Adesmia subtropicalis Cobra, 2021

Cobra, Thiago, Iganci, João Ricardo Vieira, Miotto, Silvia T. S. & Fortuna-Perez, Ana Paula, 2021, Adesmia subtropicalis (Leguminosae, Papilionoideae, Dalbergieae), a new endangered species from the Brazilian Pampas, Phytotaxa 521 (3), pp. 219-226 : 220-224

Adesmia subtropicalis Cobra , sp. nov.

TYPE:— BRAZIL. Rio Grande do Sul: Soledade, Road RS-332 from Soledade to Espumoso , 3 nov. 2019 (fl.), Monteiro, T. C., Silva, I. C. C., Gissi, D. S., Bezerra, L. M. P. A. & Fortuna-Perez, A. P. 223 (holotype, BOTU ; isotypes, ICN; HAS; PEL; MBM; RB; UEC)

Diagnosis—Hirsute indumentum with long golden glandular hairs up to 3 mm long; Inflorescence densiflorous, sometimes with flowers limited to the apex of the raceme; bracts 6–13 mm long, flowers 10–15 mm long, calyx lobes 5–9 mm long; fruit black, seeds short - arilated. Similar to A. punctata var. punctata ( Poiret 1804:447) De Candolle (1825:95) , which have a laxer inflorescence never limited to the apex of the raceme, shorter bracts (3–5 mm long), flowers (8–10 mm long), calyx lobes (3–6 mm long); brownish fruit and seeds with no aril.

Prostrate to ascendant herb with adventitious roots from branch nodes, hirsute, with white short tector trichomes (up to 0.3 mm long) and golden long glandular hairs, sometimes with a reddish base (up to 3 mm long) on all green plant parts; stipules 5–10 × 1–3 mm, triangular to narrowly-triangular, pubescent to pilose. Leaf paripinnate, rarely pseudoimparipinnate (with an aborted leaflet at the last pair of leaflets), with (7–) 8–10 (–12) pairs of leaflets; petiole 5–25 mm long, rachis 7–50 mm long, pubescent to pilose; leaflet 4–14 × 1.5–4 mm, elliptic to oblong, apex obtuse to mucronate, base acute to rounded, uninervous venation, glabrous to pubescent. Inflorescence racemose to paniculate, densiflorous, terminal, rarely with an axillar flower at the base of the inflorescence, 4–12 cm long, densely hirsute; bracts 6–13 mm long, lanceolate to narrowly-triangular, pilose to hirsute; flowers sessile to subsessile, pedicel erect after anthesis, 0–2 (–5) mm long, hirsute. Flowers 10–15 mm long; calyx 8.5–12 mm long, green, persistent at the fruit, externally pubescent to hirsute, internally velutine with white tector hairs only; lobes 5–9 mm long, narrowlytriangular; yellow to orange petals, standard 10–12 × 7–8.5 mm, with red veins, orbicular to wide-obovate, apex emarginated, externally pubescent, claw 4–6 × 1.5–2.5 mm, internally glabrous to pubescent at the median to basal region; wing petals 8–10 × 2–3 mm, obovate, claw 3–4 mm long; keel petals 8–9.5 × 2.5–3.5 mm, falcate, claw 3–5 mm long; ten stamens with 7.5–10 mm long, anthers orbicular to elliptic; gynoecium 9–12 mm long; ovary 3.3–4.5 mm, hirsute, 3–6 ovules. Fruit a hemicraspedia with 10–16 mm long, straight, dark brownish to black, pubescent to pilose, the trichomes white short adpressed and long black-based glandular concentered at the center of each article, (3) 4–5 article; article 2–2.5 × 2.5–3.5 mm, orbicular to elongate. Seed black, 1.5–2 × 1.5–2 mm, orbicular; white thin aril surrounding the hilum. Figs. 1 , 2 .

Additional specimens examined (paratypes)— BRAZIL. Rio Grande do Sul: Itaara, Reserva Biológica do Ibicuí-Mirim, Campo dos Barcelos , à direita da barragem, 01 Nov 1988 (fl./fr.), M. L. Abruzzi 1641 ( HAS [barcode] 24431; BOTU [bc] 34586) . São Francisco de Assis, na rodovia para Santa Maria , 23 Oct 1986 (fl.), J. Mattos 30528 ( HAS [bc] 84722) . Na rodovia de Manoel Viana para São Francisco de Assis , 23 Oct 1986 (fl.), J. Mattos 30125 ( HAS [bc] 84528) . Passo Fundo, na Fazenda Nacional Florestal , Apr. 1981 (fl.), Mattos, N. & Rosa, H. M. s.n. ( HAS [bc] 84553) . Soledade: Próximo à saída para Espumoso , 19 Dec 2008 (fr.) Iganci, J. R. V. et al. 590 ( RB 558614) .

Comments— The new species is related to A. punctata var. punctata differing by the longer bracts, calyx lobes, and flowers (fig. 3; table 1) as well as by the black fruit and arilated seed (vs. brownish fruit and not arilated seeds in A. punctata ). Both species co-occur at central Rio Grande do Sul state, but in general, A. punctata var. punctata has a southern distribution along the Brazil-Uruguay border.

The species is also similar to A. ciliata Vogel (183879), however, A. ciliata belongs to another series, Adesmia ser. Psoraleoides . Adesmia subtropicalis is distinguished by presenting adventitious roots from branch nodes and erect pedicels even after anthesis (vs. absence of adventitious roots from branch nodes and reflex pedicels after anthesis in A. ciliata ).

Distribution and habitat— Adesmia subtropicalis occurs at central-western Rio Grande do Sul state, in transition areas between Pampa (temperate) and Mata Atlantica (tropical). The species is found in shrubby grasslands ( Fig. 4 ), frequently co-occurring with other Adesmia species such as A. araujoi Burkart (1939:130) and A. ciliata , besides other herbaceous genera of legumes like Rhynchosia Loureiro (1790:425) , and Zornia .

Phenology— The species was collected with flowers from November to December (April [Mattos 30125]), and with fruits from November to January.

Conservation status— Central-western Rio Grande do Sul is a region that faces a long time ago crop pressure and lacks protected areas (J.R.V. Iganci, pers. comm., July 2021). Therefore, the species is here considered as Endangered B2ab (EN), because the area of occupancy (AOO) is under 20 km ², the populations are fragmented and there is a continuous estimated decline considering habitat degradation by agriculture and pasture.

Etymology— The specific epithet “ subtropicalis ” refers to the species distribution between Pampa (temperate) and Mata Atlantica (tropical), in subtropical southern Brazil.

Figures

FIGURE 1.A–C: Adesmia subtropicalis Cobra;A: glandular trichomes at the stem B: flower; calyx lobes longer than the corolla; glandular trichomes abundant at the lobe margins. C: racemose inflorescence; leaf pseudoimparipinnate (with an aborted leaflet at the last pair of leaflets); glandular trichomes abundant at the leaf and at the stem. Photos by Thiago Cobra e Monteiro.

FIGURE 2.A–I:Adesmia subtropicalis Cobra;A:prostrate to ascendant habit.B: densiflorous inflorescence.C: long glandular ochraceous trichomes abundant at the inflorescence. D: stipule narrow-triangular, slightly united at the base. E: paripinnate leaf, with 10 pairs of elliptic leaflets. F–I: fruit; F: calyx, with pilose lobes. G: fruit indumentum, adpressed white tector hairs and long ochraceous glandular hairs. H: fruit 5-articulated, with persistent calyx. I: short arilated seed. Voucher: M. L. Abruzzi 1641 (HAS [barcode] 24431; BOTU [bc] 34586), drawn by Klei Souza.

FIGURE 4. Geographic distribution of Adesmia subtropicalis Cobra, with a mixed occurrence between shrubby grasslands and subtropical woods (Modified from Hasenack et al. 2017).