Sisyrinchium flabellatum Aita & L.Eggers, 2013

Aita, Adriana M., Chauveau, Olivier, Souza-Chies, Tatiana T. & Eggers, Lilian, 2013, Two new species of Sisyrinchium (Iridaceae) from Subtropical Highland Grasslands of Southern Brazil, Phytotaxa 88 (1), pp. 9-18 : 13-17

Sisyrinchium flabellatum Aita & L.Eggers , sp. nov. ( Figs. 2 and 3 E–I )

A S. palmifolio L. foliis basalibus 9.6–17.4 cm longis, 0.3–0.8 cm latis; tepalis 7.5–9.7 mm longis, 2.5–3.1 mm latis; stylis 0.7–1 mm longis, stylorum ramis 3.6–4.5 mm longis distincto est.

Type:— BRAZIL. Rio Grande do Sul: Jaquirana , 893 m, 22 October 2010, L . Eggers & T. T . Souza-Chies 584 (holotype ICN!)

Perennial herb, erect, up to 24 cm, typically with entangled dry leaves at base. Rhizome inconspicuous, basal thick roots intermixed with thin ones. Leaves basal, distinctive equitant, 9.6–17.4 × 0.3–0.8 cm, glaucous but flushed purple proximally, dark when dry, ensiform, slightly verrucose, veins apparent, not prominent, apex acute, margins thin. Scape simple, mostly erect, broadly winged, node markedly purplish, 7.7–15.5 × 0.4–0.7 cm, with a terminal bract. Bract with basally scarious margin, 5.4–8.4 cm long, followed by a second bract, 2.5–5.2 cm long. Inflorescence lax, of 4–9 rhipidia. Rhipidia usually pedunculate, first peduncle conspicuous, 5–11 mm long, others 0–10.3 mm long, enclosed by one pair of spathes. Spathes acute, margin scarious with a purplish line, nodes purplish, 13.7–23.8 mm long. Pedicel glabrous, usually longer than spathes, 14–28 mm long. Flowers yellow. Tepals subequal, reflexed, elliptic to oblanceolate, acute to acuminate, adaxial side with prominent central vein, abaxial side devoid of marked veins, 7.5–9.7 × 2.5–3.1 mm. Filaments yellow, glabrous, basally connate for less than 1 mm, free portion 1.5–2 mm, ascending to patent. Anthers yellow, dorsifixed, incurved at dehiscence, 4-5 mm long. Ovary glabrous, 2–3 × 1.2–2 mm. Style yellow, glabrous, 0.7–1(–1.9) mm long, style arms alternate with stamens, ascending to patent, 3.6–4.5 mm long, stigma truncate. Capsules globose to oblate, dark brown, 4.8–6.6 × 4.7–7.2 mm.

Distribution and Habit: — Sisyrinchium flabellatum was collected in the state of Rio Grande do Sul ( Fig. 4 ), in grassland vegetation marked by rocky outcrops and cactus plants. The only elevation record is of 893 m a.s.l. The locality falls within the Atlantic Forest Biome. Phenology: —Flowering and fruiting from October to January.

Conservation Status: —According to the IUCN Red List guidelines ( IUCN 2001), the species is considered to be Critically Endangered (CR, subcriteria B2 (a) and (biii): continuing decline of extent of occurrence and a decline of quality of habitat) due to the growing expansion of monoculture areas in Subtropical Highland Grasslands.

Etymology: —The specific epithet refers to the fan-like arrangement of the leaves. Sisyrinchium flabellatum can be easily distinguished by its distinctive equitant phyllotaxy.

Additional specimens examined (paratypes):— BRAZIL. Rio Grande do Sul : Cambará do Sul em direção a São Francisco de Paula , January 1948 (fr), B. Rambo ( PACA 36615 !); Porto Alegre, coletada da coleção viva do Jardim Botânico, planta originalmente trazida de Rio Grande do Sul, Jaquirana , November 2008 (fr), L. Eggers ( ICN 190713 !) .

Sisyrinchium flabellatum was first collected by Rambo in January of 1948 and tentatively identified as S. macrocephalum Graham (1833: 176) (a synonym of S. palmifolium, Ravenna 1984 ). The only other material was collected in April of 2007. This plant was part of a living collection of Iridaceae maintained at the Botanical Garden of Porto Alegre, Fundação Zoobotânica do Rio Grande do Sul. We returned to the locality in October of 2010 and collected the species again. It grows typically associated with cactus over and among rocks and the senescent leaves fall around the plant, creating a very remarkable interesting surround.

The morphology of the species is strongly distinctive. The main discriminant features are the equitant phyllotaxy, the glaucous leaves, the large inflorescence and the small reflexed tepals. A comparison with the description of S. palmifolium presented by Heaton & Mathew (1998) shows that it differs in the erect aspect of the inflorescence, with longer peduncles. Furthermore, measurements of S. flabellatum contrast with those of S. palmifolium in the size of leaves (9.6–17.4 × 0.3–0.8 cm against 80 × 1–1.5 cm), tepals (7.5–9.7 × 2.5–3.1 mm against 17–18 × 8–9 mm) and style (connected part 0.7–1(–1.9) mm, and free part 3.6–4.5 mm, against respectively 1.5 and 5 mm) ( Table 2).

Sisyrinchium flabellatum is also close to S. nidulare , which was not described rigorously since it was first considered a variety of S. palmifolium . Comparisons made against selected exsiccates of S. nidulare showed that S. flabellatum differs in the size of leaves (9.6–17.4 × 0.3–0.8 cm against 15.8–44.8 × 0.2–0.6 cm), terminal bract (5.4–8.4 cm against 6.4–17.4 cm), external spathe length (13.7–23.8 mm against 33.6–90 mm) tepals (7.5–9.7 × 2.5–3.1 mm against 17.3 × 6.8 mm) ( Table 2).

Figures

FIGURE 2. Sisyrinchium flabellatum Aita & L.Eggers. A. Habit B. Inflorescence C. Flower in frontal view. From L. Eggers & T.T. Souza-Chies 584 (ICN!), drawings by Edson Luís de Carvalho Soares.

FIGURE 3. Sisyrinchium antemeridianum Aita & L.Eggers. A. Habit. B. Inflorescence and tepals in abaxial side. C. Flowers and fruits. D. Habitat. Sisyrinchium flabellatum Aita & L.Eggers. E. Rhipidium, flower and fruits. F. Flowers. G. Habit. H. Habitat. I. Inflorescences.

FIGURE 4. Distribution map of Sisyrinchium antemeridianum (circles) and S. flabellatum (star) in Southern Brazil.