Xenophyllum pseudodigitatum (Rockh.) V.A.Funk, Novon 7(3): 240. 1997.

Calvo, Joel & Moreira-Munoz, Andres, 2020, Taxonomic revision of the Andean genus Xenophyllum (Compositae, Senecioneae), PhytoKeys 158, pp. 1-106 : 1

17. Xenophyllum pseudodigitatum (Rockh.) V.A.Funk, Novon 7(3): 240. 1997.

Werneria pseudodigitata Rockh., Bot. Jahrb. Syst. 70: 288. 1939. Type. Argentina. Salta: Umgebung des Nevado del Castillo, 3050-4570 m, 19/23 Mar 1873, P.G. Lorentz & G. Hieronymus 96 (lectotype: GOET s.n.!, designated by Funk (1997a: 240); isolectotypes: CORD-00005638 (digital image!), K s.n.!).

Werneria castillensis Hieron., nom. nud. in sched. ( Turland et al. 2018, ICN Art. 38.1).

Description.

Suffruticose plant, forming clumps of erect stems. Rhizomes 5-8 × 0.4-0.6 cm, horizontal to oblique, glabrous. Stems 5-12 cm tall, simple or branched, glabrous, usually with leaves restricted to the upper part. Leaves imbricate, extending into a glabrous sheath-like base; leaf laminas 6-9.6 × 2-3.8 mm, linear-spatulate (broadened upwards), 3-forked at the apex (incision depth 1/8-1/7 of the total length), entire, sometimes with some minute cilia in the lower half, flat to elliptic or almost terete upwards in cross section, glabrous, 1-nerved above (barely visible), 1-nerved beneath, fleshy, matte; leaf lobes 1.3-2.6 × 1-1.6 mm, acute to mucronate (rarely notched). Capitula radiate, erect, sessile. Involucres 7-8.4 × 5.2-8 mm, cupuliform; involucral bracts 10 to 11, 3.4-3.9 × 2-2.8 mm, obtuse at the apex, greenish. Ray florets 20 to 25; corollas 7.1-8.2 × 1-1.2 mm, 3 to 4-veined, subentire to 3-toothed at the apex, conspicuously surpassing the involucre, white. Disc florets 29 to 33; corollas 4.2-5.1 mm long, yellowish; style branches penicillate, purplish. Achenes 2.3-2.5 × 0.5-0.7 mm, cylindrical, 7 to 9-ribbed, glabrous; pappus 5.2-7.1 mm long, barbellate, whitish. Chromosome number unknown. Fig. 22 .

Additional iconography.

Cabrera (1978: 473, fig. 200A-F, sub Werneria pseudodigitata ); Funk (1997a: 237, fig. 1C); Freire and Ariza-Espinar (2014: 228, X. pseudodigitatum A-E).

Distribution and habitat.

Endemic to Argentina (Jujuy, Salta). It grows in rocky slopes on rather wet soils of the dry puna ecoregion, between elevations of 3700-5125 m (Fig. 23 ).

Phenology.

Flowering from January to May.

Etymology.

The epithet pseudodigitatum refers to the resemblance between this species and X. digitatum . It probably responds to the fact that both species have 3-forked leaves.

Notes.

Xenophyllum pseudodigitatum is characterized by its 3-forked leaves. The leaf lobes are 1.3-2.6 mm long, which represents 1/8-1/7 of the total leaf length, and they are acute to mucronate at the apex (rarely notched); on living plants, they are noticeably spread out. The involucre length ranges from 7 to 8.4 mm and has 10 to 11 involucral bracts. The radiate capitula are composed of 20 to 25 ray florets and 29 to 33 disc florets.

This is a narrow endemic species to northwestern Argentina that has erroneously been reported from northern Chile ( Ricardi and Marticorena 1966; Freire and Ariza-Espinar 2014; Moreira-Muñoz et al. 2016) and southern Peru ( Gonzáles et al. 2016). All these records are confusions with X. digitatum . In order to avoid further misidentifications, the following characters should be studied: leaf lobe length (1.3-2.6 mm in X. pseudodigitatum vs. 3.6-5.9 mm in X. digitatum ), involucre length (7-8.4 mm in X. pseudodigitatum vs. 12.1-16.7 mm in X. digitatum ), number of involucral bracts (10 to 11 in X. pseudodigitatum vs. 12 to 13 in X. digitatum ), ray corolla length (7.1-8.2 mm in X. pseudodigitatum vs. 9.2-14.1 mm in X. digitatum ), and number of disc florets (29 to 33 in X. pseudodigitatum vs. 49 to 63 in X. digitatum ). Their distribution areas do not overlap.

Additional specimens examined.

Argentina. Jujuy: Humahuaca, mina Aguilar, 23°12'S, 65°43'W, 11 Jan 1968, A.L. Cabrera et al. 19009 (SI); mina Aguilar, abra Aguilar, 23°9'S, 65°42'W, 19 Feb 1969, A.L. Cabrera, J. Crisci & R. Kiesling 19843 (C); Volcán, abra del Córdoba, 23°53'S, 65°34'W, Feb 1922, L. Castillón 1761 (LIL); Estación Volcán, 23°53'S, 65°34'W, Feb 1920, L. Castillón 7140 (A, F); El Aguilar, oberhalb, 5° E. Hochandine Polsterflur, 23°11'S, 65°42'W, 1 Feb 1971, H. Ellenberg 4295 (US); Tilcara, subida a la abra de Remate, 23°32'S, 65°16'W, 15 Feb 1953, A. Fiebrig s.n. (LIL); near mina La Esperanza, just before entrance to town of El Aguilar, side rd. to mina La Esperanza, 23°10'S, 65°43'W, 9 Mar 1993, V.A. Funk & L. Katinas 11157 (US); rd. to mina La Esperanza, 23°10'S, 65°43'W, 9 Mar 1993, V.A. Funk & L. Katinas 11169 (US); Humahuaca, mina Aguilares, arriba de la mina, 23°11'S, 65°43'W, 29 Mar 1952, E. Petersen & J.P. Hjerting 159 (C, LIL); Humahuaca, subida al cerro Aguilar, 23°11'S, 65°43'W, 17 Jan 1953, H. Sleumer 3448 (LIL); Humahuaca, cerro Aguilar, cumbre, 23°11'S, 65°43'W, 17 Jan 1953, H. Sleumer 3452 (LIL); Tilcara, cumbre del cerro, 23°36'S, 65°28'W, 3 May 1927, S. Venturi 6254 (US).

Figures

Figure 22. Xenophyllum pseudodigitatum A habit B, C capitula at different stages of development D leaf E leaf apex variability F ray floret (frontward bristles removed) G ray floret (pappus removed) H disc floret (frontward bristles removed) I stamen J style. All details drawn from Ellenberg 4295 (US) except for B, C, F (drawn from Petersen & Hjerting 159, C). Illustration by Alice Tangerini.

Figure 23. Distribution map of Xenophyllum digitatum (left hand) and X. pseudodigitatum (right hand).