16. Adesmia riograndensis Miotto, Bradea 6(29): 249–250, Fig. 1, (1993).

Type:— BRAZIL. Rio Grande do Sul: Bagé, 2.2 km do Rio Camaquã, em direção à Bagé, ao longo da rodovia BR-153, 17 October 1988, {fl./fr.}, Valls, J. F. M. et al 11931 (holotype: CEN barcode CEN00013658 [photo!], isotypes: ICN barcode ICN00000352 [photo!]; K barcode K000222470!; NY barcode NY00004966 [photo!]; SI barcode 004015 [photo!]; UEC barcode UEC00056025!) .

Ascendant to erect subshrubs, adventitious roots from stem branch nodes absent. Stem pilose, abundant ochraceous glandular setules on all plant parts. Stipules 5–10.8× 1.2–3.2 mm, deltate to lanceolate, pilose to glabrous. Leaves with (4–)5–7(–8) pairs of leaflets; petiole 0.5–0.8 cm long, rachis 0.9–3.7 cm long, pilose; leaflets 1.8–6.8× 1.2–8.1 mm, elliptic to obdeltoid, apex retuse, base acute to rounded, margin entire, glabrescent to glabrous. Racemes or panicles, terminal, 9.5–29 cm long, pilose; bracts 3.1–6.4 mm long, lanceolate to linear, pilose to glabrous; pedicel 3.6–34.1 mm long, pilose. Flowers 7–9.2 mm long; calyx 2.6–4.6 mm long, externally pilose, internally hirsute with white tector hairs; lobes 1.5–2.2 mm long, linear to triangular; standard petal straight, 7.3–9.2× 5.1–7.8 mm, orbicular, apex obtuse, externallY glabrous, claw 1.9–2.7× 0.6–0.9 mm, internallY pubescent distallY; wing petals 5.5–8.3× 2.3–3.3 mm, falcate to oboVate, claw 2.1–3 mm long; keel petals 5.2–6.5× 2.3–2.75 mm, falcate, claw 1.9–3 mm long; stamens 6.3–8.1 mm long, anthers orbicular; gynoecium 7.2–9.1 mm long, ovary 3.5–5 mm long, hirsute, 2–5-ovulate. Lomentum 5–21 mm long, straight, dark brownish to black, pilose and muricate, stiff ochraceous setules at the centre of each article, fruit with (1–)2–4(–6) articles, these 2.4–4.9× 3.2–4.4 mm, orbicular to slightlY triangular. Seeds brownish to black, 1.7–2.4× 1.3–2.6 mm, reniform, without an aril. (Figures 20 G–I, 28).

Distribution and Habitat— The species is endemic to Rio Grande do Sul, and is currently known from three areas: Minas do Camaquã (Guaritas) near Caçapava do Sul; at 2.2 km from Rio Camaquã at Bagé, and at Cerro do Diogo in Santana da Boa Vista (Fig. 27). The species inhabits shrubby vegetation that dominates this region of the Pampas (Fig. 6).

Phenology— The species flowers from September to October, and fruits from October to November.

Conservation status— Critically Endangered (CR) B2ab(iii). Adesmia riograndensis has an extremely restricted distribution, with an EOO of 428,369 km ² and AOO of only 20 km ². The species is known only from Minas do Camaquã, in the south of Rio Grande do Sul state, Brazil, and closely surrounding areas. These areas face pressures from mining and agriculture, resulting in the potential future habitat loss of Adesmia riograndensis .

Etymology— The specific epithet alludes to the Brazilian state of Rio Grande do Sul, where the species was first collected and to which it is apparently endemic.

Notes— Adesmia riograndensis is morphologically similar to A. securigerifolia Herter due to their shared retuse leaflets and lomentaceous fruits with few articles (Fig. 28). Notwithstanding, the species is easily distinguished by its racemose or paniculate inflorescence and leaves with 4–8 pairs of leaflets (vs. axillary solitary flowers and leaves with 3–5 pairs of leaflets in A. securigerifolia).

Additional Specimens Examined — BRAZIL. RIO GRANDE DO SUL: Bagé, 2, 2 km do Rio Camaquã em direção a Bagé, BR-153, 06 November 1987, Valls, J. F. M. 11930 (UEC 62362). Caçapava do Sul, Guaritas, 25 April 1985, Brack, P. & Stehmann, J. R. s/n (paratype ICN 00000271 [photo!]); 01 November 1991, Jarenkow, J. A. & Garcia, E. N. 3613 (MBM 227183; ESA 060450 [photo!]; CRI 002568 [photo!]); 12 November 1991, Schlindwein, C. 1216 (MPUC 13624). Serra do Seival, 01 November 1990, Machado, L. A. Z. 634 (SMDB 3735). Santana da Boa Vista, Cerro do Diogo, September 1985, Sobral, M. et al. 4261 (paratype ICN 00000272 [photo!]; LUSC 000279 [photo!]) .