Sisyrinchium usneoides C.D.Inácio & K.Antunes, 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 : 158-161

Sisyrinchium usneoides C.D.Inácio & K.Antunes , sp. nov. ( Figs. 4 and 5 )

Diagnosis:— Sisyrinchium usneoides differs from related species by the numerous, narrow, falcate to arcuate cauline leaves (0.3–0.5 mm wide), arranged close to one another, with angle between leaves and stem of 30−70 degrees, papillose leaf sheaths, peduncles 2.5−8 mm long and pedicels 5−6 mm long.

Type:— BRAZIL. Minas Gerais: Santa Rita de Jacutinga , 31 July 1970 (fl, fr), P. L. Krieger & C. Urbano 9020 (holotype SPF!, isotypes CESJ!, ICN!) .

Perennial herb, erect, 23–39 cm tall. Rhizome short, roots fibrous and slightly thickened. Basal leaves absent. Cauline leaves, numerous, plane, falcate to arcuate, 7.5−11.7 × 0.3–0.5 mm, glabrous, attenuate, margin entire, sheath 2−4 mm long, papillose, margin entire.Angle between leaves and stem 30−70 degrees. Stem narrowly winged, branched, 22−38 × 0.04−0.16 cm, internodes 1.7−5 mm long. Inflorescence axillary and terminal. Rhipidium 1-flowered, pedunculate, peduncle 2.5−8 mm long. Spathes bivalved, lower valve 6.5−9.3 × 1−1.2 mm, upper 8−9.3 × 1.2−1.3 mm, glabrous, attenuate to acuminate, membranaceous margin on both valves. Pedicel shorter than spathes, 5−6 mm long, glabrous. Perigon disk-shaped, yellow, 11.5 mm in diam. (measurement from spirit-preserved flowers). Tepals subequal, 5.8 × 2.2 mm, free, oblanceolate, attenuate-acuminate, concolorous, glabrous. Filaments yellow, basally connate for 1 mm, then 0.6 mm free, ascending to patent, glabrous. Anthers yellow, versatile, 2.5 mm long. Ovary obovoid, 1.2 × 0.9 mm, glabrous. Style yellow, 1 mm long, style branches 1 mm long, alternate to the stamens, ascending to patent. Capsule subglobose, 4.5 × 5 mm, dark yellow-green to dark brown, glabrous. Seeds not seen.

Distribution and Habitat:—The species was only found in the municipality of Santa Rita de Jacutinga, southern Minas Gerais, in a location in the Área de Proteção Ambiental Boqueirão da Mira, part of the Serra da Mantiqueira , in the Atlantic Forest biome, Brazil ( Fig. 3 ). It grows at an elevation of about 1400 m, in campo rupestre phytophysiognomy. Vegetation in the sampled area is characterized by predominance of an herbaceous layer with sparse shrubs. The species grows in sandy soils where the watertable is high, allowing longer waterlogging periods, with colonization by wetland species, and forming peat bogs with Sphagnum L. and other species of Iridaceae , Cyperaceae , Droseraceae , Lentibulariaceae , Melastomataceae and Xyridaceae .

Phenology: —Flowers and fruits were observed in July and November.

Conservation Status: —Critically Endangered (CR, B2ab(iii)) according to the IUCN Red List guidelines ( IUCN 2019). It is known from few locations, with a small area of occupancy (AOO <5 km 2). Although the species occurs inside a conservation unit, the Área de Proteção Ambiental Boqueirão da Mira in the Serra da Água Santa, this location is registered for future mining purposes in the DNPM (National Department of Mineral Production) System ( Carvalho 2019). Species population size, number of mature individuals and demographic resilience are unknown.

Etymology: —The species epithet is a reference to the general appearance of the vegetative parts of the plant that resemble the habit of lichens of the genus Usnea Dill. ex Adans. , as well as the bromeliad Tillandsia usneoides (L.) L..

Paratypes: — BRAZIL. Minas Gerais: Santa Rita de Jacutinga, APA Boqueirão da Mira , Serra da Água Santa, 13 November 2018 (fl, fr), K. Antunes et al. 931 (CESJ!, ICN!) .

Taxonomic relationships:— Sisyrinchium usneoides has particular characteristics such as the very narrow (0.3– 0.5 mm wide), falcate to arcuate cauline leaves, papillose sheath surface, numerous cauline leaves distant 30 to 70 degrees from the stem, short internodes, short peduncles (2.5–8 mm long) and pedicels (5–6 mm long). The most similar species is S. vaginatum , but S. usneoides is distinguished by the above mentioned features as well as by its leaf sheaths with entire margin (vs. ciliate), flowers with shorter free filaments (0.6 mm vs. 0.7–1.2 mm long), shorter style branches (1 mm vs. 1.4–1.8 mm long), and wider fruits (5 mm vs. 3.1–4.5 mm wide) ( Table 1 ).

Other species with cauline leaves occur in the state of Minas Gerais but all of them show wider leaves. Sisyrinchium itabiritense Ravenna (1981: 4) , together with S. vaginatum , are the species with narrower leaves, but measurements are larger than those of S. usneoides . Moreover, S. itabiritense has basal leaves and rose-lilac (rather than yellow) flowers ( Ravenna, 1981).

Figures

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

FIGURE 4. Habit of Sisyrinchium usneoides C.D.Inácio & K.Antunes. From P.L. Krieger & C. Urbano 9020 (SPF). Drawing by Rafaella Marchioretto.

FIGURE 5. Sisyrinchium usneoides C.D.Inácio & K.Antunes. A–B. Stem with flowers and fruits. C. Flower in frontal view. D. Fruits. E. Individuals of S. usneoides (yellow arrows) in a grassland with Xyris sp. (blue arrows). F. Habitat in campo rupestre, Minas Gerais, Brazil. From K. Antunes et al. 931 (CESJ).