Waltheria marielleae T.S.Coutinho & M.Alves, 2022

Silva Coutinho, Thales, Analia Sader, Mariela, Pedrosa-Harand, Andrea & Alves, Marccus, 2022, Waltheria marielleae (Byttnerioideae, Malvaceae), a new species from north-eastern Brazil supported by morphological and phylogenetic evidence, Plant Ecology and Evolution 155 (3), pp. 353-362 : 353

Waltheria marielleae T.S.Coutinho & M.Alves sp. nov.

Figs 2A-F , 3

Type.

BRAZIL • Pernambuco, Mun. Bonito, Reserva Municipal de Bonito ; 13 Jun. 2018; fl., fr.; T.S. Coutinho et al. 375; holotype: UFP; isotypes: BHCB [207616], CEN, EAC, HCDAL, HUEFS, JPB, MAC [0065667], MBM, RB, SPF, UFMT, VIES .

Diagnosis.

Waltheria marielleae resembles W. indica by the branch indumentum, narrowly triangular stipules, elliptic leaf blades, axillary inflorescences, and fan-plumose stigmas, but differs by the olive green to greyish-green leaf blades (vs greenish), larger and distylous flowers (vs smaller and homostylous flowers), acute calyx lobe apex (vs acuminate), and spatulate and eciliate petals (vs oblong and ciliate).

Description.

Herbs to shrubs 0.7-1.5 m tall. Branches terete, apically compressed, sericeous, trichomes stellate, sessile or subsessile, whitish; bark sparsely lenticellate, lenticels verrucose. Stipules 6.5-8 × 0.8-1 mm, narrowly triangular, base truncate, margins entire, sparsely ciliate, apex acuminate, adaxial surface pubescent, trichomes simple and stellate, sessile, abaxial surface pubescent, trichomes stellate, sessile; vein 1, conspicuous, prominent abaxially. Leaves simple, alternate, spirally arranged along the branches; petiole 1.0-2.5 cm long, terete to slightly flat, canaliculate, densely sericeous, trichomes similar to the branches; leaf blades chartaceous, discolorous, 4.2-9.0 × 1.5-4.6 cm, plane, elliptic, widely elliptic to lanceolate, base rounded, apex acute, margins serrate, teeth 1.5-3.0 × 0.3-0.5 mm, adaxial surface olive green to greyish-green, pubescent, abaxial cinereous, canescent, trichomes stellate, sessile; venation actinodromous, 7-9 pairs of secondary veins and 2 basal veins. Inflorescence cymose, axillary along the branches, short pedunculate, few-flowered; bracts 5-6 × 1.5-2.0 mm, apex 2-3-dentate; peduncle 0.4-1.4 cm long, sericeous. Flowers distylous, sessile or short-pedicellate, arranged in pairs; bracteoles 4, 6.0-6.5 × 1.0-1.5 mm, distinct, elliptic to narrowly elliptic, apex acute, entire to 2-3-fid, adaxial surface sericeous, trichomes stellate, abaxial surface with a layer of small and dense, canescent stellate trichomes and a layer of big and sparse, pilose stellate trichomes, sessile; veins 2-3, conspicuous. Calyx 5-merous, gamosepalous, 4.5-5.5 × 2.5-3.5 mm, campanulate, 10-ribbed, pubescent externally, trichomes stellate and 2-fid, sessile, glabrous internally, internally pubescent on the lobes, simple trichomes, lobes 2.8-3.0 × 1.1-1.2 mm, apex acute; 4-6 pairs of secondary veins; nectary ca 0.4 mm long, on the base of the internal surface. Corolla 5-merous, dialypetalous, pallid yellow, petals adnate to the staminal tube for ca 0.8 mm of the length, 6.0-7.5 × 2.0-2.2 mm, spatulate, adaxial surface pilose, trichomes simple, abaxial surface glabrous, apex rounded to slightly emarginate, eciliate. Stamens 5, partially connate into a staminal tube, papillate apically, dithecal, thecae parallel, dehiscence rimose. Carpel 1 and locule 1, ovary obovoid, sericeous, style 1, lateral, pubescent, trichomes stellate, sessile, stigma 1, penicillate, fan-plumose. Brevistylous form: stamens ca 6.5 mm long, staminal tube 2.0-2.5 × 0.8-1.0 mm, free filaments 3.1-3.5 mm long, anthers 1.1-1.2 mm long, gynoecium 2.0-3.5 mm long, ovary ca 1.2 × 0.8 mm, sericeous apically, style 1.5 mm long, stigma ca 1 × 1 mm. Longistylous form: stamens 4 mm long, staminal tube 3.2 × 1.2 mm, free filaments absent, anthers 1.1-1.4 mm long, gynoecium 6.2-6.5 mm long, ovary 0.5-1.1 × 0.9 mm, sericeous, style 4.2-4.5 mm long, stellate trichomes, stigma 1.1-1.2 × 1.1 mm, fan-plumose. Capsule 1, 2.0-2.5 × 1.2-1.8 mm, obpyramidal, chartaceous at the apex, membranous below, apex truncate, sericeous, trichomes stellate, restricted to the apex, dehiscence loculicidal from the base to the apex and through it; seed 1, 1.3-1.8 × 0.8-1.2 mm, obovoid, brown, glabrous, apex rounded.

Distribution and habitat.

Waltheria marielleae is endemic to Brazil and known only from the states of Alagoas and Pernambuco (Fig. 4 ). This species is associated to the Atlantic Forest domain, found in seasonal semideciduous forests, as well as in the Caatinga ( IBGE 2012), at elevations 300-700 m a.s.l.

Phenology.

The species was collected with flowers from June to October and from December to January, and with fruits from June to October and in December.

Etymology.

The specific epithet honours Marielle Franco, a sociologist and former Brazilian councilwoman who vehemently fought for social causes, including LGBTQI+ causes, a community that the first author is proud to be part of. Marielle Franco was cowardly murdered along with her driver Anderson Pedro Gomes in 2018, but her name remains alive in the memory of those who share her ideals.

IUCN conservation assessment.

According to IUCN ( 2019) criteria and based on its Area of Occurrence (AOO of 28 km2) and Extent of Occurrence (EOO of 10,797 km2), Waltheria marielleae is assessed as Endangered (EN, B2ab (ii, iii)). The Atlantic Forest domain in the state of Pernambuco, where most of the populations were found, is highly fragmented with isolated and irregularly shaped patches, which can lead to population isolation ( Trindade et al. 2008) and a decrease in the persistence of many species ( Scarano and Ceotto 2015). A few populations are within protected areas such as Reserva Municipal de Bonito (Pernambuco) and Reserva Biológica de Pedra Talhada (Alagoas), but others were recorded alongside roads and highways. In the Caatinga, Waltheria marielleae is not found in any protected area.

Additional material examined (paratypes).

BRAZIL - Alagoas • Quebrangulo, Pedra Talhada; 6 Jan. 1986; fl.; Lyra-Lemos & Esteves 1140; HUEFS [000132912], MAC • Quebrangulo, Reserva Biológica de Pedra Talhada; 11 Jun. 2011; fl.; Lyra-Lemos et al. 13296; MAC • Quebrangulo; 23 Oct. 2011; fl.; Santos & França 21; MAC • Quebrangulo; 1 Aug. 2014; fl.; Correio et al. 134; MAC • Quebrangulo; 16 Dec. 2014; fl.; Nusbaumer 4169; JPB, MAC, NY [3474771] • São Sebastião, Povoado Sucupira; 1 Dec. 2003; fl.; Bayma s.n.; MAC [19983]. - Pernambuco • Bonito; 17 Sep. 1997; fl.; Santos 49; PEUFR • Bonito, Parque da Reserva Municipal; 17 Sep. 1997; fl.; Espíndola 08; PEUFR • Bonito, Reserva Municipal de Bonito; 13 Jun. 2018; fl.; Coutinho et al. 376; BHCB, CEN, EAC, HCDAL, JPB, MBM, UFP, RB, SPF • Bonito, Fazenda Tudo Muito; 13 Jun. 2018; fl.; Coutinho et al. 382; UFP; Bonito, Reserva Municipal de Bonito; 12 Sep. 1995; fl.; Melo et al. 245; PEUFR • Garanhuns, Fazenda Serra Branca; 09°10 ’38” S 40°58 ’20” W; 23 Oct. 2010; fl.; Oliveira et al. 5128; IPA • s.loc., margem da estrada entre Baraúna e Jurema; 26 Jul. 1966; fl.; Andrade-Lima 66-4712; IPA • s.loc., estrada para Petrolina; 5 Sep. 1986; fl.; Freitas 26; PEUFR.

Morphological affinities

Waltheria marielleae is classified in W. sect. Waltheria according to Schumann (1886) due to the capsules with loculicidal dehiscence and glabrous seeds. In addition, the narrowed stipules (narrowly triangular) and stellate trichomes on the branches can be used to categorize the new species within this section. According to the informal classification proposed by Saunders (1995, unpubl.), W. marielleae is placed in W. subg. Waltheria sect. Waltheria by the capsule with chartaceous and truncate apex and apical dehiscence. Waltheria marielleae can be easily confused with W. indica , especially in herbaria specimens, due to the morphological characters indicated in the diagnosis and presented in Table 1 .

Waltheria marielleae is phylogenetically related to W. ackermanniana and they share the subshrub habit, ciliate stipules, discolorous leaves, bracteoles longer than the calyx, distylous flowers, spatulate petals, and capsule with chartaceous, sericeous apex. Waltheria marielleae , however, has sericeous branches with only stellate trichomes (vs strigose or pilose branches with stellate and glandular trichomes in W. ackermanniana ), adaxially pubescent leaves (vs scabrous), 6-6.5 mm long, elliptic to narrowly elliptic bracteoles (vs 8.5-11 mm long, linear), 2.8-3.0 mm long, acute calyx lobes (vs 3.8-4.0 mm long, acuminate), pallid yellow corolla (vs golden yellow or reddish-yellow), and eciliate petal apex (vs ciliate).

Waltheria marielleae also resembles W. rotundifolia by the greyish leaves, axillary and sessile to short pedunculate inflorescences, distylous flowers, calyx with acute lobe apex, and fan-plumose stigmas, but differs by the narrowly triangular stipules (vs linear), long-petiolate leaves (vs short-petiolate), discolorous leaf blades (vs concolorous), narrowly elliptic to elliptic bracteoles longer than the calyx, without glandular trichomes (vs linear to lanceolate, shorter than the calyx and with glandular trichomes), pallid yellow corolla (vs golden yellow), eciliate petal apex (vs ciliate), calyx 2.5-3.5 mm wide (vs 1.5-1.8 mm), capsule with sericeous apex and partial dehiscence (vs tomentose and total dehiscence).

Regarding its geographic distribution, W. marielleae was collected together with W. indica in Bonito (state of Pernambuco), but the latter is a pantropical species, occurring in all regions and phytogeographical domains in Brazil. Waltheria ackermanniana was previously recorded in the south-eastern (states of Minas Gerais and Rio de Janeiro) and north-eastern (states of Bahia and Pernambuco) regions ( Coutinho and Alves 2020), being now also recorded in the state of Alagoas (A.P. Fontana & P.M.G. Caxias 9836 (HPISF)). This species inhabits areas of Cerrado, Caatinga, and Atlantic Forest biomes. In the states of Alagoas and Pernambuco, where W. marielleae was recorded, W. ackermanniana occurs ca 180 km and 200 km from the municipalities of Quebrangulo and São Sebastião, respectively, where the new species was collected.

In Brazil, W. rotundifolia occurs only in the north-eastern region, in all states. Saunders and Dorr (2022) point out the occurrence of this species in the states of Minas Gerais and Rio de Janeiro, however, after an intense study of the botanical collections in Brazil and abroad, no specimen was found so that this data could not be validated. This species primarily inhabits caatinga vegetation, but in the state of Rio Grande do Norte, it was observed growing in restinga vegetation (savanna-like formation with beach sands deposited during the Quaternary, in areas above sea level that support scattered clumps of small trees, shrubs, herbs, and grasses ( Thomas and Barbosa 2008)), an environment where W. marielleae has not been recorded.

Key to the Waltheria species occurring in Alagoas and Pernambuco, Brazil

1.	Foliaceous stipules, rounded base; capsules with operculate dehiscence; verrucose seeds ( W. sect. Stegowaltheria )	2
-	Scarious stipules, truncate base; capsule with loculicidal dehiscence; smooth to slightly crenulate seeds ( W. sect. Waltheria )	3
2.	Prostrate herbs; distylous flowers	W. bracteosa
-	Erect herbs; homostylous flowers	W. operculata
3.	Sticky branches and leaves; leaf blade with acuminate apex	W. viscosissima
-	Non-sticky branches and leaves; leaf blade with acute, rounded, truncate, or emarginate apex	4
4.	Terminal inflorescences	5
-	Axillary inflorescences	6
5.	Xylopodium present; filiform stipules; capsule with total dehiscence	W. communis
-	Xylopodium absent; narrowly lanceolate stipules; capsule with partial dehiscence	W. cinerascens
6.	Homostylous flowers	W. indica
-	Distylous flowers	7
7.	Strigose or scabrous branches, stellate and glandular sessile trichomes	W. ackermanniana
-	Tomentose, sericeous, pilose, or pubescent branches, stellate trichomes, with or without glandular stalked trichomes	8
8.	Branches with glandular stalked trichomes; calyx with acuminate apex lobe; elongate-plumose stigmas	W. martii
-	Branches only with stellate trichomes or mixed with glandular sessile trichomes; calyx with acute apex lobe; fan-plumose stigmas	9
9.	Discolorous leaf blades; elliptic to narrowly elliptic bracteoles with stellate trichomes; capsules with sericeous apex	W. marielleae
-	Concolorous leaf blades; linear to lanceolate bracteoles with stellate and glandular trichomes; capsules with tomentose apex	W. rotundifolia

Figures

Figure 2. Waltheria marielleae (A-F), W. ackermanniana (G), W. indica (H), and W. rotundifolia (I). A. One population. B. General aspect showing greyish leaf indumentum. C. Detail of a flowering branch showing leaves and inflorescences arrangement. D. Stipule and inflorescence detail. E. Longistylous flowers showing the fan-plumose stigmas exserted. F. Brevistylous flowers showing stamens exserted. G. Detail of one inflorescence with a brevistylous flower. H. Inflorescence and detail of the homostylous flower. I. Inflorescence with brevistylous flowers.

Figure 3. Waltheria marielleae. A. Flowering branch with detail of the trichomes. B. Bracteoles. C. Brevistylous flower. D. Longistylous flower. E. Calyx showing internal surface. F. Calyx lobe with trichomes removed showing veins. G. Petal (adaxial surface). H. Stamens and part of the gynoecium of a longistylous flower. I. Stamens and stigma of a brevistylous flower. J. Gynoecium of a brevistylous flower. K. Capsule. L. Seed. A, B, D-H from Coutinho et al. 375 (UFP, holotype); C, I-L from Coutinho et al. 376 (UFP, paratype). Drawn by Regina Carvalho.

Figure 4. Geographic distribution map of Waltheria marielleae and new records of W. ackermanniana and W. rotundifolia. AL = Alagoas, PE = Pernambuco.