Herbertia guyunusae Deble, 2022

Deble, Leonardo Paz, 2022, Herbertia guyunusae, a new species of Iridaceae from the grassland ecosystem of Río de La Plata, South America, Phytotaxa 570 (1), pp. 55-66 : 56-59

Herbertia guyunusae Deble , sp. nov. ( Figs. 1 , 2 , 3 and 4G )

Diagnosis:— Herbertia guyunusae is distinguished from H. crosae by its outer tepals porcelain dark-violet colored (vs. pallid lilac), with one-celled lipidic trichomes scattered near at the base of the blade (vs. one-celled lipidic trichomes abundant, forming a triangular carpet along the claw and ending near at the base of the blade), by its oblong inner tepals, with 8–9 × 2–3 mm (vs. spathulate or elliptic, 5-6 × 2–3 mm), by its stamens with filaments united for 7–9 mm long and apically free for 2–3.5 mm (vs. united for 4–5 mm long and free apically for 1–1.5 mm), and by its bigger anthers, 5–6 mm long (vs. 4–5 mm long). Herbertia guyunusae differs from H. quareimana by its delicate habit (vs. robust), reaching 8–15 cm in height (vs. 15–35 cm in height), by its narrowly linear leaves, 7–16 × 0.1–0.2 cm (vs. linear-lanceolate or elliptic-lanceolate, 12–35 × 0.6–1.5 cm), by its smaller spathes, with 2.2–3.4 × 0.2–0.4 (vs. 4.4–6 × 0.4–0.8), by its smaller flowers, 3–4 cm diam. (vs. 6–7 cm diam.), and by its inner oblong tepals, with 8–9 × 2–3 mm (vs. ovate, ovate-lanceolate or elliptic-lanceolate, 12–16 × 5–6 mm).

Type:— BRAZIL. Rio Grande do Sul: São Gabriel, RS 473, Cerro do Ouro , campo com solo raso, sobre rochas, 7 November 2019, L.P. Deble & B.P. Moreira 19622 (holotype PACA!, isotypes ICN, SI) .

Geophyte up to 8–15 cm high above the soil, underground stem up to 7 cm long. Bulb nearly ovate, 10–25 × 9–20 mm wide, prolonged in a collar up to 6 cm. Basal leaves up to 8, green at anthesis; blades narrowly linear, plicate, acute at apex, 7–16 × 0.1–0.2 cm. Flowering stem cylindrical, proximally foliose, unbranched or 2–branched. Caulinar leaf bracteose, 1.5–2.8 × 0.2–0.3 cm, concealing the peduncles of spathes. Spathes 1–2 per branch, fusiform, 2.2–3.4 × 0.2–0.4 cm, herbaceous, pallid-green, bivalved, two-flowered, pedunculate, peduncles 1–4 cm long; lower valve 1.2–2 cm long, the upper 2.2–3.4 cm long, both with membranous edges, at apex reddish-brown or brown, with purple parallel veins; pedicel filiform, 2–4 cm long. Flowers predominately porcelain dark-violet and whitish proximally, radially symmetrical, 3–4 cm diameter. Tepals whorls sharply dissimilar: outer tepals obovate-oblong, pandurate, 18–24 × 9–12 mm, lipidic trichomes scattered; blade obovate or obovate-oblong, dark-violet, 13–17 × 9–12 mm; claws broadly cuneate, 5–7 × 4–5 mm, opaline-white, densely covered by dark-blue stripes and dots; inner tepals oblong, 8–9 × 2–3 mm, violet, base purplish-violet, apex long attenuate, obtuse, slightly reflexed, central concavity with a transverse medial stripe yellow and purple spotted, which extending at the margin of the blade, one-celled lipidic trichomes abundant covering the central concavity. Filaments united for 7–9 mm long in a bottle shaped column and apically free for 2–3.5 mm; column straw-colored or pallid violet with purple stripes, and purple near at the base; anthers linear, yellow, curved at dehiscence, 5–6 mm long; locules yellowish, pollen yellow. Ovary obovate-clavate, 4–6 × 2.5–3.5 mm. Unbranched part of style 7–10 mm long. Style branches channeled, 3.5–4 mm long, at the apex bifid for 1.5–1.8 mm, the divisions divergent, recurved, facing down, and apically stigmatic. Capsules nearly spherical or broadly clavate, 6–11 × 4.5–6 mm. Seeds oblong to obconical, angular, reddish-brown, epidermis striate, foveolate, 0.8–1.4 mm long.

Eponym: —The delicacy of the flowers of Herbertia guyunusae lead me to propose the specific epithet guyunusae , which pays a tribute to María Micaela Guyunusa (1806–1834). Guyunusa was one of the last Charrúa women; she was born in Paysandú and was one of the four Charrúas sent by Francois de Curel to France. She died in Lyon in the year 1834 ( Rivet 1930, Asenjo 2007).

Specimens examined (paratypes): — BRAZIL. Rio Grande do Sul: Bagé, Joca Tavares , 17 October 2008, L.P. Deble & al. 11017 ( PACA) . Dom Pedrito, Torquato Severo : 28 October 2019, L. P. Deble & B.P. Moreira 19641 ( ICN, PACA, SI) . Lavras do Sul, Ibaré , 31 October 2009, L.P. Deble & al. 11344 ( PACA) . São Gabriel , RS 473, 1 km após a bifurcação das Três Estradas, 4 November 2020, L.P. Deble & B.P. Moreira 19703 ( ICN, PACA, SI) .

Phenology: —Specimens with flowers and fruits can be found during October and November. The flowers open only one day, in the morning, withering early afternoon. On cloudy days the flowers remain opened up to the middle afternoon.

Distribution and habitat: — Herbertia guyunusae was found in Bagé, Dom Pedrito, Lavras do Sul, São Gabriel, and Santa Margarida do Sul municipalities, in south-central Rio Grande do Sul state, Brazil. The plants prosper in small areas of grasslands developed under shallow soils, in mosaic with drier sites and often with rocky outcrops of different origins, but mainly granitic rocks from Santa Maria formation, associations of granites and metamorphic rocks, and volcanoclastic rocks from Acampamento Velho formation ( Sommer et al. 2011), located in the Campos region of the grassland ecosystem of Río de La Plata, the most extensive grassland region to the Southeast South American Grasslands (SESA Grasslands, sensu Azpiroz et al. 2012). These environments are rich in diversity, occurring several species, among them prosper many rare and threatened as Calibrachoa pubescens ( Sprengel 1825: 615) Stehmann in Stehmann & Bohls (2007: 240), Clara gracilis Lopes & Andreata (2006: 298) , Heterothalamus rupestris Deble et al. (2003: 1) , and several endemic Cactaceae of the genera Frailea Britton & Rose (1922: 208) and Parodia Spegazzini (1923: 70) . The new species grows together with Cicendia quadrangularis ( Lamarck 1786: 645) Grisebach (1838: 157) , Gamochaeta stachydifolia ( Lamarck 1786: 757) Cabrera (1961: 382) , Hypericum polyanthemum Klotzsch ex Reichardt (1878: 189) , Rhynchospora tenuis Link in Sprengel et al. (1820: 76), Scoparia ericacea Chamisso & Schlechtendal (1827: 603) , and Scoparia montevidensis ( Sprengel 1825: 42) Fries (1907: 22) , In the same environments of occurrence of Herbertia guyunusae many others bulbous were registered, including the Iridaceae Cypella pusilla ( Link & Otto 1828: 125) Jackson (1893: 689) , and Kelissa brasiliensis ( Baker 1877: 134) Ravenna (1981: 106) , and several Amaryllidaceae , among them Beauverdia dyalistemon ( Guaglianone 1971: 800) Sassone & Guaglianone in Sassone et al. (2014: 774), B. hirtella ( Kunth 1843: 465) Herter (1943: 509) subsp. glabrata Deble (2021a: 22) , B. vittata ( Grisebach 1879: 318) Herter (1943: 511) , and Nothoscordum collinum Ravenna (1989a: 41) . Herbertia caerulea , H. lahue and H. pulchella were registered in nearby areas, but not occur in the same places of H. guyunusae .

Conservation: — Herbertia guyunusae is known only by ten localities, and all known populations contain few individuals. The populations spread in an extension of occurrence of 1,093 km ² and area of occupancy of 40 km ². The species occurs in specific habitat, as it only grows on humid rocky grasslands, mainly volcanoclastic rocks and granitic rocks, and the bulbs developed just above the rocks or in rocky concavities. These environments are being modified by economic activities, as mining and agriculture. The mining activities and the invasion of exotic species in the region of occurrence of Herbertia guyunusae , notably “capim-anonni-2” ( Eragrostis plana Nees von Esenbeck 1841: 390 ), an exotic invasive species native from Africa, result in a direct threat to this taxon. In accordance with the criteria of IUCN (2019), Herbertia guyunusae can be considered Endangered (EN), based in direct threat, geographic distribution, occupation area and population size [EN B1+B2bc (i, ii, iii, iv) + c (iii, iv) + C1+C2a (i), b].

Discussion: — Herbertia guyunusae is easily recognized by its narrowly linear leaves, smaller spathes, and flowers with perigone porcelain dark violet, having inner tepals oblong, slightly reflexed and obtuse at apex and with central concavity containing a transverse medial stripe yellow and purple spotted, which extending to the margin of the blade, and stamens with filaments free apically. Even with several distinctive features, Herbertia guyunusae can be confused with H. crosae by its similar vegetative aspect and with H. quareimana by its perigone morphology. However, Herbertia guyunusae differs from Herbertia crosae by its outer tepals porcelain dark-violet colored, with one-celled lipidic trichomes scattered near at the base of the blade, by its inner tepals oblong, and stamens with filaments longer and by its bigger anthers. Herbertia guyunusae promptly differs from H. quareimana by its delicate habit, by its narrowly linear leaves, shorter spathes, much smaller flowers, and narrower and oblong inner tepals.

Herbertia guyunusae easily differs in several aspects from H. amatorum , H. pulchella and H. zebrina , the other three species that have filaments free apically. H. amatorum and H. pulchella display more robust habit, wider leaves, larger spathes and bigger flowers, and outer tepals with one-celled lipidic trichomes abundant, forming a heart-shaped area along the claw and ending near at the base of the blade. H. zebrina readily distinguishes to H. guyunusae by its white perigone, by its outer tepals with one-celled lipidic trichomes abundant, forming a narrowly triangular carpet along the claw and ending near at the base of the blade, by its inner tepals broadly spathulate, white and purple striped, and rounded or truncate apex, and by its smaller anthers. Additional morphological characteristics and measurement information can be accessed in the Table 1 .

Figures

FIGURE 1. Herbertia guyunusae. A–B. Habit. C. Flower, upper view. D. Flower, lateral view, evidencing spathes and distal part of peduncles. E. Flower, showing style, stamens, and inner bract. F. Capsule. G. seeds. H. Caulinar leaf and proximal part of peduncles. I. Spathes in fruiting (A, C–E, H, from L. P. Deble & B.P. Moreira 19622, B, F, G, I, from L.P. Deble & B.P. Moreira 19703).

FIGURE 2. Map of geographic distribution of Herbertia guyunusae. Orange circles represent specimens collected, gray circles represent specimens observed, which were not made vouchers.

FIGURE 3. Herbertia guyunusae. A–B. Habit. C. Flower, inclined view. D. Flower, lateral view E. Flower, showing style, stamens, and two inner bracts. F. Inner tepal, lateral view. G. Inner tepal, frontal view H. Flower, upper view, showing the style branches, inner tepals and claws of outer tepals. I. Capsule. J. Seeds (A, from L.P. Deble & B.P. Moreira 19622, B, I–J, from L.P. Deble & B.P. Moreira 19703, C–D, from material non collected, E–H from material cultivated of the same population of the holotype).

FIGURE 4. Diversity of Herbertia. A. Herbertia amabilis. B. Herbertia amatorum. C. Herbertia amoena. D. Herbertia caerulea. E. Herbertia crosae. F. Herbertia darwinii. G. Herbertia guyunusae. H. Herbertia lahue. I. Herbertia pulchella. J. Herbertia quareimana. K. Herbertia tigridioides. L. Herbertia zebrina. (Scale bar in L = 1 cm).