Baccharis gibertii Baker (1882: 52)

Heiden, Gustavo & Pirani, José Rubens, 2016, Taxonomy of Baccharis subgen. Tarchonanthoides (Asteraceae: Astereae: Baccharidinae), a group from the southeastern South American grasslands and savannas, Phytotaxa 241 (1), pp. 448-450 : 448-450

9. Baccharis gibertii Baker (1882: 52) . Lanugothamnus gibertii (Baker) Deble (2012: 13) . Type:— URUGUAY. Montevideo: Santa Lucia, 1867, ♀, J. E. Gibert 814 (lectotype K, first-step lectotype designated by Barroso 1976: 63, second-step lectotype designated by Heiden & Pirani (2012a: 42) K! (000222026, right hand branch in the top)); isolectotype K! (000222026, left hand branch at the bottom). Remaining syntypes: URUGUAY. Maldonado: 7 December 1866, ♀, Cunningham (K!); s.d., ♂, P.P. King 63 (K! 000222025). Montevideo: December 1846, ♂ & ♀, J. Arechavaleta 4104 (K!); Santa Lucia, 1867, ♂, J.E. Gibert 813 (K! 000222027).

Illustration: —Malagarriga (1973: fig. 12; 1977: dessin 64). Fig. 22 , 23 .

Subshrubs 0.5–1.7 m tall, erect; fertile shoots ascending, branches axillary. Stems light brown or stramineous, shoots villose. Leaves 0.7–3.8 cm long, 0.3–1.2 cm wide, sessile, evenly distributed along the branches; leaf blade thin, cordate, ovate to oblong, apex acute, base truncate to subcordate, margins entire, slightly revolute; leaves 1- nerved, adaxial surface with a persistent sparse sericeous indumentum, abaxial surface with a persistent dense sericeous indumentum. Capitulescences racemose, terminal; 4–17 cm long, 2.5–9 cm wide. Capitula sessile to pedunculate; peduncles 0.1–1.3 cm long, villose. Male capitula 4.7–6 mm long; involucre 4.6–5 mm long, 6.7–8.3 mm wide, campanulate; phyllaries 3-seriate, light-green, outer, median and inner ones linear-lanceolate, margins entire, apex acute, pilose; clinanthium conical, densely covered with scarce filiform and biseriate trichomes; florets 38–50; corollas 3.8–4.3 mm long, tube 1.6–1.8 mm long, throat 1.4–1.5 mm, lobes 0.8–1 mm long, biseriate trichomes on the throat and filiform trichomes on the lobes; anthers light brown, 3.7–4.1 mm long; style 3.9–4.5 mm long; ovary abortive, 0.25–0.4 mm long, 0.4–0.45 mm wide, covered by twin trichomes; pappus 3.5–4 mm long, bristles 18–28, flexuous, apically not broadened. Female capitula 6.2–6.7 mm long; involucre 5–5.9 mm long, 5–6.3 mm wide, cylindrical; phyllaries 4–5-seriate, light green, outer ones ovate, median ones linear-elliptic, inner ones linear-lanceolate, margins entire, apex acute, pilose; clinanthium conical, densely covered with scarce filiform and biseriate trichomes; florets 58–86; corollas 3.4–4.1 mm long; style 4–4.7 mm long, branches 0.4–0.6 mm long. Cypselae 1.2–1.4 mm long, 0.37–0.5 mm wide, light brown, villose, evenly covered by long twin trichomes, obconical, 4–5-ribbed; pappus 3.5–7.5 mm long, deciduous; bristles 40–60, not broadened apically, strongly accrescent. Chromosome number unknown.

Etymology: —The species was named after the Uruguayan chemist José Ernesto Gibert (1818–1886), collector of the type specimen.

Distribution and habitat: — Baccharis gibertii occurs from Southern Brazil (Rio Grande do Sul state) to southeastern Uruguay (Canelones, Cerro Largo, Maldonado, Montevideo, Rocha and San José departments), known from few disjunct locations, mostly along the coastal plain or rarely inland at elevations between 0 and 150 m a.s.l. (Fig. 24). It forms dense but unevenly distributed populations, growing on sandy and periodically flooded soils, mainly along riverbanks, on acid swamps or peat bogs, within the temperate grassland biome, and in the transitional zone of the temperate grasslands and the maritime coastal vegetation types of the Pampean province.

Phenology: —Fertile specimens have been collected from October to early February, with a flowering peak between November and December.

Conservation status: —Vulnerable (VU B1; B2a; b i, ii, iii). Baccharis gibertii is represented only in few conservation units and in non-protected primary sites. The populations are naturally fragmented and the area of occupancy is restricted and decreasing. Few known populations still persist, all of them under anthropogenic pressure caused by drainage, urbanization and extraction of peat, leading to habitat suppression and loss of habitat quality. The only record in Brazil was made 60 years ago in a currently urbanized area, and a regional assessment of conservation associated with the search of new sites of occurrence in the country is needed.

Vernacular names: —Unknown.

Comments: — Baccharis gibertii is known from few sites in the surroundings of Montevideo, one additional area in the department of Cerro Largo, close to the Brazilian border, and a single old collection from southern Rio Grande do Sul, Brazil. Heering (1904), Barroso (1976) and Barroso & Bueno (2002) cite the occurrence of the species to Santa Catarina referring to the specimen Ule 1510. However, B. gibertii is not recorded from this state and the specimen cited is the type collection of B. uleana , a clearly distinct species.

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FIGURE 24. Distribution of Baccharis gibertii (□) and B. leucocephala (○).

Specimens examined: — BRAZIL. RIO GRANDE DO SUL: Pelotas , 10 November 1946, ♂, E. Maria 22 ( LP, SPF, US); ♀, E. Maria 23 ( LP, MT, P, SP, SPF, US) . URUGUAY. CANELONES: Arroyo Tropa Vieja, 7 Octubre 1965, ♂, H. A. O. Del Puerto & E. H. Marchesi 5316 ( MVFA). Balneario Jaureguiberry, 28 October 2005, ♂, F. Haretche 22 ( MVJB); ♀, F. Haretche 23 ( MVJB); Carrasco, December 1941, ♀, D. Legrand 3618 ( MVM); 6 November 1960, ♀, B. Rosengurtt 7782 ( MVFA); Ciudad de la Costa, Ruta Interbalneária, km 28, 1 November 2011, ♂, G. Heiden et al. 1757 ( GB, ICN, MBM, MVFA, RB, SPF); ♀, G. Heiden et al. 1758 ( BHCB, FLOR, GB, K, LP, PEL, SPF); El Pinar, 7 December 1962, ♀, H. A. O. Del Puerto 2260 ( K, MVFA); 21 December 1972, ♀, A. Lombardo & H. A. O. Del Puerto s.n. ( MVFA 11896 ); Arroyo Pando, 300 m de la Interbalnearia, 10 Octubre 2004, bud, C. Callero & F. Ferreyro 77 ( MVJB); 24 Octubre 2004, ♂ & ♀, C. Callero & L. Dominguez 157 ( MVJB); 1 November 2011, ♂, G. Heiden et al.1759 ( GB, RB, SPF); ♀, G. Heiden et al. 1760 ( GB, MBM, MVFA, RB, SPF, US). Pando , 8 November 1947, ♂, A. L. Cabrera & D. Legrand 2672 ( LP, MVFA); December 1944, ♀, A. Lombardo s.n. ( LIL 206914 ); December 1946, ♀, A. Lombardo 3806 ( MVJB); November 1947, ♂, A. Lombardo 4052 ( MVJB); 12 January 1944, ♀, B. Rosengurtt 4326 ( MVFA). Bañado del Negro , Arroyo Pando , 1 December 1946, ♀, A. Castellanos 17223 ( CTES, LIL); Interbalnearia km 27, El Palmar , 29 Octubre 2000, ♀, E. Alonso Paz & J. Bassagoda 3415 ( MVFQ); 6 December 2000, ♂, E. Alonso Paz & J. Bassagoda 3071 ( MVFQ). CERRO LARGO: Sierra de Ríos , 27 November 2011, ♀, M. Bonifacino 4091 ( MVFA, SPF). MALDONADO: 7 December 1866, ♀, Cunningham s.n. ( K); s.d., ♂, P. P. King 63 ( K). MONTEVIDEO : Santa Lucia, November 1811, ♂ & ♀, J. Arechavaleta 4104 ( LP, MVM); December 1846, ♂ & ♀, J. Arechavaleta 4104 ( K); 30 October 1900, ♂, M. B. Berro 1772 ( MVFA, P); 1872, ♀, M. Fruchard s.n. ( P03159282 ); 1896, ♂ & ♀, M. Fruchard s.n. ( LP, MVFA, SI, P 03159286 ); 1867, ♂, J. E. Gibert 813 ( K); ♀, J. E. Gibert 814 ( K). ROCHA: Sierra de Ríos , 27 November 2011, ♀, M. Bonifacino 4091 ( MVFA, SPF). SAN JOSÉ: Barra de Santa Lucía, February 1876, ♂ & ♀, J. Arechavaleta s.n. ( MVM 2120 , 2121 , 2122 , 2123 ); November 1940, ♀, J. Chebataroff 2268 ( MVM); s.d., ♀, J. Chebataroff 3701 ( LP); March 1926, st., A. Lombardo 799 ( MVJB); December 1927, ♀, A. Lombardo 1063 ( MVJB); 9 February 1919, ♀, C. Osten 14759 ( MVM); 28 October 1947, ♂, B. Rosengurtt 5047 ( LIL, LP, MBM, MVFA, MVM). S.l., September 1870, st., A. Arechavaleta s.n. ( P03159285 ). S.l., s.d., D. Legrand 4566 ( MVM) .

TAXONOMY OF BACCHARIS SUBGEN. TARCHONANTHOIDES

Figures

FIGURE 22. Baccharis gibertii. A. Fertile shoot of pistillate plant. B. Leaves. C. Portion of villose peduncle. D. Male capitulum. E. Phyllaries of male capitulum (outer to inner). F. Male floret. G. Female capitulum. H. Phyllaries of female capitulum (outer to inner). I. Female floret. J. Corolla and style of female floret. K. Cypsela. A, C, G–K: Heiden 1760 (SPF). B (from left to right): Maria 23 (PEL); Berro 1772 (MVFA); Heiden 1759 (SPF); Arechavaleta 4104 (LP). D–F: Heiden 1759 (SPF). Illustration by João Iganci.

FIGURE 23. Baccharis gibertii. A. Habitat in a peat bog in the transitional zone of the temperate lowland grasslands and the maritime coastal vegetation at Balneario El Pinar, Ciudad de la Costa, Canelones, Uruguay. B. Habit. C. Shoots. D. Male capitulescence. E. Female capitulescence. Photos by G. Heiden.