Strychnos nana E.Brandão, 2017

Brandão, Ellen Kallyne De Sousa & Rapini, Alessandro, 2017, Novelties in Strychnos sect. Breviflorae (Loganiaceae), Phytotaxa 329 (3), pp. 262-268 : 263

Strychnos nana E.Brandão , sp. nov. ( Figs 1A–I and 2 ).

Type:— BRAZIL. Tocantins, Ponte Alta de Tocantins, 10°45’36”S, 47°31’12”W, 336 m, 19 November 2008 (fl., fr.), C. W. Fagg. 3671 (holotype HUEFS!, isotypes IBGE!, RB!).

Strychnos nana is morphologically similar to S. parvifolia A.DC. and S. rubiginosa A.DC. but can be distinguished from them by highness (0.2–0.4 vs. 0.7–4 m), length of leaf blade (0.7–1.1 vs. 2–8.5 cm), peduncle (absent or up to 0.6 cm vs. 0.5–3 cm long), number of flowers per thyrse (9–12 vs. 15 or more), shape of bracts (ovate vs lanceolate to oblanceolate) and length of calyx lobes (0.8–1 mm vs. 1–1.5 mm).

Herbs erect to prostrate shrubs, 0.2–0.4 m high; branches light brown, cylindrical, densely pubescent, spines and tendrils absent; stipules linear. Leaves opposite; petiole up to 1 mm long or absent, scabrous to puberulous; blade green to reddish brown, discolour, 0.7–1.1 × 0.3–1.1 cm, ovate to deeply ovate, subcordate to cordate at base, rounded at apex, usually thickened and ciliated along margins, often only distally, coriaceous to subcoriaceous, glabrous on both sides, 5-plinerved. Thyrses 9–12-flora, congested, terminal; peduncle absent or up to 6 mm long, puberulous; bracts 1–2(–2.5) mm long, ovate, acute at apex, ciliated; bracteoles 0.5–1 mm long, ovate, acute at apex, ciliated. Flowers 4-merous in the lateral cymes and 5-merous in the terminal cymes, sessile or pedicel up to 1 mm long, puberulous; calyx 4- or 5-merous, green, lobes 0.8–1 × 0.8–1 mm, ovate, acute at apex, hyaline cilia along the margins; corolla 4- or 5-merous, white, cream to light green, short-infundibuliform, tube 0.6–0.8 mm, lobes 2.8–3 × 0.8–1.3 mm, ovate to narrowly ovate, abaxially papillose, adaxially bearded; stamens 4 or 5, filaments cream, 0.2–0.3 mm long, pilose, anthers yellow, 0.7–0.8 mm long, oblong-obcordate, pilose at base; ovary 0.6–0.7 mm long, style 0.5–0.7 mm long, stigma capitate. Berries green when immature, 0.5–0.8 × 0.6–0.8 cm, pericarp succulent, rugose, glabrous; seeds not seen.

Additional specimens examined (paratypes): — BRAZIL. Bahia, Correntina, 5 km from Correntina, 13°25’20”S, 44°40’44”W, 31 October 2009 (fl.), J. G. Freitas 559 ( HUEFS). Tocantins, Ponte Alta de Tocantins, 10°26’39”S, 47°09’27”W, 334 m, 8 November 2009 (fl.), E. Melo 7150 ( HUEFS).

Etymology: —The epithet nana refers to the small size of the individuals of this species when compared to the other American species of Strychnos .

Distribution and habitat: — Strychnos nana occurs in savannas of the Cerrado domain, states of Bahia and Tocantins, on sandy to clayey soils.

Phenology: —The new species has been found with flowers from October to November and fruits in November.

Notes: — Strychnos nana is similar to S. parvifolia Candolle (1845: 16) and S. rubiginosa Candolle (1845: 16) . The three species belong to Strychnos sect. Breviflorae , occur sympatrically in the Cerrado domain and are found in savannas. They share reproductive features, such as the short-infundibuliform corolla, fruits with succulent pericarps, with only 1 or 2 seeds per fruit. However, the new species can be easily recognised by the small habit (<50 cm high), reduced leaves (≤ 1 cm long), thickened along the margins, and the congested cymes ( Fig. 1D ), with 4-merous flowers in the lateral branches ( Fig. 1F ) and 5-merous in the apical ones ( Fig. 1G ). Tab. 1 shows the main features to distinguish the three species.

Figures

FIGURE 1.A–I. Strychnos nana: A. branch with buds and flowers; B. leaf, adaxial side; C. leaf, abaxial side; D. inflorescence with buds and flowers; E. bract, abaxial side; F.flower (4-merous form); G. calyx (5-merous form), open to show abaxial side and margins; H. pistil, showing the capitate stigma; I. stamen. J–K. S. alvimiana: J. berry, half in cross section to show the sub-woody pericarp and seed; K. seed, ventral view. L–N. S. atlantica: L. branch with terminal inflorescence; M. Dicasium of a thyrse; N. corolla, open to show the indument of the adaxial side of corolla and the stamens. (A–I from C.W. Fagg. 3671 in HUEFS; J–K from T.S. Santos 2683 in CEPEC; L–N. from R.S. Pinheiro 2281 in CEPEC).

FIGURE 2. Distribution map of Strychnos nana in Brazil (top right), with the states of Tocantins (left) and Bahia (right) darker.