Chromolaena latisquamulosa (Hieronymus) King & Robinson (1970: 202)

Christ, Anderson Luiz, Nakajima, Jimi Naoki & Ritter, Mara Rejane, 2025, Towards a better understanding of the Chromolaena congesta complex (Asteraceae, Eupatorieae): updated synopsis with taxonomic novelties, Phytotaxa 689 (2), pp. 163-184 : 175-176

8. Chromolaena latisquamulosa (Hieronymus) King & Robinson (1970: 202) . Eupatorium rhinanthaceum var. latisquamulosum Hieronymus (1897: 759) .

Type:— BRAZIL. Paraná: Lago, 14 December 1904, P. Dusén 3227 (neotype: S-R-8995!, designated by Christ & Ritter (2018: 113)).

( Fig. 4G–I )

Distribution: —This species is restricted to Brazil (Paraná, Rio Grande do Sul, Santa Catarina and São Paulo states). Chromolaena latisquamulosa is typical of highland grasslands of the Mata Atlântica domain, usually near Araucaria Forests.

Flowering period: —Flowers from December to June, with a flowering peak from January to March.

Conservation status: —Near Threatened (NT). Chromolaena latisquamulosa ’s AOO places it closer to a Vulnerable (VU) categorization, but we refrained from classifying this species as such due to the existence of more than 10 known populations. However, C. latisquamulosa suffers a pressure from habitat loss as many grasslands in southern Brazil are currently being converted into pasture or agricultural lots, even in the Mata Atlântica highlands ( Külkamp et al. 2018). As this species is exclusive to these environments, the continued decline in habitat quality and quantity may place it in a category of risk soon. Nonetheless, C. latisquamulosa is protected by conservation units in many locations, such as by Parque Nacional de Aparados da Serra, Parque Estadual do Tainhas and Parque Nacional de São Joaquim, all in southern Brazil.

Comments: — Chromolaena latisquamulosa is one of the principal species of the complex in the highland grasslands of southern Brazil. This species can be recognized by the combination of decumbent habit ( Fig. 4G ); last internodes usually around 8–12 cm long.; stems usually strigose to puberulous; leaves orbicular to ovate ( Fig. 4H ), nearly always glabrous (rarely glabrescent) on the adaxial surface and glabrous to strigose on the abaxial surface; and common absence of glandular hairs in phyllaries ( Fig. 4I ), florets and cypselae (e.g. Fig 2A–B ). Christ et al. (2023a) has indicated the need to expand this species morphological concept to also include populations with glandular leaves and rarely villose to hirsute stems. These traits, however, are considered anomalous in C. latisquamulosa , as most populations follow the set of traits mentioned above.

Chromolaena latisquamulosa is morphologically similar to C. congesta , from which it differs mostly through the growing habit (erect in C. congesta ), shape and indument of the leaves (deltate, strigose on the adaxial surface and strigose to tomentose on the abaxial surface in C. congesta ), venation usually immersed on the abaxial surface of the leaves (vs. venation emergent in the abaxial surface of the leaves in C. congesta ) and absence of glandular hairs in the reproductive organs (vs. phyllaries, florets and cypselae glandular in C. congesta ).

Selected specimens: — BRAZIL. Paraná: Balsa Nova, São Luiz do Purunã , 12 December 1965, R. Reitz 17446 ( FLOR) ; Campo Largo , 09 October 1964, L. T. Dombrowski 522 ( RB) ; Castro, Estrada do Cerne , 09 January 1957, G. Hatschbach 602 ( PACA) ; Curitiba , 06 Dezember 1960, E. A. Moreira 150 ( RB) ; Palmas , REVIS dos Campos de Palmas, 26°30’46.71”S, 51°35’7.72”W, 06 June 2013, S. Campestrini 224 ( FLOR) ; Ponta Grossa, 13 January 1964, E. Pereira 8233 ( PEL). Rio Grande do Sul: Bom Jesus, Fazenda Caraúna , 02 February 1937, J. Dutra 1461 ( ICN) ; Cambará do Sul, Parque Nacional de Aparados da Serra , 29°09’36.6”S, 50°04’39.7”W, 29 April 2017, A. L. Christ 441 ( ICN) ; Jaquirana, Parque Estadual do Tainhas , 29°05’08.7”S, 50°22’02.3”W, 04 March 2018, A. L. Christ 502 ( ICN) ; São Francisco de Paula , 10 February 1979, K. Hagelund 12655 ( ICN) ; São José dos Ausentes , RS-020, 28°28’54.0”S, 49°53’33.7”W, 10 March 2019, A. L. Christ 618 ( ICN) ; Vacaria, Passo do Socorro, 26 December 1951, B. Rambo s.n. ( PACA 51431 ). Santa Catarina: Bom Jardim da Serra , Serra do Rio do Rastro , 28°24’42”S, 49°34’00”W, 27 February 2020, A. L. Christ 699 ( ICN) ; Lages , 10 January 1951, B. Rambo 49530 ( ICN) ; São José, Serra da Boa Vista , 02 March 1961, R. Reitz 10821 ( FLOR) ; Urubici, Campo dos Padres , 27°56’39”S, 49°20’47”W, 08 March 2006, A. Zanin 965 ( ICN). São Paulo: Campos do Jordão , 20 February 1937, P. Campos Porto 3139 ( RB) .

Figures

FIGURE 2. Representative cypselae of species of the C. congesta complex portraying morphological variation in diagnostic traits. A. glabrous cypsela (i.e. setae completely or nearly completely absent). B. setulliferous cypsela (i.e. setae visibly present on the ribs and/on between them). C. glandular cypsela (i.e. glandular hairs located at the tips of the arrowheads). Scale bars: 2 mm. Further details on the structure of the cypselae of this species complex are described in Queiroz et al. (2025).

FIGURE 4. A–C. Chromolaena gentianoides. A. Leaves. B. Branches and secondary capitulescence. C. Capitulum. D–F. Chromolaena hirsuta. D. Stem and leaves. E. Details of leaves. F. Capitulescence. G–I. Chromolaena latisquamulosa. G. Growing habit. H. Leaves. I. Capitulum. J–L. Chromolaena rhinanthacea. J. Leaves. K. Detail of stem. L. Capitulum. Scale bars of C, I and L = 2 mm; scale bar of K = 5 mm. Image credits:Anderson Christ (A–C, F–L), Rodrigo Dall’Agnol (D) and Sérgio Bordignon (E).