hunzikeriana I.M.C. Rodrigues & Stehmann sp. nov. Figs 3 , 4 , 5

Diagnosis.

Similar to A. pogogena , but differing in the campanulate rather than inflated calyx and a subglobose (versus ovoid) fruit that is purplish-red when mature and pubescent with eglandular trichomes (versus green to yellow fruits with glandular trichomes).

Type.

Brazil Minas Gerais: Santa Maria do Salto, Fazenda Duas Barras , 16°24'45"S, 40°02'51"W, 817 m elev., 1 Nov 2013 (fl,fr), J.R. Stehmann, L.L. Giacomin, S. Knapp & L. Bohs 6328 (holotype: BHCB [acc. # 182684; duplicates to be distributed to BM, RB) .

Description.

Shrubs to small trees, up to 3 m tall; branching virgate and distally dichotomous. Stems rounded in cross-section, dark brown, tomentose with yellowish-brown, simple uniseriate trichomes, up to 2 mm long. Sympodial units difoliate, the leaves geminate, members of a pair markedly unequal. Leaves simple, alternate, elliptic to elliptic lanceolate, subcoriaceous, discolorous; blades of major leaves elliptic lanceolate, 8.7-16.4 cm long, 2.8-5 cm, 2.3-4.5 times longer than wide, the minor leaves elliptic to obelliptic 2.7-6.8 cm long, 1.3-3.2 cm wide, ca. 2.5 times longer than wide; abaxial and adaxial surfaces densely pubescent with 8-15-celled eglandular trichomes 0.5-2 mm long and scarce 1-celled glandular trichomes with usually 3-celled multicellular head; venation camptodromous and prominent abaxially, with 3-6 pairs of principal veins; base decurrent, the leaves appearing sessile or sub-sessile; margins entire and slightly revolute; apex acute to somewhat acuminate; petioles 0-0.8 cm long, densely pubescent with trichomes like those of the leaves. Inflorescences axillary, with 10-15 flowers along a distinct axis; rhachis 1.5-3.4 mm long; pedicels 0.6-2 cm long, erect to spreading, densely pubescent with simple uniseriate trichomes. Flower buds ovoid, white, densely glandular-pubescent. Flowers 5-merous, heteromorphic with long- and short-styled forms. Calyx 3.5-4.5 mm long, green, campanulate, densely pubescent, the tube ca. 2 mm long, the lobes 1.6-2.7 mm long, 0.8-1.4 mm wide, triangular, densely pubescent with 5-8-celled eglandular trichomes and longer 5-10-celled glandular trichomes with multicellular heads abaxially, sparsely pubescent with 4-8-celled glandular trichomes with multicellular heads adaxially, the lobe apices acute. Corolla 4.1-7.3 mm long, stellate, white with green and purple spots adaxially near the base, the tube 1.1-1.6 mm long, the lobes 3.4-5.6 mm long, 1.3-2.7 mm wide, lanceolate, covered with eglandular trichomes (3-4-celled) abaxially at the apex and 4-6-celled glandular trichomes with multicellular heads abaxially over the entire surface, adaxially with 3-5-celled glandular trichomes with unicellular heads. Stamens 5, equal, glabrous; filaments ca. 0.8 mm long, the stapet (basal extension of the filaments) ca. 0.6 mm long; anthers 1.4-1.9 mm long, 0.8-1 mm wide, oblong, yellowish-cream, slightly cordate at the base. Ovary ca. 0.6 mm long, subglobose, yellowish-cream, densely pubescent with glandular trichomes, surrounded by a yellowish-green nectary; styles heteromorphic, greenish-white, long styles 2.8-3 mm long, short styles ca. 2.2 mm long; stigma dilated, capitate, yellowish-white. Fruit a subglobose berry, ca. 12.6 mm long, 13.7 mm in diameter, green when immature, wine-red to purplish-red at maturity, the pericarp densely pubescent with simple, uniseriate 4-8-celled eglandular trichomes; fruiting calyx not accrescent, up to 1.8 times longer than in flower; fruiting pedicels 1.5-2 cm long, erect, enlarged at the apex, densely glandular-pubescent. Seeds ca. 6 per berry, 5.5-5.7 mm long, 3.8-4.0 mm wide, flattened-reniform, yellowish-brown, the testa minutely reticulate, foveolate, the embryo curved. Chromosome number: not known.

Etymology.

The specific epithet honours Ing. Armando Teodoro Hunziker (1919-2001), who dedicated his life to the study of the family Solanaceae in the Neotropics and whose mentorship formed a whole generation of Solanaceae workers.

Phenology.

Athenaea hunzikeriana flowers and fruits from August to November.

Distribution and habitat.

Athenaea hunzikeriana is endemic to Brazil and only known from the type locality, in north-eastern Minas Gerais State and in adjacent Bahia State. Athenaea hunzikeriana grows in the understorey of well-preserved remnants of wet Atlantic forests (Floresta Ombrófila Densa, Mata Atlântica; IBGE 2012), from 700 to 1000 m elevation.

Preliminary conservation assessment

( IUCN 2019). Data Deficient (DD). Just two populations of A. hunzikeriana are known, one growing in a private reserve (RPPN Fazenda Duas Barras), in the Municipality of Santa Maria do Salto, Minas Gerais and another in Fazenda Farofa in the Municipality of Boa Nova, Bahia. Although the locality in Bahia is well-protected, the extremely restricted range indicates the species is of some conservation concern.

Discussion.

Athenaea hunzikeriana is easily recognised by its purple, eglandular-pubescent mature fruits on erect or spreading pedicels, its large seeds and the distinctive inflorescences with a short but persistent axis. Other species of Athenaea have axillary fascicles, with no rhachis along which pedicel scars can be observed. This species is morphologically similar to and sympatric with A. pogogena , with which it shares almost all flower characteristics, but can be distinguished by its subglobose (versus conic or ovoid) berry and leaf pubescence of mostly eglandular trichomes with sparse minute glandular trichomes, rather than densely glandular pubescent leaves. Athenaea hunzikeriana is also vegetatively similar to A. anonacea Sendtn. and A. martiana Sendtn. in having pubescent leaves but is differentiated from both those species by its pubescent fruit and non-accrescent fruiting calyx. It is also sympatric with A. fasciculata but differs from that species in its conspicuous pubescence ( A. fasciculata is glabrous, see discussion of A. altoserranae above).

Additional specimens examined.

Brazil. Bahia: Boa Nova, Faz. Farofa (Dr. Mauro), estrada entre Boa Nova e Dario Meira , 24 Oct 2007 (fr), F.M. Ferreira 1641 (CEPEC) . Minas Gerais: Santa Maria do Salto, Fazenda Duas Barras , 23 Aug 2003 (fl, fr), J.A. Lombardi, J.R. Stehmann, R.C. Mota & L.G. Temponi 5447 (BHCB) .

Dichotomous key to the species of Athenaea

All of the species in this key occur in Brazil, their distribution can be found in Rodrigues et al. (2019); A. fasciculata is the only species that occurs outside of Brazil.

1	Leaves glabrous or with eglandular trichomes only	2
-	Leaves with glandular and eglandular trichomes	10
2	Leaves geminate, anisophyllous, usually sessile, with both surfaces hispid; fruiting calyx accrescent, the tip extending beyond the fruit length	Athenaea martiana Sendtn.
-	Leaves solitary or geminate, not anisophyllous, subssessile or petiolate, glabrous to variously pubescent on both surfaces; fruiting calyx not or sometimes only partially accrescent, with the tip reaching up to 1/3 of fruit length	3
3	Stems, leaves, pedicels and calyx glabrous; leaves in clusters at branch tips	4
-	Stems, leaves, pedicels and calyx variously pubescent; leaves evenly spaced along branches, not clustered at branch tips	5
4	Leaves solitary, obovate-lanceolate; calyx more than 4 mm long; corolla thick and fleshy, with purple spots; fruits yellowish-green when mature	Athenaea sellowiana (Sendtn.) I.M.C. Rodrigues & Stehmann
-	Leaves geminate, rarely solitary, elliptic to lanceolate; calyx less than 3.5 mm long; corolla not fleshy, with brownish spots; fruits dark brown when mature	A. altoserranae I.M.C. Rodrigues & Stehmann
5	Leaves variously pubescent on both surfaces; calyx lobes triangular and of equal size and shape; fruits globose or subglobose	6
-	Leaves pubescent on the adaxial surface, hirsute on the abaxial surface; calyx lobes of unequal size and variously subulate; fruits ovoid	Athenaea wettsteiniana (Witasek) I.M.C. Rodrigues & Stehmann
6	Leaves adaxially glabrescent, abaxially sparsely pubescent to tomentose; inflorescences with up to 12 flowers; fruiting calyx lobes equally divided	7
-	Leaves with both surfaces velvety pubescent; inflorescences generally with (6-) 13 to 26 flowers; fruiting calyx lobes unequally divided	Athenaea velutina (Sendtn.) D’Arcy
7	Stems, abaxial leaf surfaces, pedicels and calyx tomentose; leaves ovate-elliptic, drying black; calyx tube narrowly urceolate in floral buds; calyx (tube+lobes) more than 3.5 mm long at anthesis	Athenaea tomentosa (Sendtn.) I.M.C. Rodrigues & Stehmann
-	Stems, abaxial leaf surfaces, pedicels and calyx glabrescent to sparsely pubescent; leaves elliptic to lanceolate, drying pale green; calyx tube campanulate in floral buds; calyx (tube+lobes) up to 2.5 (-3) mm long at anthesis	8
8	Trichomes appressed, with broad bases and curved apices; calyx lobes with acute apices	Athenaea brasiliana Hunz.
-	Trichomes patent, straight or curly; calyx lobes with obtuse to acute apices or with short caudate projections	9
9	Leaves narrowly lanceolate (length/width ratio> 4.8); corolla pubescent abaxially; seeds ca. 10 per fruit	Athenaea angustifolia (Alm.- Lafetá) I.M.C. Rodrigues & Stehmann
-	Leaves elliptic, ovate to lanceolate (length/width ratio <4.5); corolla glabrescent or glabrous abaxially; seeds more than 31 per fruit	Athenaea fasciculata (Vell.) I.M.C. Rodrigues & Stehmann
10	Leaves sessile or subssessile; leaf apices acute; leaf bases decurrent; fruiting calyx not accrescent	11
-	Leaves long-petiolate, the petioles up to 9 cm long; leaf apices cuspidate, leaf bases attenuate; fruiting calyx accrescent	12
11	Stems dichotomously branching throughout, sometimes trichotomously branching; calyx lobes strongly unequal, with one or two longer than the others; fruits ovoid, glabrous, yellowish-green when mature	Athenaea anonacea Sendtn.
-	Stems dichotomously branching only distally; calyx lobes equal; fruits subglobose, pubescent, vinaceous purple when mature	Athenaea hunzikeriana I.M.C. Rodrigues & Stehmann
12	Calyx lobes with bases auriculate in flower and fruit; pedicels sparsely pubescent	Athenaea cuspidata Witasek
-	Calyx lobes with bases not auriculate or only slightly cordate in fruit; pedicels densely pubescent	13
13	Trichomes of unequal size, arranged in two levels over the entire plant surface, translucent white; fruits glabrous; seeds more than 60 per fruit	Athenaea picta (Mart.) Sendtn.
-	Trichomes of equal size, arranged in a single level over the entire plant surface, red-ferruginous; fruits pubescent; seeds up to 50 per fruit	Athenaea pogogena (Moric.) Sendtn.

Figures

Figure 3. Distribution map for Athenaea altoserranae I. M. C. Rodrigues & Stehmann (circles) and Athenaea hunzikeriana I. M. C. Rodrigues & Stehmann (triangles). Bahia = BA; Minas Gerais = MG; Sao Paulo = SP.

Figure 4. Athenaea hunzikeriana I. M. C. Rodrigues & Stehmann a fruit b stem showing reduced peduncle c branch with buds, flowers and fruits; illustrated from J. A. Lombardi et al. 5447 (BHCB) d flower e branch with buds and flowers; illustrated from J. R. Stehmann et al. 6328 (BHCB). Illustration by I. M. C. Rodrigues. Scale bars 1 cm.

Figure 5. Athenaea hunzikeriana I. M. C. Rodrigues & Stehmann in the field a-c J. R. Stehmann et al. 6328 d J. A. Lombardi et al. 5447 - All photographs by J. R. Stehmann.