Hysterionica matzenbacherii A.A.Schneid., 2012

Schneider, Angelo Alberto & Boldrini, Ilsi Iob, 2012, Hysterionica matzenbacherii, a new species of Astereae (Asteraceae) from Brazil, Phytotaxa 49 (1), pp. 50-54 : 51-52

Hysterionica matzenbacherii A.A.Schneid. , sp. nov. ( Fig. 1 )

Hysterionica pinnatiloba Matzenb. & Sobral affinis sed follis incisis ad partitis, limbo irregulariter dentato ex medio ad apice differt.

Type:– BRAZIL. Santa Catarina: Lauro Müller, Serra do Rio do Rastro , rodovia SC-438, 12 December 1996, N. I . Matzenbacher 2218 (holotype ICN!, isotype MO!) .

Annual herbs, 10–22 cm tall, branched at the base or unbranched; roots fasciculate; stems herbaceous, erect or ascending, terete to subterete, striate, sparsely pilose, leafy from the base. Leaves crowded at the base of the stem, alternate, internodes 1–5 mm, sessile, blades chartaceous, obovate to obtrullate, 5.0–10.5 × 0.8–2.5 cm, margins irregularly incised to lobate (except at base), segments acute, denticulate 2–12 × 1–3 mm, base longattenuate, nearly half of the blade, clasping, apex acuminate, strigose adaxially, sparsely strigose abaxially. Capitula solitary (2), heterogamous, radiate, terminal, pedunculate, peduncles 3.5–5 cm long, pilose; involucre hemispheric, 4.0–5.0 × 9.0– 12 mm; phyllaries 2–3 seriate, subequal, lanceolate, 4.1–4.6 × 0.5–0.6 mm, dorsally glandular and sparsely pilose, acute; receptacle convex, alveolate, epaleate. Radiate florets pistillate, 1-seriate; corolla white, limb 2.3–2.7 × 0.5–0.8 mm, truncate to slightly 3 lobed, tube 1.8–2 mm long, style 3–4 mm (including branches). Disk florets bisexual, corolla yellow, tubular, tube 3.5–4 × 0.5–0.8 mm, 5-lobed at the apex, lobes 0.2-0.5 mm long; style 4–4.5 mm (including branches), branches linear, acute, dorsally pilose. Cypselae 1–1.2 mm long, slightly compressed, obconic, marginally 2-nerved, pilose, eglandular; pappus whitish, 2.8–4 mm long, of two series of bristles, the outer series 0.2–1 mm long, the inner series 2–3.2 mm long.

Distribution:— Southern Brazil. Known only from 900–1,400 m in elevation. Serra do Rio do Rastro (28°23’45.15” S, 49°32’37.14” W), part of the eastern edge of the Serra Geral plateau, municipality of Lauro Müller, Santa Catarina ( Fig. 2 ).

Phenology:— Flowering and fruiting specimens have been collected in January.

Habitat: — Hysterionica matzenbacherii is known from a single site growing directly attached to bare rock at the edges of outcrops and cliffs on steep slopes subject to constant fog and high humidity. These outcrops occur in the transitional zone of cloud forests and dense forests of the Atlantic Rainforest.

Conservation status: — The new species, according to IUCN Red list category ( IUCN 2010), is considered Endangered (EN subcriteria D1- very small or restricted population).

Etymology: — The new species honours Nelson Ivo Matzenbacher, collector of the type specimen. Matzenbacher contributed enormously to our knowledge of the Asteraceae from Rio Grande do Sul and Santa Catarina states in southern Brazil.

The new species is morphologically most similar to H. pinnatiloba and H. pinnatisecta with which it shares an herbaceous habit and capitula with white radiate florets. It is different from them in having leaves with irregularly incised to lobed margins (except in the basal part of the leaf), whereas the leaves of H. pinnatiloba are pinnatilobed and those of H. pinnatisecta are pinnatisect throughout the length of their leaf margins.

Another important difference is the length of the limb of radiate florets. Hysterionica matzenbacherii has shorter limbs (2.3–2.7 mm) than H. pinnatiloba (4–5 mm) and H. pinnatisecta (8–8.5 mm).

Hysterionica matzenbacherii , just like H. pinnatisecta , grows in crevices in the basalt cliffs of the formation of Rio do Rastro, ranging from 900-1,400 m in elevation.

Additional collecting trips to the area failed to recover this population of H. matzenbacherii or other populations of this species.

Figures

FIGURE 1. Hysterionica matzenbacherii. A. Habit. B. Detail of adaxial leaf indument. C. Outermost to innermost phyllaries. D. Pistillate radiate floret. E. Bisexual disk floret. F. Detail of anthers. G. Style apex of radiate floret. H. Style apex of disk floret. I. Mature cypsela. J. Detail of pappus bristle. Illustration by Anelise Scherer based on Matzenbacher 2218 (ICN).

FIGURE 2. Habitat of Hysterionica matzenbacherii at Serra do Rio do Rastro (28°23’45.15” S, 49°32’37.14” W), municipality of Lauro Müller, Santa Catarina. Photographs by A.A. Schneider.