Austroeupatorium inulifolium (Kunth) King & Robinson (1970: 434)

Mailhos, Ary, Cosse, Mariana, Pérez, Camilo & Bonifacino, José Mauricio, 2025, Taxonomic revision of Austroeupatorium (Compositae, Eupatorieae) in Uruguay: new records and a new combination, Phytotaxa 683 (2), pp. 119-132 : 121-127

Austroeupatorium inulifolium (Kunth) King & Robinson (1970: 434) . Eupatorium inulifolium Kunth (1818: 85) ,

as “inulaefolium”. Type:— Colombia. Mariquita, June 1801, F.W.H.A. Humboldt & A.J.A. Bonpland (holotype, P

[P00320054!]). ( Fig. 1 ; Fig. 2 A, D )

= Eupatorium molle Kunth (1818: 85) , nom. illeg., non Swartz (1788: 111). Type:— Colombia. Mariquita, June 1801, F.W.H.A. Humboldt & A.J.A. Bonpland (holotype, P [P00320055!]).

= Eupatorium suaveolens Kunth (1818: 86) . Eupatorium inulifolium f. suaveolens (Kunth) Hieronymus (1901: 572) , as “inulaefolium”. Type:— Colombia. Near Santa Ana, Mariquita, Ibagué, 1801, F.W.H.A. Humboldt & A.J.A. Bonpland (holotype, P [P00320056!]).

= Eupatorium pallescens Candolle (1836: 154) . Type:— Brazil. Minas Gerais, Sabará, 1833, A.C. Vauthier 273 (holotype, P [ P00742447 !]; isotypes, G-DC [ G00494200 !], GH [ GH00007873 !]).

= Eupatorium pallescens var. hirsutum Candolle (1836: 154) . Type:— Brazil. Rio Grande do Sul, 1833, F. Sellow , Herb. Imp. Bras. 789 (holotype, P [ P02476510 !]; isotype, G-DC [ G00494201 !]).

= Eupatorium pallidum Hooker & Arnott (1836: 241) . Eupatorium pallescens var. bonariense Candolle (1838: 269) . Type:— Argentina. Buenos Aires, J. Tweedie (lectotype, E [E00249932!], designated by Grossi [2014: 311]; isolectotype, G-DC [G00465963!]).

= Eupatorium paranense Hooker & Arnott (1836: 241) . Type:— Argentina. Buenos Aires, J. Tweedie (lectotype, E [E00249924!], designated by Grossi [2014: 311]).

= Eupatorium entreriense Hieronymus (1897: 767) . Austroeupatorium entreriense (Hieron.) King & Robinson (1970: 434) . Type:— Argentina. Entre Ríos, Concepción del Uruguay, June 1877, P.G. Lorentz 1038 (syntypes, B†, negative F [F0 BN016257 !], CORD [CORD00005333!, CORD00005334!, CORD00005335!, CORD00005336!], GH [GH00007652!], S [S-R-9001!]).

Subshrubs (0.5–) 1–2 m tall, stems erect, distally branched, cylindrical, pubescent and glandular. Leaves opposite, sometimes subopposite or alternate in inflorescences, 53–110 x 17–38 mm, petioles 6–21 mm long, laminas ovate or narrowly ovate, entire, base cuneate and decurrent along the petiole, apex acute or obtuse, laxly pubescent on the adaxial surface, pubescent and glandular on the abaxial surface, with three prominent veins from or near the base, herbaceous, slightly discolorous, margin subentire or serrate, slightly revolute. Capitula homogamous, numerous, grouped in terminal corymbiform capitulescences, peduncles 1–4.5 mm long, pubescent and glandular, with ascending trichomes, bracts 0 to 2 on peduncles, narrowly oblong. Involucres 5–6.5 x 2–2.5 mm, cylindrical, subimbricate, phyllaries in 3 or 4 series; outer phyllaries ovate, base obtuse, apex rounded, pubescent and glandular, membranaceous, margin undifferentiated, ciliate; inner phyllaries narrowly obovate, base attenuate, apex rounded, pubescent at the apex, membranous, margin membranous, ciliate. Receptacles epaleate, flat or somewhat convex, scrobiculate. Florets 11 to 13, perfect; corollas tubulose, funnelform, 3.8–4.4 mm long, white, glandular at the base, lobes 5, 0.4–0.5 mm long, broadly ovate, externally glandular; anther collars oblong, anthers 1.3–1.6 mm long, base obtuse, connective appendage ovate, apex rounded; styles 5.6–7.2 mm long, base straight, pubescent, style branches 2.9–3.7 mm long, filiform, papillate, stigmatic surfaces 1–1.3 mm long, sterile appendage 1.8–2.3 mm long. Cypselae 1.8–2.7 mm long, obpyramidal, 5-nerved, surfaces glandular or glabrous, black; carpopodia symmetric-cylindrical, about as long as wide, 0.2–0.3 mm long with subquadrate and oblong cells. Pappus 2.3–2.8 mm long, composed of 33 to 45 white, scabrid bristles, arranged in 1 series.

Distribution and habitat: —Neotropical, from Central America to northern and eastern Argentina, southern Brazil and Uruguay ( Grossi 2014, Robinson 2018), where it is found throughout the country ( Fig. 3 ). Within Uruguay it grows in humid fields, adjacent to rivers and streams, in forest margins and clearings, and in disturbed sites such as railways and roadsides.

Common name: —”Mariposera blanca”.

Phenology: —Flowering from late January to early May; fruiting from late February to May.

Notes: — Austroeupatorium inulifolium was first reported for Uruguay by Gibert (1873) (under Eupatorium pallescens ). It is a very conspicuous species during its flowering season due to its abundance across most of the country and its perfumed flowers.

Specimens examined: — URUGUAY. Artigas: Cuareim, March 1902, M.B. Berro 1581 (MVFA). Cuareim, 8 March 1903, M.B. Berro 2525 (MVFA). Camino a San Gregorio, 30°32’36.60’’S, 57°49’27.20’’W, 22 March 2017, C. Pérez et al. 187 (MVFA). Canelones: Toledo, s.d., J. Chebataroff 2105, 5009 (MVJB). Campos de La Paz, March 1925, L. Marchesi s.n. (MVJB 1106, 10558). Ibid., L. Marchesi s.n. (MVJB 10558). Balneario Argentino, 34°47’31.50’’S, 55°26’56.10’’W, 30 March 2015, F. Haretche 862 (MVJB 29476). Colonia: S.loc ., April 1926, G. Herter s.n. (MVMHerb. Osten 18889, 18890). El Caño, April 1926, G. Herter s.n. (MVM-Herb. Osten 18878, 18891). Nueva Palmira, April 1926, G. Herter s.n. (MVM-Herb. Osten 18856, 18892).Arroyo San Juan, April 1947, A. Lombardo 3949 (MVJB 10419). Ibid., A. Lombardo 3984 (MVJB 10518). Ibid., A. Lombardo 4429 (MVJB 10562). Carmelo, 18 January 1962, B. Rosengurtt et al. 8580 (MVFA). Nueva Helvecia, 28 March 1963, O. Del Puerto 72 (MVFA). Ruta 1 y arroyo de la Caballada, 27 April 1973, O. Del Puerto & H. Rodríguez s.n. (MVFA 12062). Al NE de Tarariras, 27 April 1973, O. Del Puerto & H. Rodríguez s.n. (MVFA 12064). Carmelo, balneario Zagarzazú, 33°57’57.70’’S, 58°20’03.60’’W, 13 May 2005, C. Brussa et al. s.n. (MVJB 30540). Florida: Isla Mala, March 1934, A. Lombardo 1368 (MVJB 10415); Ibid., A. Lombardo 1369 (MVJB 10416). Fray Marcos, 34°12’52.90’’S, 55°44’35.20’’W, 18 April 2017, C. Pérez et al. 256 (MVFA). Lavalleja: Minas, 30 March 1907, C. Osten 4508 (MVM). Minas, arroyo Campanero, April 1925, A. Lombardo 510 (MVJB 10422). Maldonado: Perdomo, 6 March 1885, C. André s.n. (MVM 2495). Aiguá, Cerro de la Salamanca, 26 March 1939, B. Rosengurtt B-2899 s.n. (MVFA). Sierra de Carapé, Zanja del Tigre, 7 April 2004, L. Dominguez s.n. (MVJB 23149). Montevideo: Toledo Chico, s.d., J. Chebataroff 2562 (MVJB). Barra de Santa Lucía, March 1875, J. Arechavaleta s.n. (MVM 2498). S.loc ., 1878, J.E. Gibert s.n. (MVM 2497). S.loc ., April 1965, A. Lombardo 6095 (MVJB 10418). Parque Lecocq, 23 November 1980, E. Alonso Paz 66 (MVM 2203). Facultad de Agronomía, 10 May 2005, C. Brussa s.n. (MVJB 22446). Paysandú: Agronomía, 21 March 1940, B. Rosengurtt B-3370 (MVFA). Al sur de Estación Quebracho, 12 March 1971, O. Del Puerto & E. Marchesi s.n. (MVFA 10423). Estación experimental M. Cassinoni, 11 May 1973, O. Del Puerto s.n. (MVFA 12080). Río Negro: San Javier, s.d., J. Chebataroff 4572 (MVJB). Cerca de Paso del Puerto, 22–28 March 1964, E. Marchesi 1218 (MVFA). Río Negro y arroyo Yapeyú, campo Vichadero, 12 April 1994, E. Marchesi & M. Vignale (s.n. MVFA 23317). Young, planta de Claldy S.A., 21 March 2006, M. Piaggio s.n. (MVJB 23970). Rivera: Arroyo Curticeiras y vía férrea, 14 March 1962, O. Del Puerto s.n. (MVFA). Paso del Apretado, cuchilla de Cerros Blancos, 26 March 1988, I. Berrutti s.n. (MVFA 20053). Cuchilla Negra, arroyo del Potrero, 31º02’S, 55º48’W, 28 March 1998, J.M. Bonifacino & L. Profumo s.n. (MVFA 28388). Rocha: Entre La Paloma e India Muerta, January 1926, J. Schroeder s.n. (MVM-Herb. Osten 19447). Fortaleza Santa Teresa, March 1938, A. Lombardo 3410 (MVJB 10420). Santa Teresa, 23 March 1966, O. Del Puerto & E. Marchesi 6093 (MVFA). Arroyo Don Carlos, March 1938, A. Lombardo 2907 (MVJB 10421). San Luis, 15 January 1995, L. Delfino s.n. (MVJB 21142). Salto: San Antonio, 22 March 1910, C. Osten 5477 (MVM). Arroyo Valentín Grande y ruta 1, 20 February 1991, s.coll. (MVFA 20129). San José: Rincón de Arazatí, 24 March 1935, D. Legrand 491 (MVM). Barra de Santa Lucía, 12 April 1947, D. Legrand 1982 (MVM). Barra de Santa Lucía, 19 April 1947, D. Legrand 1998 (MVM). Autódromo, 21 April 1964, O. Del Puerto 3372 (MVFA). Desmbocadura del arroyo Cufré, 28 February 1967, O. Lema s.n. (MVFA 6498). Soriano: Mercedes, Cololó, 10 April 1893, C. Osten 3062 (MVM). Vera, 28 March 1900, M.B. Berro 2114 (MVFA). Vera, 20 March 1901, M.B. Berro 2115 (MVFA). San Salvador, 18 March 1908, M.B. Berro 4998 (MVFA). Mercedes, 13 March 1913, M.B. Berro 3031 (MVFA). Vera, April 1915, M.B. Berro 8039 (MVFA). Juan Jackson, estancia Santa Elena, March 1936, B. Rosengurtt B-321 (MVFA). Monzón- Heber, 17 April 1940, A. Gallinal et al. PE-4322 (MVFA). Ruta 14 antes del empalme con la 55, cruce del arroyo del Estaqueadero, 33°14’16.10’’S, 57°19’25.90’’W, 21 March 2017, C. Pérez et al. 126 (MVFA). Tacuarembó: Bañado de Rocha, paso Lambaré, 22–28 March 1921, J. Schroeder s.n. (MVM-Herb. Osten 16072). Paso de los Toros, March 1937, B. Rosengurtt B-1251 (MVFA).

Additional specimens examined: — ARGENTINA. Corrientes: General Paz, 9 April 1972, L. Mroginski et al. 552 ( UB 33625). Misiones: San Ignacio, 10 April 1956, J. E. Montes s.n. ( UB 33626).— BRAZIL. Minas Gerais: Ca. 27 km SE of Coroaci along highway MG-109, 28 March 1976, G. Davidse et al. 11469 ( MO). Paraná: Telémaco Borba, Estrada do BRS, 24º19’48’’S, 50º34’26’’W, 18 April 2009, A. G. Faraco et al. 501 ( RB 649144). Rio de Janeiro: Niterói, Itaipu, Maravista, 27 March 2002, T. A. Machado et al. 03 ( RB 811413). Rio Grande do Sul: Caxias do Sul, April 1986, G. Grazziotin 1626 ( MO). Santa Catarina: Bombinhas, Bairro de Bombas, 05 May 2005, M. G. Caxambu 782 ( IBGE 62918). São Paulo: Municipio de Ibiuna, 03 April 1981, K. Mizoguchi 1581 ( MO).

Austroeupatorium laetevirens (Hook. & Arn.) King & Robinson (1970: 434) . Eupatorium laetevirens Hooker & Arnott (1836: 240) . Eupatorium steviifolium var. laetevirens (Hook. &Arn.) Baker in Martius (1876: 319). Syntypes:— Brazil. Rio Grande do Sul, J. Tweedie (E [E00433290!]); S. Brazil, J. Tweedie (K [K000488984!], photo W [W1976- 0014056!]). ( Fig. 2 B, E ; Fig. 4 ) = Eupatorium steviifolium var. salicinum Chodat in Chodat & Hassler (1903: 710). Type:— Paraguay. Atyrá “In dumetis”, E. Hassler

4023 ( lectotype, UC [ UC935204 !], designated by Grossi [2014: 313]; isolectotypes, G [ G00381867 !, G00381941 !, G00381942 !,

G00381943!], NY [NY00169211!], P [P00742675!, P00742676!, P00742678!], UC [UC944606!]).

Shrubs 0.6–2 m tall, stems erect, distally branched, cylindrical, pubescent when young, glabrescent or glabrous when mature. Leaves opposite, sometimes subopposite or alternate in inflorescences, 32–88 x 4–13 mm, sessile or subsessile, petioles up to 2 mm long, laminas narrowly elliptic or linear, entire, base acute, apex acute, laxly pubescent on margins and veins on both sides, with a single prominent vein on the abaxial surface, chartaceous, slightly discolorous, margin serrate in the upper 2/3, revolute. Capitula homogamous, numerous, grouped in terminal corymbiform capitulescences, peduncles 2–7 mm long, pubescent, with ascending trichomes, bracts 0 to 2 on peduncles, narrowly oblong. Involucres 4–4.5 x 3–4 mm, campanulate, subimbricate, phyllaries in 3 or 4 series; outer phyllaries narrowly oblong or elliptic, base truncate, apex rounded or obtuse, glabrous, membranaceous, margin undifferentiated, ciliate; inner phyllaries narrowly obovate, base attenuate, apex rounded, shortly pubescent at the apex, membranous, margin membranous, ciliate. Receptacles epaleate, convex, foveolate. Florets 20 to 26, perfect; corollas tubulose, funnelform, 2.7–3.2 mm long, white, glandular at the base, lobes 5, 0.4–0.5 mm long, broadly ovate, externally glandular; anther collars oblong, anthers 0.9–1.2 mm long, base obtuse, connective appendage ovate, apex rounded; styles 3.8–4.8 mm long, base straight, papillate, style branches 2.2–2.7 mm long, filiform, papillate, stigmatic surfaces 1–1.2 mm long, sterile appendage 1–1.7 mm long. Cypselae 1.3–1.8 mm long, obpyramidal, 5-nerved, surfaces glandular, black; carpopodia symmetric-cylindrical, longer than wide, 0.2–0.3 mm long with subquadrate and oblong cells. Pappus 2.3–2.8 mm long, composed of 24 to 29 white, scabrid bristles, arranged in 1 series.

Distribution and habitat: —Southern Brazil, northeastern Argentina, Paraguay ( Cabrera 1996, Grossi 2014) and northwestern Uruguay, in the Cerro Largo and Rivera departments ( Fig. 3 ). Within Uruguay it is found growing in grasslands on waterlogged soils or acidic wetlands.

Phenology: —Flowering from late February or March; fruiting from late March.

Discussion: — Austroeupatorium laetevirens differs from other species of Austroeupatorium by its narrowly elliptic to almost linear leaves with sharply serrate margins, a single prominent vein abaxially, and its glabrescent nature with very sparse indumentum, completely lacking glandular trichomes on stems, leaves and phyllaries.

Its presence in Uruguay has been known for some time from a single collection (E. Marchesi pers. comm.), and is formally documented here for the first time. During the course of this study, additional unidentified or misidentified specimens of this species were discovered in herbaria, and new collections were also made.

Austroeupatorium laetevirens has been frequently misidentified as Hatschbachiella tweedieana ( Hooker & Arnott 1836: 242) King & Robinson (1972: 394) in herbaria, and vice versa ( King & Robinson 1972, 1987). Austroeupatorium laetevirens differs from Hatschabachiella mainly by its sessile or subsessile leaves (vs. distinctly petiolate leaves), glabrescent phyllaries (vs. densely pubescent and glandular phyllaries), and glandular cypselae with elongated carpopodia (vs. setulose and glandular cypselae with annular carpopodia).

Specimens examined: — URUGUAY. Cerro Largo: Paso Centurión, establecimiento Las Bandurrias, 32°08’31.10’’S, 53°46’37.50’’W, 27 March 2024, A. Mailhos et al. 750 (MVFA). Rivera: Arroyo Sauzal, camino a Portones Negros, 28 March 1985, E. Marchesi et al. s.n. (MVFA 17560). Reserva Batoví, COFUSA, 31º02’05.30’’S, 55º24’48.30’’W, 5 March 2009, C. Brussa & F. Muñoz s.n. (MVJB 28621). Camino de Tranqueras a FYMNSA, 31°06’00.40’’S, 55°44’47.40’’W, 8 March 2018, C. Brussa et al. s.n. (MVJB 31447). Próximo a Batoví Dorado, 31°02’06.60’’S, 55°24’49.60’’W, 21 February 2020, J.M. Bonifacino & L. Majure 6876 (MVFA).

Additional specimens examined: — ARGENTINA. Corrientes: San Miguel, 22 April 1982, S. G. Tressens et al. 2074 ( ICN 59828). San Martín, Cambá Trapo, 28º32’00’’S, 57º05’00’’W, 26 April 2006, M. M. Arbo et al. 9138 ( CTES).— BRAZIL. Minas Gerais: Fervedouro, Córrego Água Limpa, 26 April 2006, L. S. Leoni et al. 6457 ( RB 659074). Paraná: Curitiba, Pinheirinho, 21 March 1962, G. Hatschbach 8912 ( RB 118239). Curitiba, Rod. do Xisto, Rio Barigui, 17 March 1971, G. Hatschbach 26526 ( MO). Rio Grande do Sul: Cambará do Sul, Itaimbezinho, 11 April 1977, S. Boechat 59 ( ICN 43315). Esmeralda, 15 April 1978, L. Arzivenco 20 ( ICN 64989). Arroio dos Ratos, 23 April 1981, K. Hagelund 13504 ( ICN). Tramandaí, 6 April 1983, B. Irgang s.n. ( ICN 53580). Osório, Lagoa da Emboaba, 29º57’58’’S, 50º13’37’’W, 18 April 2015, F. Gonzatti & E. Valduga 1752 ( MBM).

Figures

FIGURE 1. Austroeupatorium inulifolium. A. Habit. B. Capitula, lateral view. C. Leaf, adaxial surface. D. Leaf, abaxial surface. E. Cypsela, from O. Del Puerto 3372 (MVFA). A–D by J.M. Bonifacino.

FIGURE 2. Floral microcharacters in Austroeupatorium. A–C.Anther collars, note the characteristic annular thickenings in the cell walls. D–F. Style bases. A, D. A. inulifolium. B, E. A. laetevirens. C, F. A. steviifolium.

FIGURE 3. Distribution map of Austroeupatorium species in Uruguay.

FIGURE 4. Austroeupatorium laetevirens. A. Habit. B. Capitula, lateral view. C. Leaf, adaxial surface. D. Leaf, abaxial surface. E. Cypsela.A–D from A. Mailhos et al. 750 (MVFA); E from E. Marchesi et al. (MVFA 17560). A–D by A. Mailhos.