Senecio doriiformis Candolle (1838a: 352)

Calvo, Joel, Álvarez, Inés & Aedo, Carlos, 2015, Systematics of Senecio section Crociseris (Compositae, Senecioneae), Phytotaxa 211 (1), pp. 448-450 : 448-450

9. Senecio doriiformis Candolle (1838a: 352) . Type: Lebanon, Libaniis, 1837, P.M.R. Aucher-Eloy 3440 (lectotype, designated by Nordenstam (1989b: 65), G-DC-204944 image!; isolectotypes, G-96297 image!, G-150318 image!).

Perennial herb. Rhizome thick, from where usually arise several shoots. Stem 37–95 cm, erect, densely leaved, corrugated, solid, sometimes ramificated, glabrescent, sometimes weakly arachnoid, base without remnants of old leaves or tufts of hairs. Basal leaves ca. 3.8 cm long, ca. 3.5 cm wide, withering early, ovate-rhomboid to broadly lanceolate (ratio basal leaf width / basal leaf length = ca. 0.92), obtuse, attenuate to ± truncate, sometimes subcordate, with a petiole up to 5.5 cm long, entire to denticulate, glabrescent, concolorous. Cauline leaves 11–26; middle cauline leaves 5.3–13 cm long, 1.7–5.9 cm wide, alternate, ovate to lanceolate (ratio middle leaf width / middle leaf length = 0.20–0.66), obtuse, ± truncate to attenuated into a petiole 0.5–3.2 cm long, sometimes asymmetric, entire to denticulate, sometimes slightly dentate (teeth 0.5–2.5 mm deep), glabrescent to covered with scattered trichomes (trichomes 0.2–0.4 mm long), tertiary venation conspicuous (unless on dry); upper cauline leaves 1.7–10.5 cm long, 0.3–3.2 cm wide, ovate to lanceolate (ratio upper leaf width / upper leaf length = 0.11–0.59), acute to obtuse, sessile, sometimes abruptly attenuated into a petiole up to 0.7 cm, entire to denticulate (denticles ca. 1 mm long), glabrescent to covered with scattered trichomes. Synflorescence 4.5–38 cm long, corymbose to corymbose paniculate, with linear-lanceolate bracts. Capitula (3–)10–22(–47), 20.1–25.8 mm in

38 • Phytotaxa 211 (1) © 2015 Magnolia Press

CALVO ET AL.

diam.; involucre 6.1–9.5 mm in diam., 6–8 mm long, narrowly cupuliform; involucral bracts (10–)12–13(–14), 4–6.4 mm long, 1.4–2.3 mm wide, with scarious margin 0.3–0.7 mm wide, ensiform, acute, weakly 1–3-keeled, apex without a black spot, glabrescent to weakly arachnoid (trichomes 0.1–0.2 mm long); supplementary bracts (5–)6–7(–8), 2.1–5.1 mm long, 0.2–0.7 mm wide, subulate, without scarious margin, a half to almost as long as involucral bracts, glabrescent to weakly arachnoid (trichomes ca. 0.1 mm long), not imbricated. Ligulate florets 8–10, 9.5–13.1 mm long, yellow; tubular florets 6.8–9.2 mm long, 0.7–1.5 mm in diam., yellow. Achenes 2.9–5.1 mm long, 1–1.5 mm wide, subcylindrical (ratio achene width / achene length = 0.24–0.46), shorter than pappus (ratio achene length / pappus length = 0.47–0.66), with 11–12 ribs, glabrous or with some scattered intercostal trichomes up to 0.1 mm long; pappus 5.7–9.1 mm long, whitish. Chromosome number: unknown.

Etymology: — The specific epithet doriiformis probably refers to the slight similarities with S. doria regarding the size and architecture of the capitulum. Certainly, the capitulum of S. doriiformis is one of the smallest within Senecio sect. Crociseris .

Discussion: — Senecio doriiformis is a distinctive species in the Anatolian Crociseris because of its habit, which displays several ramificated shoots from the same rhizome, usually forming tufts. Moreover, it has numerous cauline leaves not strongly decreasing in size up the stem, with a conspicuous tertiary venation (better observed on dried material), and its basal leaves are withering early. Such type of habit is shared with S. pyrenaicus from the Iberian Peninsula, which has considerably larger capitula, and a larger number of involucral bracts (15–28 vs. 10–14). It is a variable species mainly regarding the shape of leaves, which is useful to distinguish the two subspecies recognized. Disagreeing with Nordenstam (1989b), the leave margin (entire in subsp. doriiformis vs. slightly denticulate-crenate in subsp. orientalis ) is not useful to distinguish between the two taxa.