Viola longibracteolata P.Gonzáles, Ed.Navarro & J.M.Watson, 2022

Gonzáles, Paúl, Montesinos-Tubée, Daniel B., Watson, John M., Cano, Asunción, Trinidad, Huber, Navarro, Eduardo, Jans, Harry, Sheader, Martin, Ballard, Harvey E. & Flores, Ana R., 2022, Viola ornata and Viola longibracteolata (Violaceae, subgen. Neoandinium), two rare, new rosulate species from southern Peru, Phytotaxa 571 (1), pp. 52-64 : 59-62

2. Viola longibracteolata P.Gonzáles, Ed.Navarro & J.M.Watson , sp. nov. ( Figs. 4 , 5 ).

Type:— PERU. Dpto. Arequipa: Prov. Caylloma, District Madrigal , ladera pedregosa y rocosa, vegetación escasa, pendiente 35°, 15°28’14.15”S, 71°50’21.11”W, 5060 m, 28 April 2016, Navarro 3000 (holotype: USM 326318 !) .

Diagnosis:— It differs from all other species of the section by the combination of linear-spathulate, 5-crenulate leaf blades with exceptionally broad pseudopetioles (1.7–1.9 mm wide), bracteoles 7–7.5 mm long (except with Viola ornata ), sparsely fimbriate sepals, and naviculate inferior petal with an inconspicuous spur. Viola longibracteolata is morphologically similar to V. ornata by the leaf blades with alveolate-reticulate notorious veins and ciliate border, absent stipules and elongate bracteoles, but it differs from this species by linear-spathulate (vs. flabellate), 5-crenate (vs. 11-crenate) leaf blades, plane (vs. 3-winged) bracteoles, and sparsely fimbriate (vs. densely short-ciliate) sepals.

Description:— Perennial acaulous rosulate herb. Rootstock axial, ca. 5 cm × 1.2–1.5 mm. Caudex 5–9 cm long, simple, covered by sclerified leaf scars. Rosette up to ca. 1.5 × 3 cm, densely imbricate-foliate, slightly depressed at centre. Leaves 10–13 mm long, including pseudopetiole, oblanceolate-spathulate, stipules absent. Pseudopetiole 7.4–10.5 × 1.7–1.9 mm, scarious, glabrous on both surfaces and along margin. leaf blade (2.5–)3–3.2 × (2–) 2.4–2.9 mm, obovate-cuneate, thick-succulent; adaxial face alveolate-reticulate, inconspicuously so on leaf blade at centre of rosette, markedly so at outer circumference, cryptic brown, with sparsely scattered white, pilose hairs on basal half, and very few of same towards apex; margin 5-crenate along entire outer margin, brown, scarious, spreading ciliate at margin with short and long, stout, white-hyaline indumentum, hairs ca. 0.2 mm long at apex to 0.7–0.9(–1.2) mm at base, abaxial face glabrescent, green-purple; apex obtuse to rounded. Flowers solitary, axillary, 4–4.8 × 3.1–3.5 mm. Pedicel 7–9 mm long, glabrous, hyaline to dark purple at apex. Bracteoles inserted 0.5(–0.8) mm above base, attached above to pedicel by membrane, free part 7–7.5 × 1–1.5 mm, oblong-oblanceolate, obtuse, hyaline, undersurface pubescent, upper surface glabrescent, margin entire, base glabrous upper half ciliate, with hair decreasing in size towards apex. Calyx green; sepals inconspicuously auriculate at base, auricles rounded, ca. 0.3 × 0.9 mm, glabrous; upper and lateral sepals subequal in size and shape, border slight scarious, 3-nerved, obtuse, inner side glabrous; upper sepal ovate, 1–1.2 × 1–1.1 mm; lateral sepals oblong, 1.5–1.6 × 0.7–0.8 mm; lower sepals oblong, 1.7–1.8 × 0.9–1.2 mm, fimbriate at apex. Corolla glabrous, adaxially white, abaxially dark purple with fine white margin; superior petals 2.9–3.3 × 1 mm, oblong spathulate, 3-nerved; lateral petals 4–4.2 × 1.1 mm, oblong spathulate, 3-nerved, apex rounded-emarginate; inferior petal including spur 4.2–4.5 × 1.4–1.6 mm, oblong spathulate limb, cymbiform, narrowed in middle, 3-nerved, central and basal areas yellow with purple points, apex deeply emarginate; spur ca. 0.7 × 0.7 mm. Stamens ca. 1.3 mm long, winged filament ca. 0.6 × 0.6 mm, anthers ca. 0.7 × 0.8 mm, outer surface glabrous, inferior pair of anthers with nectar spurs, these very slender, ca. 0.6 × 0.1 mm; connective scales ca. 0.4 × 0.6 mm, broadly deltoid, glabrous, margin entire, apex obtuse, color not seen but probably yellow. Ovary glabrous. Style ca. 1.3 mm long, geniculate, clavate. Style crest 0.5–0.7 × 1.1–1.2 mm, apical, subrotund to flabellate. Stigmatic orifice 0.6–0.7 mm diam., apicoventrally in a longitudinal furrow. Capsule 3.7–3.8 × 3.3–3.5 mm, ovoid, glabrous, 3-valved, valve thickened and elevated in middle part; 3 seeds per valve. Seed 1.8–1.9 × 1–1.1 mm, ovoid, dark beige, funiculus adnate to fruit for 0.1–0.2 mm.

Etymology: —An outstanding feature of this new species are the bracteoles 7–7.5 mm long, suggested by specific epithet longibracteolata .

Distribution and habitat:— Viola longibracteolata is endemic to Arequipa Department in Peru, and it is known only from the type location ( Fig. 6 ). It inhabits rocky places and cryoturbated soils (soils that are subjected to a sequence of freezing and thawing throughout the day) above 5000 m. It has probably evaded discovery until now due to its very small size, cryptic appearance and general lack of intensive exploration in the high Andes.

Phenology:— Flowering and fruiting in April.

Conservation assessment:— In accordance with IUCN criteria ( IUCN 2012, 2019) it is proposed that Viola longibracteolata be considered Critically Endangered (CR B1ab(iii)+2ab(iii)). Its extent of occurrence (EOO) and area of occupancy (AOO) are less than 50 km 2 and 4 km 2, respectively (Criterion B1), and it is known from a single location (subcriterion a). Extensive mining exploration in the Madrigal district produces the risk of seriously endangering current and potential suitable mountain summit habitats.As a result, there is continuing reduction in habitat availability and decline in environmental quality (subcriterion b(iii)).

Discussion:— Viola longibracteolata is a distinctive species of Viola subg. Neoandinium . The leaf blade with its alveolate-reticulate, notorious veins and ciliate border indicates that the new species belongs in the large, widespread and polymorphic V. sect. Rosulatae. The extended, plane, bracteoles with long cilia place V. longibracteolata closest to Viola evae W. Becker (1922: 182) , Viola spegazzinii W. Becker (1925: 351) , Viola lilloana W. Becker (1926: 225) , and the other new species described herein, V. ornata . The latter two also share the distinctly small corollas with V. longibracteolata . However, Viola ornata differs from other V. sect. Rosulatae species by its 3-winged (vs. plane) bracteoles; V. spegazzinii and V. lilloana differ from this species group by its glandular (vs. eglandular) leaf blade undersurface, while V. longibracteolata differs from these species by the sparsely fimbriate sepals. On the other hand, V. longibracteolata differs from V. evae by its peduncle bracteoles 7–7.5 mm (vs. 4 mm) long.

Viola longibracteolata and V. ornata very morphologically similar due to their glabrous or glabrescent leaf blades, elongated bracteoles, glabrous pedicels, eglandular sepals, and glabrous corolla, but the former is differentiated from the latter by its linear-spathulate (vs. flabellate), 5-crenate (vs. 11-crenate) leaf blades, long-ciliate (vs. fine short-ciliate) margins, plane (vs. 3-winged) bracteoles, sparsely fimbriate (vs. densely short-ciliate) sepals, corolla 3–4.8 mm vs. 6–7 mm long, inferior petal spur ca. 0.7 mm vs. 3.5 mm long, and style crest 0.5–0.7 mm vs. 0.35 mm long. Moreover, Viola longibracteolata and V. ornata are geographically separated by over 130 km in high Peruvian Andes.

Figures

FIGURE 4. Viola longibracteolata. A. Leaf from centre of rosette (adaxial view). B. Leaf from centre of rosette (abaxial view). C. Leaf from outer circumference of rosette (adaxial view). D. Leaf from outer circumference of rosette (abaxial view). E. Bracteole. F. Upper sepal. G. Superior petals. H. Lateral petals. I. Inferior petal. J. Gynoecium with apical style crest. K. Inferior stamen, showing connective scale and nectar spur. L. Capsule. M. Seed (side view).

FIGURE 5. Viola longibracteolata. A. Habit. B. Top view of flower, showing inner lower petals and reverse of upper petals. C. Side view of flower showing abaxial surface of superior and lateral petals. D. Top view of flower, showing inner petals. Photos by E. Navarro.

FIGURE 6. Distribution map of Viola ornata and Viola longibracteolata.