Bernardia fluviatilis J.F. Carrión, 2024

Carrión, Juan F. & Amorim, André M., 2024, A new species of Bernardia (Euphorbiaceae, Acalyphoideae) with stellate trichomes from South America, Phytotaxa 650 (1), pp. 1-7 : 2-6

Bernardia fluviatilis J.F. Carrión , sp. nov. ( Figs. 1–2 )

Type: — BRAZIL. Mato Grosso do Sul: Corumbá, Porto Amolar , atrás da base da Ecoa . 18º2’24”S, 57º29’28”W, 120 m elev., 24 November 2018 (♂ fl., ♀ fl., and fr.), Carrión & Antunes 1875 (holotype: HUEFS!, isotypes will be sent to the following herbaria: CEPEC, CGMS, COR, K, MO, NY, PMA, RB, US).

Diagnosis:— Bernardia fluviatilis is similar to B. argentinensis Lourteig & O’Donell (in Lourteig 1955: 75) because it is usually monoecious and has a membranaceous leaf blade with stellate trichomes, staminate inflorescences racemiform and elongated, and staminate flowers conspicuously pedicellate, but differs by its young branches covered by a sparsely (vs. densely) sericeous indumentum of simple trichomes (vs. simple and/or stellate trichomes), staminate peduncles 3–6 (vs. 5–25) mm long, cymules scattered (vs. congested to scattered) along the axis of the staminate inflorescences, and staminate flower pedicel usually glabrous (vs. covered by simple and/or stellate trichomes).

Description:— Usually monoecious shrubs, 0.4–2 m tall, with indumentum of simple and stellate trichomes. Stem and old branches glabrous, lenticellate; branches striate, cylindrical, young branches covered by sparsely sericeous indumentum of simple trichomes. Stipules 0.9–1.5 × 0.2–0.4 mm, lanceolate, attenuate, rigid, thickened, covered by appressed, simple trichomes, persistent after the leaf falls. Leaves alternate; blade membranaceous, ovate to elliptic, 3–11 × 1–5 cm; discolorous; base cuneate; margin serrate, with glandular teeth, basally entire; a conspicuous pair of circular basilaminar glands present, these sometimes reddish, and 3–7 inconspicuous circular glands present around the blade; apex attenuate to acute, sometimes obtuse; abaxial surface pubescent, trichomes stellate, with 3–11 arms, simple trichomes present on the veins and margin, adaxial surface puberulent, trichomes stellate, with 2–9 arms, smaller than those on abaxial surface; venation palmati-pinnate, secondary veins in 5–9 pairs, intersecondary veins percurrent, usually depressed; petiole 2–6 mm long, covered by appressed, simple trichomes. Staminate inflorescences axillary, spiciform, 0.6–2.9 cm long at anthesis, pedunculate, peduncle 3–6 mm long, erect, covered with appressed, simple trichomes, bracts (1–)2–10, scattered along the axis, concave, ovate, apex acuminate, 1–1.7 × 1.1–1.5 mm, pale yellow, thickened, ciliate, outer surface covered with sparse, appressed, simple trichomes, inner surface glabrous; each bract subtending cymules of 3–8 flowers; surrounded by many linear bracteoles, these 0.5–1 mm long, pubescent. Staminate flowers pedicellate, pedicel articulate, conspicuously exserted to the bract at anthesis, 2–4.2 mm long at anthesis, glabrous to glabrescent; sepals 3(–4), valvate, ovate, 0.8–1.1 × 0.5–0.8 mm, hyphodromous, outer surface with sparse, simple trichomes, these denser at the apex and base, inner surface glabrous; stamens 7–10; filaments 0.3–0.7 mm long, alternating with shortly stalked segments of dissected disc; anthers 0.1–0.2 × 0.1–0.2 mm, basifixed, 4-locellate, dehiscent through longitudinal slits, connective emarginate. Pistillate inflorescence terminal, a sessile or shortly glomeruliform cyme, a pedunculate short, spiciform inflorescence, or an individual flower. Pistillate flowers sessile; each one subtended by 3 bracts, these ovate to lanceolate, ciliate, concave, unequal in size and shape, 1.2–1.9 × 0.7–1.4 mm, one bract conspicuously broader that the other two bracts, with an acute to attenuate apex, covered by appressed simple trichomes on the outer surface, glabrous on the inner surface, sometimes thickened on the basal sides, appearing glandulate; sepals 4–5, ovate, persistent, 0.8–1.8 × 0.5–1.4 mm, conspicuously ciliate, hyphodromous, outer surface with sparse, simple, appressed trichomes, inner surface glabrous; ovary globose, sericeous, styles 3(–4), bipartite, recurved, 0.4–0.8 mm long, branches to 0.5 mm, entire, stigmatic surface smooth, glabrous or sometimes with sparse, adpressed simple trichomes. Fruits globose, trilobed, 4.5–7 × 5–9 mm, verrucose, green when mature, sparsely sericeous, with persistent styles, bracts, and calyx; sometimes pedicellate, pedicel to 5 mm long; mericarps 2-valved, splitting septicidally then loculicidally; columella 2.5–4 mm long, trilobed, persistent. Seeds carinate, 3–5 (long) × 2–4 (deep) × 2.5–3.5 (wide) mm, with sinuate carina, cordiform in ventral view, verrucose to smooth, shiny, buff, sometimes marbled brown.

Additional specimens examined (paratypes):— BOLIVIA. Santa Cruz: Germán Busch, Puerto Quijarro, Puerto Isabel , Laguna Mandiore , 18°11’49.1”S, 57°30’37.8”W, 23 November 2010 (♂ fl., ♀ fl., and fr.), Yule et al. 81 ( CGMS) . BRAZIL. Mato Grosso: Poconé, Morro do Caracará ( Ilha Fluvial ), Parque Nacional do Pantanal , 100 m elev., 17°51’2”S, 57°26’53”W, 4 May 2001 (♂ fl., ♀ fl., and fr.), Damasceno Junior et al. 2290 ( COR, SP) ; Mato Grosso do Sul: “ Cerro Pedrera, circa Cerro Morriño, sed trans Riacho Navileque , 50–60 km N. Fuerte Olimpo , Alto Paraguay ”, 30 March 1980 (♀ fl. and fr.), Bernardi 20410 ( MO, NY, US) ; Corumbá, a 200 m da divisa com Bolivia, estrada do Jacadigo , 12 July 1972 (♂ fl., ♀ fl., and fr.), Almeida de Jesus 1706 ( RB) ; ibid., Sub-região Pantanal do Paraguai, Morro do Amolar , 645 m elev., 18°1’09.2”S, 57°32’3.8”W, 25 November 2010 (♂ fl., ♀ fl., and fr.), Stefanello et al. 258 ( CGMS) ; ibid., Baía do Taquaral , 88 m elev., 18°2’28.2”S, 57°29’26.2”W, 26 November 2010 (♂ fl., ♀ fl., and fr.), Stefanello et al. 263 ( CGMS) ; ibid., Região da Serra do Amolar , próximo à ECOA, 18°02’28.2”S, 57°29’26.1”W, 26 November 2010 (♂ fl., ♀ fl., and fr.), Neves et al. 68 ( CGMS) ; ibid., Porto Amolar , atrás da base da Ecoa, 18º2’24”S, 57º29’28”W, 120 m elev., 24 November 2018 (♂ fl.), Carrión & Antunes 1877 ( HUEFS) ; ibid., (♂ fl., ♀ fl., and fr.), Carrión & Antunes 1879 ( HUEFS) . PARAGUAY. Alto Paraguay: (as “ Chaco Paraguayo ”), Puerto Casado, Obraje Mosquito , December 1916 (♂ fl., ♀ fl., and fr.), Rojas 2169 ( A, SI) .

Distribution:— Bernardia fluviatilis occurs in the Pantanal wetland, in border areas of Bolivia (Puerto Quijarro, Santa Cruz), Brazil (Poconé, Mato Grosso and Corumbá, Mato Grosso do Sul), and Paraguay (Puerto Casado, Alto Paraguay), which partially coincides with the riverbed of the Paraguay River and its tributaries (fig. 3).

Etymology:— The specific epithet refers to the riparian habitat of this species.

Conservation assessment:— Bernardia fluviatilis is known from seven localities, of which most are difficult to access and only one is in a protected area (Pantanal Matogrossense National Park, municipality of Poconé, Mato Grosso State). The extent of occurrence (EOO) of B. fluviatilis was estimated to be 6,883.8 km ², which qualifies it for the Vulnerable (VU) category, and the area of occupancy (AOO; grid cell area of 2 km ²) was calculated to be 28 km ², which qualifies it for the Endangered (EN) category. Thus, following the IUCN Red List categories and criteria ( IUCN 2022), we believe that if a formal assessment was conducted B. fluviatilis would probably be classified as vulnerable [VU B1 a, b (i, ii)].

Habitat, ecology, and phenology:— This new species grows in areas of seasonally dry forest, rocky outcrops, savannas (cerrados), forest savanna (cerradão), riverine forests, open disturbed areas, and transitional flooded zones associated with the riverbed of the Paraguay River and its tributaries in the Pantanal wetland.This distribution associated with a watercourse might be related to hydrochorous dispersal. Bernardia fluviatilis seems to be a pioneer species, since it has been documented growing in anthropized areas, as observed in the type locality where many individuals (ca. 50) of this species were found. It has been recorded with flowers and fruits in March, May, July, November, and December.

Taxonomic comments:— Bernardia fluviatilis resembles Bernardia argentinensis and B. paraguariensis by its stellate trichomes and spiciform, elongated, pedunculate staminate inflorescence, with flowers that are conspicuously pedicellate and have bifid styles. These three species belong to the same lineage ( Carrión 2020). Bernardia fluviatilis is sympatric with Bernardia paraguariensis and both have a staminate inflorescence with cymules scattered along the inflorescence axis, but B. fluviatilis can be differentiated by its usual monoecy (vs. dioecy), young branches covered with a sericeous (vs. velutine-tomentose) indumentum of simple (vs. stellate and simple) trichomes, membranaceous (vs. chartaceous) leaf blade with tertiary veins usually depressed (vs. prominent), and axis of the staminate inflorescence covered by a sericeous (vs. densely tomentose) indumentum of simple (vs. stellate and simple) trichomes. Bernardia fluviatilis can be differentiated from B. argentinensis by the characteristics mentioned in the diagnosis, and B. argentinensis is endemic to northwestern Argentina and the Boqueron Department in Paraguay, while B. fluviatilis occurs in border areas of Bolivia, Brazil, and Paraguay (Alto Paraguay Department) and follows the riverbed of the Paraguay River.

Additionally, we considered the possibility that the new species could belong to one of the varieties ( Chodat & Hassler 1905) or forms (Pax & Hoffman 1914) described for Bernardia paraguariensis . Particularly, we considered B. paraguariensis var. fruticosa Chodat & Hassler (1905: 504) because it was described from a specimen collected on a riverbank, a similar habitat of the new species, but detailed observations of the type specimen of B. paraguariensis var. fruticosa demonstrated that it is conspecific with B. paraguariensis .

The label of the Bernardi 20410 specimen says the collection was made in Paraguayan territory: “Cerro Pedrera, circa Cerro Morriño, sed trans Riacho Navileque, 50–60 km N. Fuerte Olimpo, Alto Paraguay.” However, “Cerro Pedrera” maybe = “Morro da Pedreira” that is in the municipality of Corumbá and “Riacho Navileque” maybe = “Rio Nabileque” that is located on the border of the municipalities of Corumbá and Porto Murtinho, which are both completely within Mato Grosso do Sul State. Thus, this collection is probably from Brazil near the border of Paraguay. This possible mistake was also noted by Oliveira et al. (2013).

Figures

FIGURE 1. Bernardia fluviatilis. A, fertile branch; B, detail of young branch showing indumentum; C, detail of abaxial leaf surface with basilaminar glands; D, detail of adaxial leaf surface with indumentum; E, detail of abaxial leaf surface with indumentum; F, detail of leaf margin with glandular teeth; G, fruits and staminate inflorescence; H, staminate cymule and flower at anthesis; I, staminate bract in ventral view; J, staminate bracteoles; K, pistillate flower; L, gynoecium; M, pistillate bract; N, pistillate sepal; O, seeds, from left to right in ventral, dorsal and lateral view. Drawings by Klei Sousa, based on Carrión & Antunes 1875.

FIGURE 2. Bernardia fluviatilis: A, habit; B, fertile branches with detail of leaf blade margin; C, staminate inflorescence with detail of flower; D, fruits. Photographs by J.F. Carrión.