Stenocephalum hystrix (Chodat) Robinson (1987: 583)

Dematteis, Massimiliano & Angulo, María Betiana, 2020, Taxonomic revision of the genus Stenocephalum (Vernonieae, Asteraceae), Phytotaxa 438 (1), pp. 15-36 : 24-26

3. Stenocephalum hystrix (Chodat) Robinson (1987: 583) . Vernonia hystrix Chodat (1902: 298) .

Type:— PARAGUAY. Canindeyú: In altoplanitie et decliviis Sierra Maracayú. In campo Ñandurocay. Suffrutex 0,5-1, petala violacea. October 1898 /1899. E. Hassler 4927 (holotype G 00093666!, isotypes BM 000092954!, G 00093665!, G 00093664!, GH 00013703!, K 000485911!, NY 00274847!, P 00682755!, UC 944708!, W!).

= Vernonia revoluta Barroso (1954: 8) , syn. nov.

Type:— BRAZIL. Mato Grosso do Sul, Campo Grande, 1949, Guerra 80 (holotype RB 00287600!).

Erect suffrutex 50–90 cm tall. Stems single, branched only at base, striate, glabrescent, densely leafy, 3–4 mm in diameter in lower portion, internodes 1–5 mm long. Leaves sessile, ascending, dense, frequently verticillate to subopposite, 7–9 cm long, 0.2–0.5(–0.8) cm wide. Leaf blades narrowly linear to linear-lanceolate, margin entire, revolute, acute at apex, basally rounded, above glabrous, lustrous, glandular-dotted, below densely white-tomentose, the middle vein being only visible. Capitula numerous, disposed in groups of 3–6 along stems in a spiciform capitulescence. Bracts of the inflorescence leafy, gradually shorter to the apex, sometimes reduced, disposed at the base of each head cluster. Involucre ovate-cylindrical, 7–9 mm high, 3.5–4.5 mm in diameter. Phyllaries densely imbricate, arranged in 4–5 series, ovate to ovate-lanceolate, apically apiculate, with a spine of ca. 2 mm long, glabrous, purple to brownish with the apex purple. Florets 6–7, violet. Corollas with glandular trichomes at lobes apices. Anther apical appendages lanceolate, 0.3–0.4 mm long. Style without basal node. Cypselas 3–3.4 mm long, pubescent, trichomes glandular, pericarp without crystals and idioblasts. Pappus grayish to white. Pollen grains oblate-spheroidal, 40–47 µm in diameter, colpus 40.80–47.65 µm long, spines 3.0–4.8 µm long.

Distribution and habitat: —This species grows on rocky open lands of southeastern Paraguay (Amambay, Canindeyú, Cordillera) and western Brazil (Mato Grosso do Sul).

Phenology: —Flowering and fruiting in the summer, from December to February.

Conservation status: —Following the criteria established by IUCN ( IUCN 2017), a provisional assessment of Vulnerable (VU: B2ab iii) is proposed for this taxon. Its area of occupancy (AOO) is less than 20000 km 2 and it is currently only known from no more than 10 locations. Only one of these locations is included in a protected area.

Notes: —Each heads cluster has a short pedicell with a leafy bract at the base. In the same node of the inflorescence 2–3 glomerules can be observed disposed at the same level of the stems, each with a leafy bract. This produces a verticillate general appearence of the capitulescence and upper leaves.

Additional specimens examined: — BRAZIL. Mato Grosso do Sul: alrededores de Campo Grande, camino a Sidrolandia, 10 February 1979, A. Krapovickas & C. L. Cristóbal 34511 ( CTES). PARAGUAY. Amambay: Fazenda El Buracon, 30 km O de Pedro Juan Caballero , 15 December 1964, G. Hatschbach & R. Callejas 47256 ( C, MBM, US) ; Pedro Juan Caballero (Ponta Porá), 15 December 1983, R. Callejas , G. Hatschbach , J. M. da Silva & C. Ramos 1942 ( G, K, RB, US) ; Sierra de Amambay, Estancia Estrella, 22º23’56”S- 55º59’50”W, 7 March 2002, A. Schinini , M. Dematteis , R. Duré & M. Quintana 36215 ( CTES, PY) ; Sierra de Amambay, pr. Estrella , January 1907 /1908, E. Hassler & T. Rojas 10071 ( BAF, BM, G, K, P, W). Canindeyú: Aquere-mí, en cerrado, November 1995, I. Basualdo 5948 ( FCQ) ; 25 km E de Igatimí, 5 December 1998, M. Dematteis & A. Schinini 852 ( CTES, G, MBM) ; Reserva Natural Mbaracayú, puesto Aguará-Ñú, 210 msm, 7 December 2003, M. E. Múlgura de Romero , C. Calviño, S. Martínez & N. O’Leary 3590 ( CTES, SI) ; unos 30 km al S de Capitan Bado, Ñunguazú Ybicui, 5 February 1982, J. Fernández Casas & J. Molero 6000 ( G). Cordillera: Caacupé , 4 January 1979, R. Matta 546 ( CTES) .