Adesmia sessilifolia Iganci & Miotto, 2011

Iganci, João R. V. & Miotto, Silvia T. S., 2011, Adesmia sessilifolia (Fabaceae), a new species from a relictual landscape in southern Brazil, Phytotaxa 26, pp. 21-24 : 22-23

Adesmia sessilifolia Iganci & Miotto , sp. nov. ( Figure 1 )

Ad Adesmia ser. Psoraleoides pertinens, A. paranensis Burkart similis, sed foliis sessili (non longi petiolata), foliola ovate-lanceolate (non oblongis), visibilibus venis ramosis (vs. mediana visibilibus sola) et 35 cm alta (vs. 70–90 cm alta) differt.

Type:— BRAZIL. Rio Grande do Sul: São Francisco de Assis , em campo, 16 January 1991, fl. and fr., Z . Machado 1236 (holotype ICN, isotype K) .

Small and ramose shrublets, up to 35 cm, perennial, with xylopodium, stems slightly lignified and branches glabrous except for brownish trichomes covering the inflorescences. Leaves paripinnate, sessile, 6–8 pairs of leaflets; leaflets ovate-lanceolate, 10–13 × 5–8 mm, apices obtuse and mucronate, both surfaces completely glabrous, chartaceous, glands absent, primary and secondary veines pronounced. Stipules lanceolate, 4 mm long. Racemes short, few-flowered, 4–9 cm long; bracts 5–6 mm long, triangular to lanceolate; pedicels 2–5 mm long, initially erect, curved after anthesis. Flowers yellow, 10–14 mm long; calyx 8–9 mm long, pubescent, campanulate, teeth 5, these 6–7 mm long; banner 9–11 × 10–14 mm, ovate to suborbicular, glabrous; wings 10–12 mm long, glabrous; keel 10–12 mm length, glabrous; stamens 10, filaments free; ovary 6–7 mm long, sessile, sericeous, style 8 mm, stigma punctiform. Fruit a hemicraspedia, dark brown, with 4–6 articles, subquadrangular, 4 × 4 mm. Seeds subdeltoid, 2 mm in diameter, with a developed dark brown aril.

Distribution: — Adesmia sessilifolia is only known from the central-western part of Rio Grande do Sul state, Brazil, in grasslands above outcrops of basalt close to sandy soils.

Etymology: —The epithet refers to the sessile leaves.

Additional specimens examined: — BRAZIL. Rio Grande do Sul: Santiago, litossolo sobre basalto, 23 March 1991, fr., J. F.M. Valls, Gomes, Moraes & Oliveira 12864 ( ICN, CEN); Quevedos, estrada Jarí- Quevedos , 9 December 2004, fl. and fr., S. Bordignon, R, Cancelli & R. Backes s.n. ( ICN) .

Discussion: — Adesmia sessilifolia is similar to A. paranensis Burkart (1954: 521) by having glabrous branches and leaves, pilose inflorescences and seeds with well-developed dark brown arils. It differs from that species in the size of the leaflets, by having sessile leaves with rounded leaflets with pronounced veines on both surfaces. Flowers and fruits appear later in the summer (December to March), compared with A. paranensis (October to December, rarely in February). In addition, A. sessilifolia differs in its geographic distribution, occurring in grassland on basaltic relicts in central-western Rio Grande do Sul, while A. paranensis is restricted to the core area of the fields on basalt, at higher elevations, between 840 and 1300 m, in the states of Santa Catarina and Paraná.

Figures

FIGURE 1. Adesmia sessilifolia. A. Branch. B. Flower. C. Calyx. D. Keel. E. Wing. F. Banner. G. Gynoecium. H. Pod. I. Seed. A–G from Z. Machado 1236 (ICN); H–I from Valls et al. 12864 (ICN, CEN). Drawn by J.R.V. Iganci.