Sisyrinchium caratuvense C.D.Inácio & E.D.Lozano, 2022

Inácio, Camila Dellanhese, Lozano, Eduardo Damasceno, Antunes, Kelly, Báez-Lizarazo, Mabel Rocio & Eggers, Lilian, 2022, Exploring Sisyrinchium (Iridaceae) diversity in the Atlantic Forest Biome: three new species in S. sect. Viperella, Phytotaxa 541 (2), pp. 153-164 : 154-156

Sisyrinchium caratuvense C.D.Inácio & E.D.Lozano , sp. nov. ( Figs. 1 and 2 )

Diagnosis:— Sisyrinchium caratuvense is comparable to S. marchio , but differs by the presence of basal and cauline leaves (vs. cauline only), smaller flowers (12−15 mm vs. 17.9−27.2 mm in diam.) and narrower lower (1.3−1.8 mm vs. 3.3−7.9 mm wide) and upper valves (0.7−1.5 mm vs. 2.3−5.6 mm wide) of the spathes.

Type:— BRAZIL. Paraná: Campina Grande do Sul, Cume do Pico Caratuva , 15 January 2019 (fl, fr), E.D. Lozano et al. 4314 (holotype MBM!, isotypes ICN!, RB! SPF!) .

Perennial herb, erect to caespitose, 15–34.5(–44) cm tall. Rhizome short, roots fibrous and slender. Basal leaves, 1−3, plane, 49−140 × 1.3−3.3 mm, glabrous, acute to attenuate, margin entire, sheath 22.1−46 mm long, margin entire. Cauline leaves, 2−6, plane, ensiform to falcate, 17–62(–82) × 1.3–2.9(–3.5) mm, glabrous, attenuate, margin entire, sheath 9.2−20.7 mm long, margin ciliate. Angle between leaves and stem 2−25 degrees. Stem narrowly winged, 12−32.5(–41) × 0.12−0.2 cm, internodes 34−76 mm long. Inflorescence terminal. Rhipidium 1−2-flowered, pedunculate, peduncle 27−67 mm long. Spathes bivalved, lower valve 18.6−21.5(–29.3) × 1.3−1.8 mm, upper 14−21.3 × 0.7−1.5 mm, glabrous, acute to acuminate, membranaceous margin only on upper valve. Pedicel shorter than spathes, 11.5−17.7 mm long, glabrous. Perigon disk-shaped, yellow, 12−15 mm in diam. (measurement from photos). Tepals subequal, 6.5−7 × 2.5−2.6 mm, free, oblanceolate, acuminate, concolorous, glabrous. Filaments yellow, basally connate for 1.5−2 mm, then 0.5−0.7 mm free, ascending to patent, glabrous. Anthers yellow, versatile, 1.8−2.6 mm long. Ovary obovoid, 1−1.8 × 0.7−1.1(−1.5) mm, glabrous. Style yellow, 2.2 mm long, style branches 0.6−0.9 mm long, alternate to the stamens, ascending to patent. Capsule globose to subglobose, 3.3−3.9 × 3.4−3.9 mm, dull brownish yellow, glabrous. Seeds not seen.

Distribution and Habitat:— Sisyrinchium caratuvense is only known from within the boundaries of the Pico Paraná State Park, at the summit of the Camapuã, Caratuva, Ciririca and Tucum peaks. These mountains are located along the Serra do Ibitiraquire, between the municipalities of Antonina and Campina Grande do Sul, in the eastern portion of the Paraná state, in the Atlantic Forest Biome, Brazil ( Fig. 3 ). This region is well known for recent discovery of new endemic species such as Baccharis umbellata G.Heiden & Ribas ( Heiden & Ribas 2012) and Mimosa tucumensis Barneby ex Ribas, M.Morales & Santos-Silva ( Morales et al. 2012).

This new species occurs in high altitude grasslands, at an elevation range of 1735–1850 m. It can be found where vegetation is open and there is little competition for light. It grows over histosols, and can be found among rock outcrops.

Phenology: — Sisyrinchium caratuvense blooms from November to March and bears fruits immediately after flowering.

Conservation Status: —Vulnerable (VU, D2) according to the IUCN Red List guidelines ( IUCN 2019). Although the species is solely known from restricted areas in mountain tops with a small extent of occurrence (EOO <100 km 2) and area of occupancy (AOO <10 km 2), its distribution is included in a State Park, favouring its conservation. However, stochastic events (such as intense fires or drought) could drive the species to CR (Critically Endangered) in a short time.

Etymology: —The species epithet refers to the type locality, the Caratuva peak in the Paraná state, the second highest mountain peak in southern Brazil.

Paratypes: — BRAZIL. Paraná: Campina Grande do Sul, Serra do Ibitiraquire, Pico Caratuva, 6 February 2010 (fl), E.D. Lozano 214 (MBM!); Campina Grande do Sul, Serra do Ibitiraquire, Pico Ciririca, embaixo das placas, 28 March 2004 (fl), M.B. Scheer & A.Y. Mocochinski 553 (MBM!); Campina Grande do Sul, Serra do Ibitiraquire, Morro Camapuã, 3 February 2000 (fl, fr), O.S. Ribas et al. 3063 (MBM!); Campina Grande do Sul, Morro Camapuã, 2 March 2013 (fl), P. Larocca & G. Felitto 51 (MBM!); Campina Grande do Sul, Serra dos Órgãos [Serra do Ibitiraquire], Morro Tucum, 19 November 1999 (fl), J. Cordeiro et al. 1635 (HUCS!, MBM!).

Taxonomic relationships:— The first collection of S. caratuvense was identified as S. vaginatum , a misdetermination that pervades most of herbarium specimens bearing cauline leaves, due to the synonymization proposed by some researchers (e.g. Chukr & Capellari Jr. 2003), and to the poor recognition of many species described by Ravenna. Although bearing similar flowers, characters such as presence of basal leaves, size of cauline leaves, length of sheaths, length of the lower valve of the spathes, and length of style and style branches can be used to differentiate S. caratuvense from S. vaginatum .

The species most similar to S. caratuvense is S. marchio ( Vellozo 1829: 273) Steudel (1841: 596) . Sisyrinchium caratuvense can be distinguished from it by the presence of basal leaves, narrower stem (1.2–2 mm vs. 3.2–6.8 mm wide), ciliate margin of the leaf sheaths (vs. entire margin), and narrower lower (1.3–1.8 mm vs. 3.3–7.9 mm wide) and upper valve of the spathes (0.7–1.5 mm vs. 2.3–5.6 mm wide). Moreover, several flower features present smaller measurements in relation to flowers of S. marchio (e.g. flower diameter, tepals length and width, free filament length, anther length and style branches length, Table 1 ). Sisyrinchium caratuvense is endemic to Serra do Itabitirique, while S. marchio and S. vaginatum have a wider distribution ( Eggers & Inácio 2020).

Figures

FIGURE 1. Habit of Sisyrinchium caratuvense C.D.Inácio & E.D.Lozano. From E.D. Lozano et al. 4314 (ICN). Drawing by Rafaella Marchioretto.

FIGURE 2. Sisyrinchium caratuvense C.D.Inácio & E.D.Lozano. A. Habit. B. Flowering stems. C. Inflorescence with flower and fruit. D. Spathe valves of unequal size (blue arrows). E. Flower in frontal view. F. General view of the species habitat, Paraná, Brazil. From E.D. Lozano et al. 4314 (MBM).

FIGURE 3. Distribution map of Sisyrinchium caratuvense (square), S. usneoides (triangle), and S. iguazuanum (circle) in South and Southeast Brazil, and Argentina border.