Centaurea susannae Invernón & Devesa, 2012

Invernón, Vanessa R., Devesa, Juan Antonio & López, Eusebio, 2012, Centaurea susannae (Cardueae, Compositae): A new species from protected coastal areas in Portugal, Phytotaxa 74 (1), pp. 41-46 : 42

Centaurea susannae Invernón & Devesa , sp. nov. ( Fig. 1 )

Type: — PORTUGAL. Algarve : Cabo de São Vicente, roadside, 37º1'36.2" N, 8º59'22.9" W, 6 May 2010, V. R . Invernón & J. A . Devesa (holotype COFC 57935 !) .

Perennial herb, unarmed except the involucral bracts, green, with eglandular uniseriate multicellular hairs and arachnoid unicellular hairs. Stems up to 50 cm tall, erect or ascendant, usually branched from the base. Leaves up to 120 × 50 mm, decreasing in size towards the top of the stem, lyrate-pinnatipartite or lyrate-pinnatisect, with 1–3 pairs of lateral lobes, triangular or ovate, and the terminal lobe ovate-lanceolate, acute, all with a conical mucro of up to 0.8 mm or a spinule of up to 2 mm in those near the inflorescences; the basal narrowed at the base, usually withered at anthesis; the cauline sessile, auriculate at the base. Capitula homogamous, radiant, with the outer flowers neutral and the central ones hermaphrodite, solitary, terminal, sessile, surrounded and sometimes surpassed by the upper leaves. Involucre 15–20 × (9–) 11–18 mm, ovoid, round at the base, glabrous. Involucral bracts imbricate, apparently arranged in 5–6 series, greenish or greenish-yellow, getting purple towards the upper part of the capitulum; the outer bracts ovate to ovate-oblong, strongly appressed, with a palmate-spinose apical appendage, not decurrent, with 3–5 divergent spines, patent or reflexed; the middle similar but with an appendage bearing 5–6(–7) spines; the central 2.5–5 mm long, slightly exceeding the inner ones; the inner up to 16 mm long, linear or linear-spatulate, glabrous, without an appendage, with a scarious apex. Corolla of sterile flowers 17–23 mm long, glabrous; tube whitish; limb purple or bright pink, with (3–)4(–5) lobes, lanceolate or linear-lanceolate, inconspicuously papilloseglandular, with sinuses at different heights. Corolla of hermaphrodite flowers 16–20 mm long; tube whitish; limb 9–11 mm long, whitish at the base and pinkish-purple towards the apex, with 5 lobes, linear, inconspicuously papillose-glandular, two of which with longer sinuses. Stamens with papillose filaments; anthers 6–9 mm long, violet, with basal appendages 0.3–0.6 mm long, membranaceous and often lacerate. Style whitish, purple distally, with stigma branches separated at the apex. Achenes 3.5–4.5 × 1.9–2.5 mm, columnar-obovoid, slightly compressed, elliptical in section, yellowish (with chestnut-brown longitudinal lines), laxly appressed-sericeous; apical plate with a rudimentary cylindrical nectary; insertion areole 0.9–1.8 × 0.5–1.5 mm, lateral-adaxial, rhombic in frontal view, with elaiosome fleshy, yellowish. Pappus double, persistent, the outer with 4–6 rows of paleae 0.2–1.8 mm long, erect or erect-patent, unequal (increasing inward), lanceolate, barbellate-scabrid, straw- or chestnut-brown to reddish; the inner with 1 row of paleae 0.4–0.6 mm long, setaceous, flattened, erect or converging, blackish-chestnut.

Figures

FIGURE 1. Centaurea susannae: A. Habit. B. Basal leaf. C. Detail of a node and leaf insertion. D. Capitulum. E. Outer involucral bract. F. Middle involucral bract. G. Inner involucral bract. H. Section of a capitulum. I. Sterile flower corolla. J. Fertile flower corolla. K. Fertile flower corolla sectioned to show the insertion of the stamens. L. Detail of the style and stylar branches. M. Pappose achene. N. Detail of the pappus. (All illustrations made from the holotype. Drawings by Rodrigo Tavera).