Duseniella Schumann (1902: 475)

Ferreira, Paola De Lima, Antonelli, Alexandre & Groppo, Milton, 2021, Touch me carefully: a step towards understanding morphological diversity in the South American spiny sunflowers (Compositae, Barnadesioideae), Phytotaxa 518 (2), pp. 109-142 : 132

7. Duseniella Schumann (1902: 475)

Type: — Duseniella patagonica (O.Hoffm.) K.Schum.

Annual herbs, up to 10 cm tall, unarmed. Stems erect, much-branched, lenticelate, cylindrical or flat, scales imbricated at base, sparsely sericeous. Leaves opposite at base, alternate in the upper parts, sessile, persistent, blade linear, succulent, lustrous, adaxially glabrous or sparsely sericeous, adaxially sericeous, leaf margin flat, ciliate, apex mucronate; venation actinodromous, with 3 basal nerves, not evident and immersed in the mesophyll. Capitulescence terminal, monocephalous. Capitula heterogamous, disciform, 9–41-flowered, sessile, surrounded by subinvolucral bracts, involucre campanulate, 4–5-seriate, phyllaries scarious, erect, glabrous, ovate–oblong grading to linear, apex spiny, margin flat, ciliate. Receptacle convex, glabrous. Flowers heteromorphic. Ray flowers 4–16, pistillate, corolla tubular (5+0), 5-lobed, yellow, villous at apex. Style cylindrical, yellow. Disc flowers 5–25, bisexual, corolla tubular (5+0), 5-lobed, externally sericeous at base of corolla and apical lobes, internally sericeous at tube margin petals. Anthers 5, apical appendage lanceolate or obtuse, basal appendage acute, caudate, calcarate, inserted between the base and the throat, filaments free, glabrous. Style cylindrical, yellow. Cypsela cylindrical to turbinate, densely villous. Pappus scaly lanceolate, overlapped, shorter than the corolla tube, sericeous, ciliate. Pollen without intercolpal depression, microechinate (Suessy & Urtubey 2007). Chromosome number 2n = 54 (Baeza et al. 2019).

Fig. 7c–d ; 10e .

Distribution and habitat: — Duseniella is monotypic, represented only by D. patagonica , which is endemic to xeric areas in Argentinean Patagonia and Monte vegetation up to an altitude of 1,500 m. It occurs in semi-desert and steppe vegetation in Patagonia.

Notes: — Duseniella is a morphologically distinctive genus in the subfamily Barnadesioideae , being the only genus of annual herbs with unarmed branches, scucculent leaves, and disciform capitula with pappus scales overlapped and ciliate. Because of its distinctive morphology, Cabrera (1959, 1961) did not recognize the genus as a member of the subtribe Barnadesiinae (tribe Mutiseae ); instead, he placed Duseniella in the subtribe Gochnatiinae ( Cabrera 1977) . Phylogenetically, Duseniella is recovered in a clade with Doniophyton and Chuquiraga , but its relationship to these two genera is still unclear (see discussion above under Doniophyton ). A phylogenomic study including a large number of taxa from this clade could provide better insights into the evolution of this group.

Iconography: —Flora del Conosur available at http://www.darwin.edu.ar/Proyectos/FloraArgentina/ DetalleEspecie.asp?forma=&variedad=&subespecie=&especie=patagonica&genero= Duseniella &espcod=16513

Accepted species:—7.1 Duseniella patagonica (O. Hoffm.) K. Schum.

Selected specimens examined: — ARGENTINA. Chubut: Escalante, Pico Salamanca, 21 January 1965, E. De Marco de Kreibohm 223 (SI). Escalante , Comodoro Rivadavia , punta Bargia , 08 February 1903, M.S. Pennington 128 (SI). Ruta 20, 20 km al este de Sarmiento, 45°38’ 33.4”S, 68°57’01.0’‘W, 14 January 2002, J.M. Bonifacino 0437 (US) . Neuquén: Picún Leufú, 08 November 1972, E.M. Zardini 142 (MBM). Río Negro : Aguada Cecilio , 20 November 1980, Z.A. Manuel s.n. (SI). General Roca and vicinity, 250–360 m, 16 November 1914, W. Fischer 173 (MO). Camino de Cinco Saltos a Lago Pellegrini, E.M. Zardini 149 (MBM). General Roca , Labio S del Valle , frente a General Roca , 15 km, 16 February 1944, E.G. Nicora 4061 (SI). Santa Cruz : La Angostura , 300m, 13 January 1930, A. Donat 238 (MO). Corpen Aike , Laguna Grande hacia Gregores , 49°34’S, 70°14’W, 24 January 1967, O. Boelcke 12772 (SI). Deseado, 35 km de Jaramillo caminho al bosque petrificado, 10 January 1967, O. Boelcke 12169 (SI) .

Figures

FIGURE 7. Doniophyton and Duseniella. A–B: Doniophyton. C–D: Duseniella. A: Doniophyton anomalum. B: Doniophyton weddellii. C–D: Duseniella patagonica. Photos by Darwinion Institute.

FIGURE 10. Geographical distribution for the genera of Barnadesioideae. A: Dasyphyllum. B: Chuquiraga. C: Barnadesia (red dots) and Huarpea (blue triangle). D: Doniophyton (blue triangles); E: Archidasyphyllum (blue triangles); Fulcaldea (blue triangles)—these words (triagle) in plural (triangles).