Senecio hortensiae A. Teles, 2013

Teles, Aristônio Magalhães & Freitas, Fernanda Santos, 2013, Senecio hortensiae (Senecioneae, Asteraceae): a new species from Espírito Santo, Brazil, Phytotaxa 142 (1), pp. 46-50 : 46-49

Senecio hortensiae A. Teles , sp. nov. ( Figs 1–2 )

Differs from Senecio graciellae Cabrera (1957: 221) in its leaves 8.2–10.5 × 1.2–2.1 cm, margins entire, lax capitula and peduncles 8–14 mm long (versus leaves 20–25 × 2.5–3 cm, margins 5–6- dentate, capitula congested and peduncles 2–3 mm long).

Type :— Brazil. Espírito Santo: Pancas, Parque Nacional dos Pontões Capixabas, Lajinha. 19°11′29″S 40°46′29″W, 05 August 2006, A. P . Fontana , C . Esgario , R . Louzada , C . Moreira & D. H . Krause 2344 (holotype RB!, isotype MBML) .

Shrubs to 1.0 m tall. Stem 12 mm in diameter, simple, striate, pithy, glabrous, basally scarred. Leaves densely grouped at the median part of the stem, sessile, alternate, blades oblanceolate, 8.2–10.5 cm long, 1.2–2.1 cm wide, apex acute, base broadened, penninerved, secondary veins inconspicuous on both surfaces, laminar surface rugulose, densely lepidote, and sparsely arachnoid on both sides, margins entire. Capitulescence terminal, paniculiform, lax. Capitula heterogamous, radiate, pedunculate; peduncles 8–14 mm long, densely lepidote, and sparsely arachnoid, bracteolate; bracteoles lanceolate, ca. 1.2 mm long, 1 mm wide, ciliate. Involucre cup-shaped, 6 mm long, 5 mm wide. Involucral bracts 6, scarious, outer 3 lanceolate, margins entire, apex acute-acuminate, ciliate, inner 3 oblong, margins entire, apex acute, ciliate. Inflorescence axis (receptacle) convex, alveolate. Ray florets 4–5, pistillate, corolla liguliform, yellow, tube 3 mm long, limb 5 mm long, 3- lobed; style 5.5 mm long, branches straight, 1.5 mm long. Cypsela 1.5 mm long, turbinate, glabrous, 6- costate; pappus 3–3.5 mm long, bristles barbellate, persistent. Disk florets perfect, 8–11, corolla tubular, yellow, 5.5 mm long, 5- lobate, lobes 1 mm long; filaments with anther collar straight, anthers ca. 1.5 mm long, inserted, base sagittate, connective with an oblong appendage 0.5 mm long; style 4.5 mm long, branches diverging, 1 mm long, apex obtuse, with a short, sterile pappilose appendage, crowned by simple, divergent trichomes. Cypsela 1.5 mm long, turbinate, 6- costate, glabrous; pappus 3–4 mm long, bristles barbellate, persistent.

Distribution and ecology:— This new species is endemic to the Parque Nacional dos Pontões Capixabas, in the Pancas municipality, Espírito Santo state, Brazil ( Figs 2A and 3 ). In the only known population, the species was found growing on granitic rocks in the mountain tops. This area is one of the last remnants of Atlantic Forest in Espírito Santo state, with interesting geological formations known locally as "Pontões".

Conservation Status:— Senecio hortensiae , although occurs within a national park, according to IUCN Red list category ( IUCN 2012), is considered Endangered (EN subcriteria D - population size estimated to number fewer than 250 mature individuals) as it grows in a highly specialized habitat and is known from a single population, found in an area difficult to access.

Phenology:— Flowering and fruiting specimens were collected in August.

Eponymy:— The specific epithet is in honor of Prof. Dr Hortensia Pousada Bautista, a good friend and an excellent expert in Brazilian Asteraceae , and who has greatly contributed to the formation of new synanterologists in Brazil.

Discussion:— Senecio hortensiae belongs to section Adamantina as it has lax cauline leaves and the densely clustered sessile basal leaves, 6 involucral bracts, the radiate capitula and the glabrous cypsela . The new species seems to be closely related to the allopatric species S. graciellae , the differences of which were already mentioned in the species diagnosis and below in the key to identification of species of section Adamantina .

Nine species are presently assigned to Senecio section Adamantina : Senecio adamantinus Bong. , S. albus J.N. Nakaj. & A. Teles , S. caparaoensis Cabrera , S. colpodes Bong. , S. dumetorum Gardner , S. gertii Zardini , S. graciellae Cabrera , S. hortensiae A. Teles and S. pseudostigophlebius Cabrera. All species are exclusively from southern and south-eastern Brazil, except for S. adamantinus , that extends to central Brazil.

Figures

FIGURE 1. Senecio hortensiae. A. Habit. B. Leaf indumentum. C. Capitula. D. Bracteole. E. Ray floret. F. Disk floret. G. Stamens. H. Style branches. (All illustrations made from the holotype. Drawings by Cristiano Gualberto dos Santos).

FIGURE 2. Senecio hortensiae. A. Habitat. B. Capitulescence. C. Capitula. D. Capitula detail. (Photos by A.P. Fontana).

FIGURE 3. Distribution of Senecio hortensiae.