Dorstenia acangatara M.D.M.Vianna, Al.Santos, A.F.P.Machado, Mansano & Romaniuc, 2013

Vianna, Marcelo D. M., Santos, Alessandra Dos, Machado, Anderson F. P., Mansano, Vidal De Freitas & Neto, Sergio Romaniuc, 2013, Dorstenia acangatara (Moraceae), a new and threatened species from Southeastern Brazil, Phytotaxa 118 (2), pp. 29-34 : 30-33

Dorstenia acangatara M.D.M.Vianna, Al.Santos, A.F.P.Machado, Mansano & Romaniuc , sp. nov., Fig. 1 ,

Fig. 2 .

Type: — BRAZIL. Minas Gerais: Caratinga, Estação Biológica de Caratinga, Fazenda Montes Claros , 19°44’11’’S / 41°49’18’’W, 578 m. s.m, 24 Mar 2000, J. A . Lombardi 3639 (holotype BHCB51149 !) .

Diagnosis:— Similis Dorstenia albertiio sed inflorescentis rubris et viridibus; margine inflorescentiae longe appendiculato-bracteata differt.

Description:— Herb to subshrub 30–50 cm tall; rhizome elongate, mainly supraterraneous; stem 4–5 mm thick, glabrous to sparsely puberulous, internodes up to 1–3 cm long. Leaves in spiral: lamina oblong-cordate 14–20 x 10–12 cm, chartaceous, apex acute, base cordate, margin entire to denticulate; adaxial side glabrous; abaxial side puberulous, lateral veins 6–7 pairs, tertiary venation reticulate; petiole 10–12 cm long, puberulous; stipules persistent, ovate to oblong acuminate, 5–8 mm long, plurinerveous, coriaceous, glabrous to puberulous. Coenanthium reddish; peduncle 4 cm long, diminutely puberulous; receptacle centrally attached, pateliform, 1–1,2 cm in diameter, outside dark green, minutely puberulous, internal side purplish, external side dark green, minutely puberulous; internal side purplish, glabrous to minutely puberulous, margin reddish, undulate; fringe to 0,4 mm long, long-appendiculate, appendages 9–17, 1 submarginal row, clavate, 0,5–1 cm long, reddish, puberulous short and long intercalate, usually with a green bract on its apex; staminate flowers among the pistillate flowers; tepals 2, stamens 2, puberulous, filament long; stigmas 2. Endocarp body not observed.

Distribution and Habitat: — Dorstenia acangatara is known only from two localities, from municipality of Caratinga, east Minas Gerais state and Alegre, south of Espírito Santo state, in Brazil, at elevations from 850 to 990 m in montane rainforest (collections marked by black dots in Fig. 3).

This species is a camephyte from shady and moist areas, which occur in litter soils, inside forests of the type locality. The new species is endemic to southeastern Brazil, found in the understory of wet tropical rainforest .

Etymology: —In the tupi language the epithet “acangatara” [acanga =head + tara =adornment] refers to the exuberant aspect of the coenanthium like a head adornment used by the Tupi’s, one of the main ethnic groups of Brazilian indigenous people.

MAP 1: Location of Dorstenia acangatara populations in Brazil (Minas Gerais and Espírito Santo states) .

Aditional speciments examined (paratypes): — BRAZIL. Espírito Santo: Alegre, between Monte Cristo and Burarama, Florestinha, 5 Out 2009, A . F .P. Machado et al. 855; 856; 858; 874 and 875 ( HUEFS, RB) .

Conservation Status: —According to IUCN (2011) criteria, this species is considered Critically Endangered (CR B1a) because its area of occupancy is less than 100 Km². The new species is known only from two localities.

Discussion: —This species falls into Carauta’s (1978) and Berg’s (2001) Dorstenia sect. Dorstenia L. species group. Dorstenia acangatara is characterized by the reddish coenanthium, with long appendages on its margin. The new species resembles D. albertii Carauta, Valente & Sucre (1974a:63) , which also occurs in the Atlantic forest. The two species shares oblong-cordate leaves and distance between the internodes, but can be promptly distinguished by inflorescence reddish with the margin appendiculate-bracteate. The new species also resembles Dorstenia fischeri Bureau (1873:211) by the stipules shape and distance between the internodes, but differs by nonpeltate leaves and appendiculate inflorescence margin (TABLE 1).

Figures

FIGURE 1: Dorstenia acangatara Photograph of the living plant in the field. (Julio Lombardi)

FIGURE 2: Dorstenia acangatara A: habit; B. Detail of the stipules (scale: 5 mm); C. detail of coenanthium (scale: 1 cm).