Aristolochia subglobosa J. Freitas, Lírio & F. González, 2013

Freitas, Joelcio, Lírio, Elton John De & González, Favio, 2013, A new cauliflorous species of Aristolochia (Aristolochiaceae) from Espírito Santo, Brazil, Phytotaxa 124 (1), pp. 55-59 : 56

Aristolochia subglobosa J. Freitas, Lírio & F. González , sp. nov. ( Figs. 1 , 2 )

The new species is similar to A. bahiensis , A. daemoninoxia and A. guentheri , from which it differs by the following set of characters: Non-peltate leaf blade; massive, inequilateral syrinx; broadly elliptic to broadly obovate and almost flat floral limb with rounded base slightly undulate margin and obtuse apex obtuse; and short (≤ 1.9 cm long) and nearly globose capsule ( Table 1).

Type:— BRAZIL, Espírito Santo: Município de Vila Valério, ES 358, distrito de Araribóia, em borda de fragmento [Espírito Santo state: municipality of Vila Valerio, ES 358 highway, district of Arariboia , in margin of forest fragment], 100–200 m, 19º02’51’’S, 40º16’48’’W, 01 September 2012 (flower, fruit), J . Freitas & A . M . Assis 180 (Holotype: MBML!; isotype: COL!) .

Glabrous vines. Old stems corky. Twigs cylindrical, internodes to 7.5 cm long. Leaves glabrous; petiole 3.6– 7.2 cm long, the proximal half thicker; lamina ovate-deltoid, 9-23 × 4.1–10.8 cm, base truncate to slightly cordate (with a sinus to 1.1 cm deep), not peltate, apex acute to acuminate, chartaceous, basal primary veins 3(5). Pseudostipules absent. Flowers arranged in short, cauliflorous racemes, 7–10 mm long each, with internodes <1 mm long, up to 11 flowers per raceme, subtending bracts deltoid, 2–2.5 × 1.8–2 mm, pubescent at their margins. Peduncle plus ovary 0.8–1.5 cm long. Perianth slightly curved before anthesis, then the curvature between the utricle and the tube becomes more pronounced, glabrous and beige with thick vinaceous grooves on the outside, with whitish, thick hairs on the inside, the lower 1/3 vinaceous, the rest whitish-yellow, lower 2/3 pilose, the rest glabrous on the inside; utricle ovoid, 4-6 × 5–6 mm, syrinx 1.5–1.8 mm long, inaequilateral, tube funnel-shape, 0.8–1.5 cm long, 2.0– 2.2 mm proximal diameter, 7–14 mm distal diameter, limb broadly elliptic to broadly obovate, 2.2–2.9 × 1.3–1.7 cm, with the upper half almost flat, margin vinaceous, slightly undulate, base emarginate, not peltate, apex obtuse but ending in a very short acumen. Gynostemium shortly stipitate, 2–3 mm long; anthers oblong, to 0.9 mm long. Capsule subglobose, c. 1.9 × 1.6 cm, midvein of each carpel prominent, ca. 3 mm thick, septa entire, apex shortly rostrate; seeds unknown.

Distribution and habitat: — Known only from northern Espírito Santo, Brazil, in the municipality of Vila Valério, at 100–200 m in wet tropical Tertiary Tableland Forest.

Phenology: — This species has been collected with flowers and fruits in September. Only a single capsule (with seeds already dispersed) was found during the collection of the type specimen.

Conservation status: — Tentatively, the species may be considered Critically Endangered (B1, B2a, B2b(iii), and D) according to the IUCN Red List ( IUCN, 2011), due to the very small extent of occurrence (<100 km ²), with just a place of occurrence and a single populations; small area of occupancy (<10 km ²); fragmentation and decline in the quality of habitat and few mature individuals known (<50).

Etymology: — The specific epithet refers to the nearly globose capsules, a condition that is very uncommon in the species of subser. Anthocaulicae , in which long, cylindrical capsules are typical (cf. Table 1).

Comments: — Aristolochia subglobosa resembles A. daemoninoxia , from Guyana, A. guentheri , from the western Amazonian basin, and A. bahiensis , from the southern Atlantic Forest of Brazil (cf. Schmidt, 1930; González, 1990, 1994, 1998; Feuillet & Poncy, 1998). The new species differs by the presence of an inequilateral syrinx (absent in the other species), and by the peculiar shape and size of the perianth limb and the capsule ( Table 1). All these characters are diagnostic not only for the Colombian, Ecuadorian, Brazilian and Guyanian species of the subseries Anthocaulicae ( González, 1990, 1994, 1998; Feuillet & Poncy, 1998) but also for the remaining species of this subseries from Central America (e.g. A. cruenta Barringer [1983: 171] , A. schippii Standley [1930: 8] ), Venezuela (e.g. A. disticha M. T. Masters [1875: 110] ), Peru (e.g. A. cauliflora Ule [1905: 120] , A. iquitensis O. C. Schmidt [1927: 196] , A. lagesiana Ule [1905: 119] ), and Bolivia (e.g. A. guentheri ) (González, unpublished data).

Figures

FIGURE 1: Aristolochia subglobosa. A Twig. B Old stem with a cauliflorous raceme. C-D Flower in lateral view with details of the apex of the limb (D). E Slightly undulate margin of the floral limb. F Dissected utricle showing the massive, inequilateral syrinx on top of the gynostemium. G Raceme with six small bracts. H Bract. I Dehisced capsule. J-K Individual carpel after capsule dehiscence, in lateral (J) and distal (K) views. Drawn from the type collection, by J. Freitas.

FIGURE 2: A Young raceme with flowers before anthesis, side view. B Raceme with flowers before anthesis (on the back) and a flower during anthesis in frontal view. Arrows point at bracts. Photographs by J. Freitas.