Praxelis missionum (Malme) King & Robinson (1970b: 195)

Christ, Anderson Luiz & Ritter, Mara Rejane, 2019, A taxonomic study of Praxelinae (Asteraceae-Eupatorieae) in Rio Grande do Sul, Brazil, Phytotaxa 393 (2), pp. 141-197 : 148-149

1.2. Praxelis missionum (Malme) King & Robinson (1970b: 195) .

Eupatorium missionum Malme (1931: 35) . Lectotype (designated by Freire & Ariza Espinar 2014: 405):— ARGENTINA . Misiones: Posadas, 12 November 1907, E.L. Ekman 1119 (S! [S-R-8992], isolectotype S! [ S10-20101 ]).

= Eupatorium kleinioides var. hecatanthum Baker (1876: 343) . Praxelis hecatantha Schultz-Bipontinus ex Baker (1876: 343) nom. nud. pro syn. Lectotype (designated by Christ & Ritter 2018: 113):— BRAZIL. s.l., s.d., F. Sellow 3652 (K! [K000486862], isolectotypes P! [P02476868], B, probably lost, Field Museum Berlin Negative 16283!). ( Fig. 2E–H , 3D–E ).

Herbs or rarely subshrubs, up to 35 cm tall, erect to decumbent, branched from base or only in capitulescence; stems hirsute. Leaves 1.3–5.6 × 0.2–1.3 cm, sessile; leaf blade lanceolate to rarely oblanceolate, papyraceous to chartaceous, apex acute to obtuse, rarely acuminate, base attenuate, margins sparsely serrate to serrate, rarely entire, adaxial surface strigose to hirsute, rarely glabrous, abaxial surface hirsute. Primary capitulescences umbellate or capitula solitary, axis bracteate or ebracteate, bracts 1–3.2 × 0.2–0.9 cm, sometimes with margins entire. Capitula pedunculate to long pedunculate, peduncles 1.6–14 cm long, hirsute; involucres 6.3–7.9 × 4.5–9.4 mm, involucral bracts 20–25, 3-seriate, outer 3.3–5.3 × 0.7–2 mm, apex citrine, hirsute, abaxial surface citrine, 5–7-veined, hirsute, inner spatulate, 5.7–6.7 × 0.9–1.7 mm, apex rounded to truncate, rarely acuminate, citrine, glabrous to puberulous, abaxial surface citrine, 5–7- veined. Florets 60–95, corollas 3.6–5 × 0.5–0.7 mm, lilac or white, lobes eglandular. Cypselas obconical, 1.8–2.5 × 0.5–0.8 mm, 3–4-ribbed, ribs and sinuses setuliferous, pappus setae ca. 13–22, white to ferruginous, 3–4.6 mm long.

Distribution: — Argentina , Brazil and Paraguay ( Cabrera 1996). In Brazil, it occurs in the Southern region (Paraná, Rio Grande do Sul and Santa Catarina). In Rio Grande do Sul, it occurs in the physiographic regions of Alto Uruguai and Missões ( Fig. 4 , circles).

Habitat: —Grasslands of biomes Atlantic Forest and Pampa, usually in shallow soils with rocky outcrops.

Phenology: —Flowers from the end of spring to the middle of summer, with a flowering peak between the months of November and February.

Etymology: —The specific epithet is a reference to the Argentine province of Misiones, where the type specimen was collected.

Comments: — Praxelis missionum is a common species in rocky outcrops and grasslands with shallow soils in the northwest of Rio Grande do Sul, where large populations of the plant can be found. The species is easily recognizable by its short habit, by the usually solitary capitula with long peduncles and by the dense hirsute indumentum of leaves, stems and peduncles. In general, specimens bearing white flowers also show an even slender habit and shorter peduncles than the ones bearing lilac flowers. However, this pattern is not without exceptions, being the reason why we decided not to describe a new variety and to recognize all of the specimens as a single taxonomic entity.

Praxelis kleinioides is very similar to P. missionum , the main differences between them are fewer florets in the former’s capitula and its general habit and branches of the capitulescence. Matzenbacher (1979) has pointed to the occurrence of P. kleinioides in Rio Grande do Sul, but we found that all the specimens analyzed by this author were, in fact, specimens of P. missionum with a somewhat more robust and more branched habit. We agree with Abreu (2015), who indicated that, in Southern Brazil, P. kleinioides occurs only in the state of Paraná.

Following Turland et al. (2018), Art. 23.5, the correct name of this species is P. missionum , and not P. missiona , as it has been traditionally cited. This is because the specific epithet is a genitive plural noun, and thus should retain its own gender and termination, despite the genus ( Praxelis ) being a feminine noun.

Specimens examined: — BRAZIL: Rio Grande do Sul: Caibaté: Caaró, 24 November 1952, Rambo, B. s.n. ( PACA). Cerro Largo : s.l., 1946, Augusto , I. s.n. ( PACA). Derrubadas : Parque Estadual do Turvo , 20 December 1982, Matzenbacher, N. I. s.n. ( ICN53450 ) ; January 1990, Sobral, M. et al. 6104 ( ICN) ; 02 November 1993, Matzenbacher, N. I. s.n. ( ICN103648 ) ; 03 December 2016, Christ, A. L. 342a, 342b ( ICN). Giruá: Granja Sodal , 28 April 1963, Hagelund, K. 667 ( ICN) ; November 1963, Hagelund, K. 1343 ( ICN) ; 10 February 1965, Hagelund, K. 3216 ( ICN) ; 13 February 1965, Hagelund, K. 3353 ( ICN) ; 01 November 1965, Hagelund, K. 3924 ( ICN). Itacurubi: s.l., 08 December 2012, Carneiro, C. R. 95 ( ICN). Planalto: RS-324, 26 September 2005, Schneider, A. A. 1136 ( ICN). Porto Xavier: s.l., 07 October 1972, Hagelund, K. 6390 ( ICN) ; 17 February 1973, Hagelund, K. 6803 ( ICN). Santiago: 94 Km de São Borja , 20 December 1972, Lindeman, J. C., Pott, A. et al. s.n. ( ICN) ; 50 Km da entrada para São Borja , 10 September 1995, Mondin, C. 1052 ( ICN). Santo Ângelo: Granja Piratini, 01 December 1974, Hagelund, K. 8459 ( ICN). Santo Antônio das Missões: s.l., 06 November 2007, Schneider, A. A. 1562 ( ICN). Unistalda: s.l., 08 September 2012, Valduga, E. 431 ( HUCS) .

Figures

FIGURE 2A–D: Praxelis clematidea. A. Fertile branch. B. Capitulum. C. Involucral bracts. D. Floret. E–H: Praxelis missionum. E. Fertile specimen. F. Capitulum. G. Involucral bracts. H. Floret.

FIGURE 3A–C: Praxelis clematidea. A. Fertile branch. B. Leaves. C. Primary capitulescence. D–E: Praxelis missionum. D. Fertile specimens. E. Capitulum. Credits: Sérgio Bordignon (A–B), Anderson Christ (C–E).

FIGURE 4: Distribution of P. clematidea (triangles) and P. missionum (circles) in Rio Grande do Sul.