Senecio eliseae J. Calvo, 2015

Calvo, Joel, 2015, Senecio eliseae (Compositae, Senecioneae), a new species from the southern Ecuadorian Andes, Phytotaxa 230 (1), pp. 69-74 : 70-73

Senecio eliseae J. Calvo , sp. nov. Figs. 1 (A, B) & 2

Type: — ECUADOR. Morona-Santiago: Gualaceo-Limón, km 27.5, turnoff towards antennas, 3°00’S 78°39’W [wrongly indicated as 3°02’S on the original label], 3530 m, 27 Dec 1990, P. M. JØrgensen, C. Ulloa & B. Øllgaard 92891 (holotype: QCNE-57313, isotypes: MO-04850796, QCA- 146684).

Senecio eliseae differs from the other discoid Senecio species from the paramos in its suffrutescent habit with ascending stems that are leaved only on the upper half, nodding capitula, and glandular-hirsute indumentum on the stem, leaves, and synflorescence.

Erect suffrutescent herb, rhizomatous. Rhizome fuchsia-coloured and covered with glandular-hirsute indumentum, at least the young parts. Stem 60–150 cm, erect, leaved only on the upper half, corrugated, fistulous, scarcely branched, glandular-hirsute. Basal leaves absent. Cauline leaves 5–9.5 cm long, 0.9–1.9 cm wide, alternate, narrowly lanceolate to oblong, acute, semiamplexicaul, crenate to sinuate (sometimes denticulate at the lower half), revolute, glandular-hirsute on both faces (denser on the adaxial face). Synflorescence pseudocorymbose, with bracts similar to the upper cauline leaves. Capitula (3–)7–10(–20), discoid, nodding; involucre 22–28 mm in diam., 10–13 mm long, bell-shaped; involucral bracts 21–27, 9.4–12.5 mm long, 2.5–4.5 mm wide, with scarious margin 0.5–1.4 mm wide (often fimbriate), lanceolate, abruptly attenuate, smooth, glandular-hirsute; supplementary bracts 9–14, 8.2–10.2 mm long, 1.2–2 mm wide, subulate, without scarious margin, a half to almost as long as involucral bracts, glandular-hirsute. Discoid florets ca. 150, 8.4–10 mm long, 1.3–1.8 mm in diam., yellow; style branches truncate with apical sweeping hairs. Immature achenes glabrous; pappus whitish. Chromosome number: unknown.

Distribution and habitat: —The new species is only known from the paramo nearby La Loma de la Virgen, on the road between Gualaceo and Limón (Morona-Santiago); humid shrubby paramo with Diplostephium floribundum , Pentacalia nitida , Pentacalia vaccinioides , Senecio otophorus , etc.; elevations of 3200–3550 m.

Etymology: —The specific epithet honors Élise Ross-Nadié, for her unconditional support during the fieldwork.

Additional specimens examined (paratypes): — ECUADOR. Morona-Santiago: road Gualaceo-El Limón, from the pass towards El Limón, 3200–3400 m, 8 Feb 1989, H. Werff & W. Palacios 10479 (MO-3825969, QCNE-25946). Azuay / Morona-Santiago: road to antennas in the pass on Gualaceo-Limón road, 3°00’S 78°39’W [wrongly indicated as 3°01’S on the original label], 3500 m, 27 Dec 1990, B. Øllgaard, P.M. JØrgensen & C. Ulloa 98552 (AAU, QCA-161379).

Discussion: — Senecio eliseae is easily recognized by the combination of the following characters: suffrutescent herb with erect branches only leaved on the upper half, discoid yellow nodding capitula, and glandular-hirsute indumentum on stem, leaves, and synflorescence.

Senecio eliseae is morphologically close to S. hastatifolius Cabrera (1955: 231) from Peru and Bolivia. These species differ in the number and shape of the involucral bracts (18–20, subulate, ca. 1 mm wide in S. hastatifolius ( Fig. 1 C ) vs. 21–27, lanceolate, abruptly attenuate, 2.5–4.5 mm wide in S. eliseae ). The capitula of S. hastatifolius are ± erect, held by thin pedicels, while the capitula of S. eliseae are clearly nodding, held by thicker pedicels. The leaves are also quite different (revolute, ± crenate in S. eliseae vs. flat, denticulate in S. hastatifolius ), as well as the habit; S. hastatifolius is a branched suffrutescent herb while S. eliseae has erect branches usually only branched at the synflorescence.

The habit, leaf morphology, and indumentum of S. eliseae resemble that of S. formosus Kunth in Humboldt et al. (1818: 138), another species occurring throughout the paramo from Venezuela to Bolivia (Ávila et al. in Bernal et al. 2015). Since the latter species displays purple-radiate capitula, any confusion is very unlikely. Likewise, S. ayapatensis Schultz Bipontinus ex Weddell (1856: 129) from Bolivia and Peru has a habit, leaf morphology, and indumentum that are similar to that of S. eliseae but the capitula are radiate instead of discoid.

In Ecuador, S. eliseae has been misidentified as S. tephrosioides . This is understandable because both species display yellow discoid nodding capitula ( Fig. 1 E ), and the latter grows at the type locality of S. eliseae . However, they are different in several characters. Senecio eliseae is a suffrutescent herb with erect branches only leaved on the upper half while S. tephrosioides is a perennial herb with basal leaves well developed and decreasing in size up the stem ( Fig. 1 D ). The indumentum is another useful character to distinguish both species (glandular-hirsute in S. eliseae vs. glabrescent to weakly arachnoid, eglandular in S. tephrosioides ).

Figures

FIGURE 1. A–B. Senecio eliseae. A. Habit. B. Synflorescence. Plant from the type locality. C. Senecio hastatifolius. Detail of the involucral bracts. Isotype (LP-000511). D–E. Senecio tephrosioides. D. Habit. E. Synflorescence. Plant photographed at laguna El Voladero (El Ángel, Carchi) (not collected).