Sisyrinchium iguazuanum C.D.Inácio, L.Eggers & Chauveau, 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 : 162-163

Sisyrinchium iguazuanum C.D.Inácio, L.Eggers & Chauveau , sp. nov. ( Figs. 6 and 7)

Diagnosis:— Sisyrinchium iguazuanum resembles S. marchioides by the yellow, proximally white perigon; however, it is distinguished by the smaller lower valve of the spathes (8.8–15.3 × 0.7–1.8 mm vs. 15.6–27.1 × 2.2–3.3 mm), shorter upper valve (7.8–14.2 mm vs. 17.1–24.4 mm long), smaller flowers (10–12.2 mm vs. 15–20.3 mm in diam.) and pedicels shorter than spathes (vs. moderately exserted).

Type:— BRAZIL. Paraná: Abelardo Luz , BR 280 , aprox. km 153 (23 km da cidade de Palmas), 988 m, 19 November 2010, L. Eggers & T. T. Souza-Chies 612 (holotype ICN!, isotypes MBM!)

Perennial herb, caespitose to rhizomatous 11–29.5 cm tall. Rhizome short to long, roots fibrous and slightly thickened. Basal leaves absent. Cauline leaves, 3−7, plane, falcate, 11−20(–25.8) × 1.6–2 mm, glabrous, attenuate, margin entire, sheath 3.6−6.5 mm long, margin entire. Angle between leaves and stem 12−17 degrees. Stem narrowly winged, 15−28.5 × 0.09−0.19 cm, internodes 19−32 mm long. Inflorescence terminal. Rhipidium 1−2-flowered, pedunculate, peduncle 11.1−25 mm long. Spathes bivalved, lower valve 8.8−15.3 × 0.7−1.8 mm, upper 7.8−14.2 × 1.1−1.7 mm, glabrous, acute to acuminate, membranaceous margin only on upper valve. Pedicel shorter than spathes, 6.9−14 mm long, glabrous. Perigon disk-shaped, yellow, proximally white, followed by a brown to vinaceous coloured ring, 10−12.2 mm in diam. (measurements from spirit-preserved and dry preserved flowers). Tepals subequal, 5.2−6.2 × 2−2.3 mm, free, oblanceolate, attenuate, concolorous, glabrous. Filaments yellow, basally connate for 0.5−0.7 mm, then 1.5−1.7 mm free, ascending to patent, glabrous. Anthers yellow, versatile, 3.5 mm long. Ovary obovoid, 1.3−1.7 × 1−1.1 mm, glabrous. Style yellow, 0.9−1.5 mm long, style branches 2−2.4 mm long, alternate to the stamens, ascending to patent. Capsule globose to subglobose, 3.1−4.9 × 2.8−4.7 mm, dark brown, glabrous. Seeds not seen.

Distribution and Habitat:— Sisyrinchium iguazuanum occurs in west of the states of Paraná and Santa Catarina, in the Plateau of the Paraná basin, in the Atlantic Forest biome, Brazil ( Fig. 3 ). It was also collected in eastern Misiones, Argentina. The species grows in dry to humid grasslands, bogs, thin soil associated with rock outcrops, and roadsides, at an elevation range of 800–1000 m.

Phenology: —Flowering and fruiting from September to February.

Conservation Status: —Near Threatened (NT) according to the IUCN Red List guidelines ( IUCN 2019).Although the taxon meets the area requirements under criterion B for threatened (EOO <20,000 km 2 and AOO <500 km 2), the number of locations is superior to 10. Habitat loss is increasing and habitat quality is decreasing within the species range by agricultural expansion of crops and silviculture. Regarding preserved areas, the species has a single record in an indigenous reserve (Reserva Indígena de Mangueirinha, Paraná).

Etymology: —The specific epithet refers to the distribution of the species that is generally associated to the Iguaçu river basin.

Paratypes: — BRAZIL. Paraná: Cantagalo, rodovia BR 277 , 27 February 1987 (fl, fr), A. C. Cervi 2515 ( UPCB!, MBM!, CTES!); Clevelândia, Fazenda Sant’Ana, 29 December 1956 (fl), L. B. Smith et al. 9567 ( GH!, R!, US!); Coronel Vivida, Posto indígena, Mangueirinha, 30 September 1992 (fl), N. R. Marquesini et al. s.n. ( MBM 202533 !, UPCB 211866 !); Guarapuava, Fazenda Três Capões, 9 December 1969 (fl, fr), G. Hatschbach 23187 ( MBM!); Guarapuava, Rio Campo Real, 4 December 1969 (fl), G. Hatschbach & P. Ravenna 23104 ( MBM!); Mangueirinha, Reserva Indígena de Mangueirinha , 16 September 2009 (fl), J. M. Silva et al. 7353 ( MBM!); Mariópolis, BR 280 , direção Pato Branco – Palmas, após Mariópolis, 31 October 2008 (fl), L. Eggers & T. T. Souza-Chies 383 ( ICN!); Marmeleiro, estrada Marmeleiro−Campo Erê, 21 February 1971 (fl, fr), G. Hatschbach 26451 ( MBM!, CTES!); Santa Catarina: Chapecó, Capetinga, 24 January 1952 (fl), R. Reitz 4294 ( NY!, US!); Chapecó, Fazenda Campo São Vicente, 24 km oeste de Campo Erê, 26−28 December 1956 (fl), L. B. Smith et al. 9471 ( GH!, US!); São Lourenço do Oeste , 16 km west of São Lourenço , 6 December 1964 (fl, fr), L. B. Smith & R. Klein 13662 ( GH!, NY!, US!) . ARGENTINA. Misiones: Gral. Manuel Belgrano, Campinas de América, Cementerio , 16 December 2006 (fl, fr), H. A. Keller & F. E. Gatti 3857 ( CTES!) .

Taxonomic relationships: —Specimens of S. iguazuanum were identified as S. vaginatum in herbaria. They have similarities, but can be differentiated mainly by the cauline leaf width, sheath margin and androecium measurements ( Table 1 ). The most similar species of S. iguazuanum is S. marchioides Ravenna (2002: 22) , from which it can be distinguished by the smaller lower valve of the spathes (8.8–15.3 × 0.7–1.8 mm vs. 15.6–27.1 × 2.2–3.3 mm), shorter upper valve (7.8–14.2 mm vs. 17.1–24.4 mm long), shorter pedicel (6.9–14 mm vs. 18–30 mm long), smaller flower (10–12.2 mm vs. 15–20.3 mm in diam.) and tepal size (5.2–6.2 × 2–2.3 mm vs. 7.5–11 × 3.2–5.7 mm) ( Table 1 ).

Another species superficially similar to S. iguazuanum is S. scalarium Ravenna (2002: 26) , described from Chaco and Corrientes ( Argentina), and never recorded in Brazil. They present overlapping measurements such as plant height, stem width and spathes length, but S. scalarium has usually longer and wider leaves (23–45 mm × 2–4.5 mm vs. 11– 20(–25.8) × 1.6–2 mm). A more precise comparison between these two species has not been possible due to the lack of details in the original description of S. scalarium , coupled by the fact that its types and paratypes are unavailable.

Figures

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

FIGURA 6. Habit of Sisyrinchium iguazuanum C.D.Inácio, L.Eggers & Chauveau. From L. Eggers & T.T. Souza-Chies 612 (ICN). Drawing by Anelise Scherer.