Xenophyllum funkianum J.Calvo, 2020

Calvo, Joel & Funk, Vicki A., 2020, Two new species of the Andean genus Xenophyllum (Senecioneae, Compositae), PhytoKeys 139, pp. 29-38 : 29

1. Xenophyllum funkianum J.Calvo sp. nov. Figs 1 , 2

Diagnosis.

Xenophyllum funkianum is well characterized by its creeping rhizome-like stems 20-35 cm long, the straight linear leaves prolonged into a sheath-like base that bears arachnoid trichomes, the dark-burgundy sessile involucres with 13-14 involucral bracts, the 12-13 white ray florets somewhat purplish beneath, and by having white-villous achenes.

Type.

Ecuador. Chimborazo: Mt. Chimborazo area, at the end of Polylepis road and beginning of hike to Polylepis forest, 1°31'50"S, 78°52'55"W, 4233 m, 20 Apr 2018, V.A. Funk & J.M. Bonifacino 14059 (holotype: US!; isotypes: MO!, QCA!).

Description.

Suffruticose plants, forming creeping lax mats, with rhizome-like stems 20-35 cm long, 0.3-0.5 cm in diam., covered by arachnoid indumentum and leaf-base remnants resembling paleae, horizontal, simple or branched from the base. Stems 2-3 cm long (aerial part), arachnoid. Leaves simple, alternate, imbricate, straight, prolonged into a sheath-like base that bears arachnoid trichomes; leaf laminas linear, 5.3-7.8 mm long, 0.8-0.9 mm wide, entire, rather acute, callous-tipped at the apex, elliptical in cross section, glabrous, unconspicuously nerved above, 1-nerved beneath (only conspicuous on the lower third), fleshy, shiny, papillose. Capitula radiate, solitary, terminal, erect, sessile. Involucres 9-11 mm long, 5-7 mm wide, cupuliform, with bracts fused at the base, glabrous; involucral bracts 13-14, 4.7-6.9 mm long, 1.0-1.7 mm wide at the base, acute at the apex, dark-burgundy; without supplementary bracts. Ray florets 12-13, corollas 8.9-11.6 mm long, 2.3-3.0 mm wide, 4-veined, subentire to 3-toothed at the apex, conspicuously surpassing the involucre, white, somewhat purplish beneath. Disc florets 20-23, corollas 5.0-5.6 mm long, 5-lobed, yellowish; style branches truncate with a crown of sweeping hairs, yellowish; anther bases obtuse; anther appendages two times longer than wide, ca. 0.4 × 0.2 mm. Achenes cylindrical, with white-villous trichomes (immature); pappus 3.9-6.2 mm long, barbellate, whitish. Chromosome number unknown.

Distribution and habitat.

Endemic to Ecuador (provinces of Bolívar and Chimborazo) (Fig. 3 ). It grows in exposed places and sandy soils of the dry superparamo, at elevations of 4100-4300 m.

Phenology.

Flowering from April to July.

Etymology.

The epithet honors the American botanist Vicki A. Funk (1947-2019), who greatly contributed to the understanding of the family Compositae worldwide.

Discussion.

Xenophyllym funkianum is morphologically close to X. rigidum (Kunth) V.A.Funk, a species distributed in central Ecuador which overlaps its distribution area. They can be easily differentiated by the leaf lamina size (5.3-7.8 × 0.8-0.9 mm in X. funkianum vs. 12.6-13.5 × 2.3-2.4 mm in X. rigidum ), involucre size (9-11 × 5-7 mm in X. funkianum vs. 11.5-12.8 × 7.2-11.3 mm in X. rigidum ), and number of disc florets (20-23 in X. funkianum vs. 38-41 in X. rigidum ). Moreover, X. rigidum is a larger plant and the capitula are completely enclosed among the leaves. Xenophyllym funkianum also shows morphological affinities with X. humile (Kunth) V.A.Funk; indeed, previous botanists confused the new species with it. They differ in the leaf shape (straight in X. funkianum vs. usually articulate in X. humile ), involucre length (9-11 mm in X. funkianum vs. 4.6-9.3 mm in X. humile ), and achene indumentum (white-villous in X. funkianum vs. glabrous in X. humile ). Their way of growing is also different; X. humile forms dense mats or hummocks, whereas X. funkianum is rather a creeping plant. Another similar species is X. roseum (Hieron.) V.A.Funk, a species known from the Ecuadorian provinces of Azuay and Cañar that does not overlap the distribution area with the new species. Any confusion is unlikely since X. roseum displays pink ray florets and the young leaves usually bear a quickly deciduous arista up to 0.5 mm.

The white-villous achene indumentum of X. funkianum is composed of twin filiform trichomes, with acute to subacute, asymmetrical, slightly forked apex (Fig. 2D ). This type of indumentum is also found in X. rigidum and X. roseum ; however, most species of the genus have glabrous achenes.

Additional specimens examined (paratypes).

Ecuador. Bolívar: road to Salinas, 1.8 km W of Guaranda-Ambato hwy., 1°25'S, 79°0'W, 25 Jun 1989, L.J. Dorr & I. Valdespino 6474 (QCA barcode 159734, QCNE-47994, US barcode 00622748); Chimborazo: Mt. Chimborazo area, side road ends and connects to trail that leads to the Polylepis forest, 1°32'S, 78°53'W, 20 Apr 2018, V.A. Funk & J.M. Bonifacino 14061 (US); W side of the Chimborazo volcano, arenal around loma Guagua Lozán, 1°27'S, 78°54'W, 3 Jul 1999, P. Sklenář 7528 (QCA barcode 161918, QCNE-159009, PRC n.v.).

Figures

Figure 1. Xenophyllum funkianum A habit B habit with capitula C stem apical part D detail of leaf apex E capitulum F ray floret and achene (frontward bristles removed) G disc floret without pappus and achene H stamen. All details drawn from Funk & Bonifacino 14059 (US). Illustration by Alice Tangerini.

Figure 2. Xenophyllum funkianum A capitulum B involucre and leaves C habit D apex of achene trichomes (20 x Standard 16 WL); material taken from Funk & Bonifacino 14059 (US).

Figure 3. Distribution map of Xenophyllum funkianum (left hand) and X. lorochaqui (right hand).