Xenophyllum amblydactylum (S.F.Blake) V.A.Funk, Novon 7(3): 238. 1997.

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

19. Xenophyllum amblydactylum (S.F.Blake) V.A.Funk, Novon 7(3): 238. 1997.

Werneria amblydactyla S.F.Blake, J. Washington Acad. Sci. 18: 490. 1928. Type. Peru. Junín: Andes, Peru, Alpamarca, [without date], Capt. Wilkes Expedition s.n. (holotype: US-00037297!; isotype: GH s.n.!).

Description.

Suffruticose plant, forming clumps of erect stems. Rhizomes 10-12 × ca. 0.5 cm, horizontal to oblique, glabrous. Stems 4-7 cm tall, rather branched, glabrous, usually with leaves restricted to the upper part. Leaves subimbricate, extending into a sheath-like base that bears evanescent arachnoid trichomes; leaf laminas 4.3-10 × 1.3-1.4 mm, linear, barely broadened at the apex, 3-notched at the apex, entire, usually with some minute cilia near the base, flat to obtusely triangular in cross section, with evanescent arachnoid trichomes above, 1-nerved above (barely visible), 1-nerved beneath, somewhat fleshy, matte; leaf lobes 0.8-1.4 × 0.6-1 mm, obtuse. Capitula radiate, erect, sessile. Involucres 8.8-9.8 × 5.5-7 mm, cupuliform; involucral bracts 10 to 13, 4.9-5.4 × 1.2-1.8 mm, acute at the apex, greenish. Ray florets ca. 11; corollas 9-10.2 × ca. 1.2 mm, 4-veined, subentire to 2-toothed at the apex, conspicuously surpassing the involucre, white. Disc florets ca. 22; corollas 5.4-6 mm long, yellowish; style branches truncate with a crown of sweeping trichomes or slightly penicillate, yellowish. Achenes cylindrical, glabrous (immature); pappus ca. 5.6 mm long, barbellate, whitish. Chromosome number unknown.

Iconography.

Blake (1928: 496, fig. 1B, C sub Werneria amblydactyla ).

Distribution and habitat.

Endemic to Peru ( Junín, Lima). It grows in rocky outcrops of the puna ecoregion, at elevations of ca. 4600 m (Fig. 24 ).

Phenology.

Collected in flower in May.

Etymology.

The epithet amblydactylum means having blunt fingers ( “ambly-”: blunt, obtuse; “dactyl-”: finger). It refers to the leaf apex lobes of this species.

Notes.

Xenophyllum amblydactylum forms clumps of erect stems 4-7 cm tall that bear linear, 4.3-10 mm long leaves. The leaf apex is 3-notched and the lobes are small (0.8-1.4 × 0.6-1 mm) and connivent. The leaf lamina has arachnoid trichomes on the adaxial surface that are quicky evanescent. The involucre is 8.8-9.8 mm long and it is composed of 10 to 13 involucral bracts. The capitula are radiate and display ca. 11 ray florets with white corollas.

This is a poorly known and collected species. Aside from the type material, we only studied one collection from southeastern Lima Department ( Beltrán 4174, USM) and a specimen that was bought as medicinal in a farmers market in the city of Lima ( Yarupaitán 1499b, USM). Further collections are required in order to improve the understanding of its variability and properly describe the achenes.

It might be confused with X. dactylophyllum because their distribution areas overlap. However, several characters let anyone discriminate them from one another, i.e., leaf apex (3-notched in X. amblydactylum vs. at least 9-divided in X. dactylophyllum ), leaf lobe length (0.8-1.4 mm in X. amblydactylum vs. primary division 2-3 mm in X. dactylophyllum ), involucre length (8.8-9.8 mm in X. amblydactylum vs. 10.8-12.8 mm in X. dactylophyllum ), ray floret number (ca. 11 in X. amblydactylum vs. 17 to 22 in X. dactylophyllum ).

Additional specimens examined.

Peru. Lima: Yauyos, Laraos, Carhuanisho, 12°25'S, 75°36'W, 12 May 2001, H. Beltrán 4174 (USM); [without locality, bought as medicinal in the farmers market in ave. Aviación, La Victoria, Lima, 29 Oct 1994], G. Yarupaitán 1499b (USM).

Figures

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