Xenophyllum decorum (S.F.Blake) V.A.Funk, Novon 7(3): 239. 1997.

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

18. Xenophyllum decorum (S.F.Blake) V.A.Funk, Novon 7(3): 239. 1997.

Werneria decora S.F.Blake, J. Washington Acad. Sci. 18: 491. 1928. Type. Peru. Lima: Casapalca, 4725 m, 21 May 1922, J.F. Macbride & W. Featherstone 849 (holotype: F-517377!; isotypes: G-00237250 (fragment, digital image!), GH s.n.!, S-R-6523 (digital image!), US-00037303!).

Description.

Suffruticose plant, forming clumps of erect stems. Rhizomes 4-10 × 0.4-0.5 cm, horizontal to oblique, glabrous. Stems 11-19 cm tall, usually branched, glabrous, usually with leaves restricted to the upper part. Leaves imbricate, extending into a glabrous sheath-like base; leaf laminas 7.2-16 × 2.2-3.7 mm, linear-oblong, slightly broadened towards the apex, 3-notched at the apex, with the lateral lobes wider than central one, entire and shortly ciliate (cilia ca. 0.3 mm long), flat to slightly curved forwards in cross section, glabrous, 1-nerved above (barely visible), 1-nerved beneath, somewhat fleshy, matte; leaf lobes 0.6-1.5 × 1-1.6 mm (central one significantly smaller), rounded to subtruncate. Capitula radiate, erect, sessile. Involucres 10-12.6 × 8-10 mm, cupuliform; involucral bracts 13 to 14, 5.2-8 × 2-2.9 mm, acute to obtuse at the apex, greenish. Ray florets 20 to 21; corollas 10.4-11.9 × ca. 1.5 mm, 3-veined, subentire to 2-toothed at the apex, conspicuously surpassing the involucre, white. Disc florets 37 to 58; corollas 6-7 mm long, yellow; style branches truncate with a crown of sweeping trichomes or slightly penicillate, purplish. Achenes 4.8-5.4 × 1-1.2 mm, cylindrical, 7 to 8-ribbed, glabrous; pappus 8.7-9.8 mm long, barbellate, whitish. Chromosome number unknown.

Iconography.

Blake (1928: 496, fig. 1D, E sub Werneria decora ); Beltrán (2016: 359, fig. 3C, as photo).

Distribution and habitat.

Endemic to Peru (Ancash, Ayacucho, Huancavelica, Huánuco [expected], Junín, Lima). It grows in rocky outcrops, scree slopes, and on cryoturbated soils of the subhumid and humid puna ecoregions, between elevations of 3850-5000 m (Fig. 24 ).

Phenology.

Flowering from February to September.

Etymology.

The adjective decorus -a -um means handsome, elegant, decorous. Indeed, Blake (1928) pointed out in the protologue that it is "an attractive and very distinct species".

Notes.

This is a distinctive species due to the shortly ciliate leaf margin and the 3-notched leaf apex (the lateral lobes being conspicuously larger than the central one). The leaf lamina is glabrous, linear-oblong, slightly broadened towards the apex, flat in cross section but tending to be curved forwards. It has 13 to 14 involucral bracts, 20 to 21 ray florets with white corollas, 37 to 58 disc florets, and glabrous achenes.

Xenophyllum decorum has the leaf apex somewhat similar to that of X. incisum , however, their distribution areas are geographically very distant. In addition, these species differ in the leaf length (7.2-16 mm in X. decorum vs. 3.2-7.3 in X. incisum ), leaf margin (shortly ciliate in X. decorum vs. not ciliate in X. incisum ), number of involucral bracts (13 to 14 in X. decorum vs. 8 to 9 in X. incisum ), number of ray florets (20 to 21 in X. decorum vs. 8 to 13 in X. incisum ), and length of ray corollas (10.4-11.9 mm in X. decorum vs. 6.2-8.9 mm in X. incisum ).

It has to be noted that we had problems in identifying Beltrán 7987 (USM). This specimen exhibits the characteristic flat and ciliate leaves of X. decorum but has the leaf apex strongly divided (ca. 2.5 mm deep) with each lobe entire or divided once again. It might be treated as an intermediate form between X. decorum and X. dactylophyllum or X. digitatum since these species co-occur in the region where Beltrán’s specimen was collected.

Additional specimens examined.

Peru. Ancash: Huari, San Marcos, altura del km 111-112 de la carretera al campamento minero Antamina, 9°36'S, 77°1'W, 26 Mar 2004, A. Cano et al. 14168 (USM); Pallasca, Pampas, cordillera Pelagatos, 8°12'S, 77°46'W, 18 Apr 2011, A. Cano et al. 20203 (USM); collado encima río Pumapampa, 18 Mar 1983, O. Tovar et al. 9710 (USM); Ayacucho: Cangayllo-Huaytará, Paras-Pilpichaca, alrededor del abra Apacheta, 13°17'S, 74°42'W, 23 Aug 2014, P. Gonzáles et al. 3329 (USM); Huancavelica: Huaytará, alrededores de abra Apacheta, 13°18'S, 74°41'W, 3 Sep 2013, P. Gonzáles et al. 2783 (USM); Junín: Anticona pass, ca. 140 km E of Lima on Hwy. to La Oroya, 11°35'S, 76°11'W, 16 Dec 1978, M. Dillon & B.L. Turner 1308 (USM); Lima-La Oroya highway, cumbre at top of divide, above Morococha, 11°36'S, 76°8'W, 29 Jun 1982, A. Gentry & R. Tredwell 37301 (USM); Ticlio, 11°35'S, 76°11'W, 11 Jul 1982, B. Maass 575 (USM); Yauli, Anticona arriba, 11°35'S, 76°10'W, 24 Mar 1979, O. Tovar, S. Rivas & Sáenz 7806 (USM); Anticona, abajo entre Casapalca y Oroya, 11°35'S, 76°11'W, 26 Jun 1954, O. Tovar & L. Constance 9194 (USM-29378 [mixed with X. ciliolatum and digitatum ]); Lima: Huarochirí, paso de Anticona, 11°35'S, 76°11'W, 1 May 1999, H. Beltrán & E. Li 3306 (USM); Yauyos, Laraos, pampas de Quiray cerca a la laguna de Huinso, 12°23'S, 75°48'W, 4 Feb 2000, H. Beltrán 3418 (USM); Yauyos, Laraos, estancia de Quiray, 6 horas de camino al pueblo, 12°24'S, 75°45'W, 11 May 2001, H. Beltrán 4059 (USM); Yauyos, Laraos, Viscollo, 12°25'S, 75°36'W, 12 May 2001, H. Beltrán 4188 (USM); Huarochirí, desvío de carretera central hacia Chinchan y Marcapomacocha, 11°34'S, 76°15'W, 23 Sep 2014, H. Beltrán & W. Aparco 7740 (USM); Huarochirí, Chicla, abra Anticona (Ticlio), 11°35'S, 76°11'W, 29 Apr 2017, H. Beltrán, S. Castillo & M. Arakaki 7988 (USM); Yauyos, Tomas, abra Chaucha, 12°14'S, 75°38'W, 10 Aug 2017, H. Beltrán 8469 (USM); Huarochirí, Ticlio, 11°35'S, 76°11'W, 8 Aug 1982, K. Biegman s.n. (USM); Yauyos, Laraos, camino a Mina, 12°25'S, 75°41'W, 14 Apr 2012, A. Cano & H. Trinidad 20646 (USM); Huarochirí, San Damián, Chanape, 11°55'S, 76°10'W, 7 Jul 2013, P. Gonzáles & B. Brito 2655 (USM); Huarochirí, Ticlio, canyon of the río Rimac, on the carretera central, 11°35'S, 76°11'W, 19 Aug 1957, P.C. Hutchison 1212 (CONC, F, GH, LE, NY, UC, US [all specimens mixed with X. digitatum ]); Anticona, 11°35'S, 76°15'W, 5 Aug 2012, E. Linares & A. Galán 3101 (USM); Canta, La Viuda (km 165 carretera Lima-cerro de Pasco), 11°21'S, 76°26'W, 7 Aug 1964, I. Meza 227 (USM); Canta, Cullhuay, laderas de la laguna de Chuchún, 11°22'S, 76°26'W, 17 Aug 1996, G. Vilcapoma 4461 (USM).

Figures

Figure 24. Distribution map of Xenophyllum decorum (left hand, closed triangle), X. amblydactylum (left hand, open circle), and X. dactylophyllum (right hand).