Aristolochia assisii J. Freitas, Lírio & F. González, sp. nov. (Figs. 1, 3)

Aristolochia assisii resembles A. bahiensis, A. disticha, and A. subglobosa but differs by the herbaceous habit, the membranous and very widely ovate leaves, the shortened elliptic limb of the perianth, the massive syrinx, and the small, fusiform and long-rostrate capsule. The herbaceous habit of the new species resembles that of Aristolochia holostylis (formerly Holostylis reniformis), from north, northeast and central Brazil and adjacent Paraguay, but clearly differs by the possession of cylindrical xylopodia, inflorescences with small bracts and extremely short internodes, perianth clearly differentiated in utricle, tube and an oblique limb, and small but long-rostrate capsules (Fig. 3D). A. holostylis possesses fascicled, homogeneous roots (the primary root not evident), inflorescences with elongated internodes and expanded or slightly reduced subtending leaves, a bell-shaped perianth not clearly differentiated in utricle, tube and limb, and narrowly cylindrical, not rostrate capsules (Table 1).

Type:— BRAZIL, Espírito Santo: Município da Serra, Mestre Álvaro - vertente sudeste. Próximo a FURNAS. Acesso pelo Bairro Jardim Tropical. [Espírito Santo state: municipality of Serra, Mestre Alvaro – southeast slope, near FURNAS. Access by neighborhood Jardim Tropical], 200 m, 20º10’50,5’’S, 40º18’25,4’’W, 20 April 2013 (flower), R. Santos 80 (holotype MBML!; isotype COL!).

Herbs to 32 cm tall, old stems not corky. Xylopodium subcylindrical and tortuous, corky, branched or unbranched, 38.2–63 cm long and 1.7–2.9 cm in diameter. Twigs cylindrical, striate, internodes up to 9,1 cm long. Leaves petiolate; petiole 5,6– 16.5 cm long; blade very widely ovate, 13.8–16.5 × 11.0– 17.5 cm, membranaceous, glabrous above, puberulous below, base deeply cordate with a sinus 2,8– 4.4 cm deep, not peltate, apex acuminate, basal primary veins 7. Pseudostipules absent. Flowers arranged in short axillary racemes, 4–30 mm long and with 6–23 flowers each, the internodes <1 mm long, the subtending bracts narrowly-ovate, to 4.1 × 2.9 mm, shortly petiolate, glabrous. Peduncle plus ovary up to 1.15–1.45 cm long. Outer surface of the perianth glabrous and beige with small vinaceous spots, inner surface vinaceous in the proximal 1/6, the rest whitish-yellow and with vinaceous trichomes; utricle ovoid, up to 1.1 × 0.7 cm, syrinx up to 1.5 mm long, inaequilateral; tube funnel-shape, about 1.66 cm long, proximal diameter 0.27 cm, and distal diameter 0.77 cm; limb broadly elliptic, 1.82–2.0 × 1.1–1.3 cm, slightly concave proximally, base emarginate, not peltate, margins revolute, apex obtuse, emarginate. Gynostemium stipitate (stipe 1–1.2 mm), 2.6–3 mm long; anthers oblong, up to 1.5 mm long. Capsule fusiform, up to 3.2 × 1.15 cm, hexagonal in transverse section, acropetally dehiscent, the distal portion transformed in a long, tapered rostrum to 1.2 cm long, with a subapical protuberance, septa entire. Seeds ovoid, to 4.1 × 3.3 mm, concave-convex, warty, non-winged, with a massive cylindrical raphe.

Additional specimens examined (Paratypes):— BRAZIL, Espírito Santo: Município da Serra, Mestre Álvaro - vertente sudeste. Próximo a FURNAS. Acesso pelo Bairro Jardim Tropical. [Espírito Santo state: municipality of Serra, Mestre Alvaro – southeast slope, near FURNAS. Access by neighborhood Jardim Tropical], 200 m, 20º10’50,5’’S, 40º18’25,4’’W, 23 March 2010 (flower), A. M. Assis et al. 2327 (MBML); 07 August 2010 (flower), A. M. Assis et al. 2597 (MBML). Espírito Santo: Município de Guarapari, distrito de Setiba, mata seca de Restinga (Floresta não-inundável) [Espírito Santo state: municipality of Guarapari, district of Setiba, dry forest of Restinga (Non-Flooded Transitional Forest)], 10 July 1991 (fruit), L. V. da Rosa et al. 166 (VIES); 17 August 1991 (flower), L. V. da Rosa et al. 204 (VIES). Bahia: Município de Itamarajú, Alto Pau Brasil, Monte Pescoço, Fazenda Novo Horizonte, Propriedade do Sr. Carlinhos Mascarenhas. Cabruca. [Bahia state: municipality of Itamaraju, locality of Alto Pau Brasil, Monte Pescoço, Novo Horizonte farm, property of Mr. Carlinhos Mascarenhas] 188 m, 16º59’20’’S, 39º34’36’’W, 20 April 2009 (flower), A. P. Fontana et al. 5884 (MBML).

Distribution and habitat: — Aristolochia assisii occurs in wet tropical areas, in transition of Atlantic Rain and Tertiary Tableland forests in the state of Bahia, and in Atlantic Rain and Restinga forests in the state of Espírito Santo (Fig. 2).

Phenology: — The Espírito Santo populations set flowers in March and August, and fruits in July; the population at the Mestre Alvaro locality has not set fruits during three years field study in the area by André Assis (pers. comm.). The Bahia populations set flowers in April.

Conservation status: — Tentatively, the species may be considered Endangered (B1, B2a, B2b(iii), and D) according to the IUCN Red List (IUCN, 2011) and the Geospatial Conservation Assessment Tool (GeoCat) (Bachman et al., 2011), due to the small area of occurrence (<5,000 km ²), small area of occupancy (<500 km ²), with just 3 places of occurrence and 3 populations; fragmentation and decline in the quality of habitat and few mature individuals known (<50).

Etymology: — The specific epithet honors the Brazilian botanist André Moreira de Assis, mentor of many biologist in the country and one of the collectors of the new species.

Comments: — The floral morphology of Aristolochia assisii resembles that found in A. disticha Mast., from Venezuela (Alto Orinoco), Brazil (Amazonas and Pará), French Guiana (Saint Laurent), and Peru (Brako & Zarucchi 1993; Feuillet & Poncy, 1998; Funk et al., 2007; Barros & Araújo, 2014), and in A. bahiensis and A. subglobosa (the latter two sympatric with the new species). However, A. assisii possesses a unique herbaceous habit and a relatively rapid flowering, which might indicate the occurrence of neoteny in this species. All the remaining species of subseries Anthocaulicae are woody climbers and the flowering occurs after many years of vegetative growth. The presence of racemose inflorescences in a herbaceous Aristolochia occurs in A. holostylis (González, 2012), but in this species the internodes of the raceme are not shortened and the subtending leaves are not as reduced as in A. assisii. In Table I we compare in detail the habit as well as the morphology and size of the perianth and the capsule of these five species.

In the new species, the young perianth is almost linear in relation to the utricle (Figure 3 B (a)), but the curvature between the utricle and the tube gradually reaches an angle of 60º by the time of anthesis (Figure 3-B (b)). By post-anthesis, the limb curves inwards (Figure 3-C). Gradual changes often occur during perianth development and growth. The variation observed in the contour of the perianth during flower development and growth is observed also in many species of Aristolochia (Costa & Hime, 1981; González & Stevenson 2000, Freitas et al. 2013B).