Adesmia miottoae Cobra, Iganci & Fort-Perez, 2021

Cobra, Thiago, Iganci, João Ricardo Vieira, Seixas, Diana Pacheco, Rodrigues, Tatiane Maria & Fortuna-Perez, Ana Paula, 2021, A New Species of Adesmia (Leguminosae, Papilionoideae, Dalbergieae) from Southern Brazil, with Notes on Leaf Anatomy, Phytotaxa 521 (1), pp. 48-56 : 49-54

Adesmia miottoae Cobra, Iganci & Fort-Perez , sp. nov.

TYPE:— BRAZIL. Santa Catarina: São Joaquim, SC-114 [-28.225333°, - 49.986972 °], 01 december 2020 (fl. fr.) T. Cobra & G.M. Cobra 344 (holotype BOTU! ; isotypes ICN!; MBM!; PEL!; RB!; UEC!) .

Diagnosis—Pubescent indumentum with short glandular hairs up to 0.4 mm long, leaflets obovate, 2.3–9.8 × 2–3.5 mm, inflorescence lax to congested at the top, flowers (8.5–) 10–14 mm long, sessile to subsessile, pedicel 0–3 mm long, calyx lobes 4–7 mm long, standard claw 5.5–7 mm, hemicraspedium with 5–7 ovules. This is similar to A. incana Vogel (1838: 76) and A. punctata ( Poiret 1804: 447) De Candolle (1825: 95) , which has longer glandular trichomes (1 mm long at the stem) and pedicel (2–8 mm long in A. incana and 0–8 mm long in A. punctata ), besides having shorter standard claws (3.5 (–5) mm long in A. incana and 3–5 mm long in A. punctata ) and less ovules (4–5 in A. incana and 3–5 in A. punctata ).

Prostrate, woody-based perennial herb with adventitious roots from stem branch nodes, stems appressed-pubescent with short glandular and non-glandular hairs intermixed on all plant parts. Leaves alternate, paripinnate, 8–10 (–12) pairs of opposite leaflets, pubescent. Stipules 3–5 × 0.5–1.5 mm, persistent, linear to strait-triangular, pubescent. Petiole 5–23.5 mm long, rachis 13–45 mm long, both cylindrical and sulcate at the adaxial face. Leaflets 2.3–9.8 × 2–3.5 mm, obovate, apex retuse to mucronate, base cuneate to rounded, pubescent in both faces. Raceme terminal, 7–40 cm long, pubescent; bracts 3–4 mm long, lanceolate, pubescent, flowers sessile to subsessile. Flowers yellow with red nectar guides, hermaphrodite, (8.5–) 10–14 mm long; calyx campanulate, 5.5–9 mm long, 5-lobed, externally pubescent; the carenal lobe 4.4–7 mm long, others 4–5.4 mm long, linear; corolla papilionaceous; standard petal 10.5–13 × 7–8.5 mm, orbicular, externally pubescent, claw 5.5–7 × 1–1.5 mm, internally pubescent near the lamina; wing petals 9.0–10.5 × 2.5–3.5 mm, obovate, claw 3.5–4.5 mm long; keel petals 8–9.5 × 2.5–3.5 mm, falcate, dorsally ciliate, claw 3–4.5 mm long; stamen 10, 2 adnate at the standard claw, the others free, 8–10 mm long, anthers elliptical to orbicular, dorsifixed; gynoecium 10–12.5 mm long, ovary straight, 3–4.5 mm long, pubescent, 5–7 ovules. Fruit hemicraspedium, 3–6 articles, straight, brownish, 8.5–13 mm long, pubescent to pilose, with black-based glandular trichomes at the center of each article; articles 2–2.7 × 2.5–3.5 mm, orbicular. Seeds brownish, 1.5–2 × 1.5–2 mm, orbicular; hilum orbicular, no aril. Figs. 1 , 2 .

Additional Specimens Examined (paratypes): — BRAZIL. Rio Grande do Sul: Bom Jesus, fazenda dos Potreirinhos , 4 December 1977 (fl. fr.), O. R. Camargo 5612 ( HAS) . Lagoa Vermelha, 19 Km a Sudoeste da Vila Tupinambá , ao longo da estrada Nova Prata para Barretos, 8 December 1986 (fl. fr.), J. F. M. Valls 10758 ( UEC) . São José dos Ausentes, Morro do Chorão [−28.488611°, −49.801111°] 26 September 2014 (fl.), J. Cordeiro 5292 ( HUCS, MBM, FLOR, ICN) . Vacaria, estrada para Bom Jesus , 24 january 1990 (fl.), L. A. Z. Machado & A. Polking 512 ( SMDB) . Santa Catarina: Bom Jardim da Serra, proximidades da Cascata da Barrinha , 4 Km a SE de Bom Jardim, 23 november 1984 (fl. fr.), J. F. M. Valls et al. 7995 ( ICN, UEC) ; Capão Alto, SC 458 Km 179 , 30 October 1999 (fl.), S. T. S. Miotto 1764 ( ICN) . Painel, Estrada para São Joaquim , 14 January 2009 (fl./fr.), J. R. V. Iganci et al. 647 ( ICN, RB) . Urubici, 17 November 2008 (fl.), J. R. V. Iganci et al. 475 ( CTBS) . São Joaquim, 5,3 Km a sudeste de Cruzeiro e 3,1Km a noroeste de Rio Mantiqueira , 30 November 1989 (fl. fr.), J. F. M. Valls et al. 12126 ( ICN, UEC) .

Distribution and Habitat: — Adesmia miottoae is frequent in the highland grasslands of southeastern Santa Catarina state (municipalities of Urubici, São Joaquim) ( Fig. 4 ) and northeastern Rio Grande do Sul state (municipalities of Vacaria, Bom Jesus, São Francisco de Paula). The species is less frequent in other regions of Rio Grande do Sul, in the Pampa grasslands. So far, this species has not been found in Uruguay and Argentina, being endemic to southern Brazil. Adesmia latifolia ( Sprengel 1826: 322) Vogel (1838: 74) and A. miottoae are the only species of the Bicolores series that occur in Santa Catarina state ( Fig. 3 ).

Conservation Status: — Adesmia miottoae is widely distributed between Rio Grande do Sul and Santa Catarina states, with an estimated Extent of Occurrence (EOO) of 109.149,84 km² and with an Area of Occupancy (AOO) of 120 km ². The species is well sampled in herbarium collections and was recently collected in three protected areas: Parque Nacional de São Joaquim, Parque Nacional da Serra Geral and Área de Proteção Ambiental do Ibirapuitã. This led us to consider the species as Least Concern (LC) because its present situation does not qualify for any of the categories of threat provided by the IUCN Red List criteria ( IUCN 2019).

Phenology: — The species was collected with flowers from September to January, and with fruits from November to February.

Etymology: —The epithet honors Professor Silvia Terezinha Sfoggia Miotto for her great contribution to Adesmia studies in Brazil, as part of the important work she undertook with the Leguminosae family as a whole, especially in the Rio Grande do Sul state, Brazil.

Taxonomic notes: — Adesmia miottoae is remarkable due to the short glandular trichomes (up to 0.4 mm) densely covering all the aerial parts of the plant with the exception of the fruit (which present 1 mm long trichomes) and the corolla ( Fig. 2 ). The species is closely related to A. incana var. incana , diverging with the pedicel, calyx lobes and standard claw length, number of ovules and indumentum ( Tab. 1 ). Additionally, A. miottoae presents a carenal lobe longer than other lobes and a calyx measuring almost the same length as the corolla ( Fig. 2 ), while A. incana has a calyx with equal lobes reaching half of the corolla length ( Vogel 1838). Also, A. incana stem has 1 mm long glandular trichomes, while A. miottoae stem has only short glandular trichomes (up to 0.4 mm long).

Adesmia miottoae also resembles A. punctata ( Poiret 1804: 447) De Candolle (1825: 95) var. punctata and A. punctata var. hilariana Bentham (1859: 54) , from which it can be distinguished by obovate leaflets 2–3.5 mm wide (vs. elliptic leaflets 1–2 mm wide in both A. punctata var. punctata and A. punctata var. hilariana ) and flowers (8.5–) 10–14 mm long (vs. 8–10 mm long in A. punctata varieties). Besides, A. punctata var. punctata has 1 mm long glandular hairs (vs. up to 0.4 mm long in A. miottoae ), and A. punctata var. hilariana has 4–8 mm long pedicels (vs. sessile to subsessile flowers in A. miottoae ). The characters used to distinguish between the four taxa can be found in Table 1 .

Several herbarium sheets that correspond to A. miottoae were previously identified as A. ciliata Vogel (1838: 74) , a species from the series Psoraleoides Burkart (1967: 506) . These two species occur in sympatry and can be easily differentiated by the adventitious roots from branch nodes of A. miottoae (vs. absence of adventitious roots in A. ciliata ), by the pubescent indumentum in A. miottoae (vs. hirsute in A. ciliata ) and by the erect pedicels of A. miottoae when fruiting (vs. reflex pedicels in the fruits of A. ciliata ).

Anatomical Notes of the New Species: — The leaflet blade of A. miottoae is covered by a uniseriate epidermis with ordinary cells varying in shape from isodiametric to tangentially elongated ( Fig. 5a ). Epidermal cells containing mucilage occur on both leaflet surfaces and the leaflet edges ( Fig. 5a ). These cells react positively to Ruthenium red histochemical test ( Fig. 5a , insert). Leaflets are amphistomatous ( Fig. 5a ) and the stomata complexes are anisocytic ( Fig. 5b ). Glandular multiseriate trichomes occur on both surfaces of the leaflet blade ( Fig. 5c, d ). These trichomes consist of a basis with three to four isodiametric to slightly elongated cells inserted in the epidermal line ( Fig. 5e , left insert); a stalk with an enlarged and multicellular lower portion followed by a narrowly elongated portion with two to four cells in pairs ( Fig. 5e ); and a reduced unicellular and rounded secretory head ( Fig. 5d , right insert).

The mesophyll is dorsiventral, composed of two to four layers of palisade parenchyma on the adaxial leaflet surface and three to four layers of spongy parenchyma on the abaxial leaflet surface ( Fig. 5a, d ). The leaflet is homobaric and the collateral vascular bundles immersed in the mesophyll ( Fig. 5a, d ) are interconnected by paravenal parenchyma ( Fig. 5a, c ) with voluminous cells filled with phenolic compounds, which stained in green with toluidine blue ( Fig. 5d ).

The contour of the midrib region is concave on the adaxial leaflet surface and slightly convex on the abaxial leaflet surface ( Fig. 5f ). The epidermal cells vary from rounded to rectangular on the adaxial surface and from rounded to oval in shape on the abaxial surface of the midrib ( Fig. 5f ). The cortex comprises two layers of palisade parenchyma on the adaxial surface and two to three layers of spongy parenchyma on the abaxial surface ( Fig. 5f ). The endodermis comprises voluminous parenchyma cells ( Fig. 5f ). The vascular system is reduced and shows a collateral vascular bundle in a semi-arc shape ( Fig. 5f ).

Figures

FIGURE 1. Adesmia miottoae. A Papilionoid flower with red nectar veins; B Calyx equalizing the corolla in length. Calyx lobes longer than the tube; C Corolla, with petals fused at the base; D Pinnate leaf with seven pairs of leaflets; E Developing fruit with a persistent calyx. Photos by Thiago Cobra e Monteiro.

FIGURE 2. Adesmia miottoae A Paripinnate leaves, leaflets obovate; B Leaflet; abaxial face pubescent with glandular and non-glandular trichomes; C Leaflet; adaxial face pubescent, short glandular trichomes at the blade; D Short glandular trichomes; E Flower; calyx lobes longer than the tube; F Calyx indumentum; glandular and non-glandular hairs present; G Hemicraspedium fruit; H Spherical article with glandular and non-glandular hairs intermixed. (Voucher: Cobra, T. M. & Cobra, G. M. 341).

FIGURE 3. Distribution of Adesmia miottoae based on herbarium sheet labels. A South America. B Close up in Rio Grande do Sul and Santa Catarina states, Brazil, with black dots marking where the species were collected.

FIGURE 4. Adesmia miottoae habitat. A roadside in São Joaquim, SC, Brasil. B population of A. miottoae inside São Joaquim National Park. C São Joaquim National Park. Photos by Thiago Cobra e Monteiro.

FIGURE 5. Cross (A, C-F) and paradermal (B) sections of A. miottoae leaflet blade. A Leaflet blade stained with toluidine blue showing uniseriate epidermis and dorsiventral mesophyll with paravenal parenchyma. Observe mucilaginous cells in the epidermis.The inset show mucilaginous cells stained with Ruthenium red in the epidermis; B Frontal view of the abaxial leaflet surface showing anisocitic stomatal complex stained with Safrablau; C Leaflet blade stained with Safrablau showing trichomes (black arrows) on both leaf surfaces; D Leaflet blade stained with toluidine blue showing dorsiventral mesophyll and paravenal parenchyma cells containing phenolic compounds; E Detail of glandular trichome stained with Safrablau consisting of basis, stalk and reduced head. The left insert shows basal cells stained with toluidine blue and the right insert shows detail from the outline of secretory head stained with Safrablau; F Midrib with vascular tissues surrounded by voluminous endodermal cells. Basal trichome cells (Bc), endodermis (Ed), mucilaginous cells (Mc), palisade parenchyma (Pp), paravenal parenchyma (Pv), phloem (Ph), secretory head (Sh), spongy parenchyma (Sp), stalk cells (Sk), stomata (St), xylem (Xy). Scale bars: 150 µm (A, C, D), 100 µm (F), 50 μm (B, E).