Xenophyllum sotarense (Hieron.) 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

3. Xenophyllum sotarense (Hieron.) V.A.Funk, Novon 7(3): 240. 1997.

Werneria sotarensis Hieron., Bot. Jahrb. Syst. 21(3): 363. 1895 [ “soratensis”]. Type. Colombia. Cauca: Popayán al Sotará, cúspide del Sotará, 4400 m, Feb 1869, A. Stübel 339b (lectotype: MA-246367 (fragment!), designated by Funk (1997a: 240)). Epitype, designated here: Colombia. Cauca: Popayán, volcán Sotará, cima del volcán, 2°06 ’31’’ N, 76°35 ’31’’ W, 4440 m, 30 Nov 2017, J. Calvo, T. Buira & C. Velasco 7640 (MA-01-00928840!; isoepitype: CAUP s.n.!).

Werneria leucobryoides S.F.Blake, J. Washington Acad. Sci. 18: 494. 1928. Type. Ecuador. Napo: in m. Quilindaña ad nives perpetuas, Dec 1897, E. Festa s.n. (holotype: NY s.n.!; isotypes: G-00305674 (digital image!), P-02088568 (digital image!), Q-001222!, QPLS s.n.!, US-00037321 (fragment!)).

Description.

Suffruticose plant, forming dense mats or hummocks, with rhizome-like stems up to 5 cm long covered with sparse pilose indumentum and old leaves, rather erect, simple or branched from the base. Stems 1-1.5 cm tall (aerial part), sparsely pilose. Leaves densely stellate-imbricate, extending into a sheath-like base that bears scattered multicellular trichomes; leaf laminas 4-5 × 1-1.2 mm, linear, aristate at the apex (arista up to 0.5 mm long that falls as the leaves age), entire, thinly hyaline (in dried specimens), elliptical in cross section, glabrous, unconspicuously nerved above, 1-nerved beneath (barely visible), fleshy, drying coriaceous, matte, finely papillose. Capitula radiate, erect, sessile to subsessile. Involucres 4.9-5 × 4.8-5 mm, cupuliform; involucral bracts 12 to 13, 3.2-4 × 1.2-1.3 mm, obtuse at the apex, greenish. Ray florets ca. 13; corollas 6.3-6.5 × 0.8-1.2 mm, 2 to 4-veined, subentire to 2-toothed at the apex, conspicuously surpassing the involucre, white. Disc florets 14 to 15; corollas 3.3-4 mm long, whitish, usually purple-tipped; style branches truncate with a crown of sweeping trichomes, purplish. Achenes ca. 2.2 × 0.5 mm, cylindrical, 7 to 8-ribbed, glabrous; pappus 4.8-6.2 mm long, barbellate, whitish. Chromosome number unknown. Fig. 2B .

Additional iconography.

Blake (1928: 496, fig. 1Q-S sub Werneria leucobryoides ).

Distribution and habitat.

Southern Colombia to central Ecuador. Colombia (border Cauca/Huila), Ecuador (Chimborazo, Morona-Santiago, Napo, Tungurahua). It grows in rocky outcrops and scree slopes around the upper limit of vegetation of the superparamo ecoregion, between elevations of 4125-4800 m (Fig. 9 ).

Phenology.

Flowering from July to December.

Etymology.

The epithet sotarense refers to the Sotará Volcano, the locus classicus of this species. It is located in southern Colombia on the border between the departments of Cauca and Huila.

Notes.

Xenophyllum sotarense is characterized by its linear, 4-5 mm long, densely stellate-imbricate leaves, which are typically aristate at the apex. The arista measures up to 0.5 mm long and falls as the leaf ages. The sheath-like base bears scattered multicellular trichomes.

It is morphologically close to X. humile , especially to those small and compact plants with leaf laminas barely spreading from the sheath-like bases (see comments under it). To avoid misidentifications the following characters should be carefully studied: leaf apex (aristate or clearly acute when the arista falls in X. sotarense vs. obtuse to truncate in X. humile ) and stem indumentum (sparsely pilose in X. sotarense vs. lanate in X. humile ). Xenophyllum sotarense also shows morphological affinities with X. roseum . The involucre length (4.9-5 mm in X. sotarense vs. 10-12 mm in X. roseum ), the ray corolla length and color (6.3-6.5 mm, white in X. sotarense vs. 11.8-19 mm, pink in X. roseum ), and the achene indumentum (glabrous in X. sotarense vs. white-villous in X. roseum ) are useful characters for differentiating them.

The lectotype of Werneria sotarensis Hieron. at MA consists in a single sterile fragment barely informative and no isolectotypes appear to be extant; the duplicate at B was destroyed in 1943 (F0BN015821). For that reason, an epitype collected in the locus classicus has been designated. It is noteworthy that the plants from this locality are restricted on the volcano summit and co-occur with X. humile , a species much more abundant in the area that was also found at lower elevations.

The isotypes of Werneria leucobryoides S.F.Blake located at the Ecuadorian herbaria Q and QPLS show that the collector of this material was the Italian naturalist Enrico Festa instead of Luis Sodiro as the protologue indicates. This correction has been adopted since these specimens are the only ones that bear a label handwritten by Sodiro. It is feasible to think that the collector information was corrected on the specimens belonging to Sodiro’s personal herbarium but omitted on the duplicates to be distributed.

Additional specimens examined.

Ecuador. Chimborazo: El Altar, N side of the volcano, on the ridge below the Canoningo peak, 1°41'S, 78°24'W, 19 Aug 1995, P. Sklenář & V. Kostečková 90-5 (QCNE); Morona-Santiago: cerros Yuibug-Pailacajas, E side of the mountain ridge, 1°45'S, 78°27'W, 31 Jul 1997, P. Sklenář & V. Sklenářová 2941 (QCA, US); cerros Yuibug-Pailacajas, E side of the mountain ridge, 1°45'S, 78°27'W, 31 Jul 1997, P. Sklenář & V. Sklenářová 3022 (QCA); Napo: cerro Antisana, NW of north peak of Antisana, 0°27'S, 78°9'W, 28 Jul 1960, P.J. Grubb et al. 630 (K, NY); NE side of volcán Antisana, 0°27'S, 78°8'W, 17 Aug 1997, P. Sklenář & V. Sklenářová 3414 (QCA, US); NE side of volcán Antisana, 0°27'S, 78°8'W, 17 Aug 1997, P. Sklenář & V. Sklenářová 3418 (QCA); NE side of volcán Antisana, 0°27'S, 78°8'W, 17 Aug 1997, P. Sklenář & V. Sklenářová 3424 (QCA); volcán Antisana, NE side of the volcano, 0°27'S, 78°8'W, 21 Sep 2017, P. Sklenář 14116 (QCA); in pascuis summis m. Quilindaña, 0°47'S, 78°19'W, [without date], L. Sodiro s.n. (QPLS); Tungurahua: Santiago de Píllaro, P.N. Llanganates, SW ridge of cerro Hermoso, 1°13'S, 78°17'W, 14 Nov 1999, D. Neill et al. 12104 (QCNE); Santiago de Píllaro, P.N. Llanganates, SW ridge of cerro Hermoso, 1°13'S, 78°17'W, 14 Nov 1999, D. Neill et al. 12167 (QCNE); P.N. Llanganatis, slope on the W side of cerro Hermoso, 1°13'S, 78°17'W, 3 Dec 2010, P. Sklenář 13132 (QCA); cerro Hermoso, SW ridge of the mountain, 1°14'S, 78°18'W, 6 Sep 1997, P. Sklenář & V. Sklenářová 3741 (US).

Figures

Figure 2. Main habit types in Xenophyllum A, B species forming dense mats or hummocks C, D species forming clumps of somewhat distantly spaced stems A X. humile (Ecuador, Pichincha, pr. Papallacta) B X. sotarense (Colombia, Cauca, Sotara Volcano) C X. juniperinum (Chile, Antofagasta, Aucanquilcha Volcano) D X. digitatum (Bolivia, Potosi, cordillera Kari Kari). Pictures by Joel Calvo.

Figure 9. Distribution map of Xenophyllum sotarense (left hand, closed triangle), X. roseum (left hand, open circle), and X. funkianum (right hand).