Viola ornata P.Gonzáles, Montesinos & 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 : 54-55

1. Viola ornata P.Gonzáles, Montesinos & J.M.Watson , sp. nov. ( Figs. 1 , 2 , 3 ).

Type:— PERU. Dept. Moquegua: Prov. Sánchez Cerro, District of Ichuña, Sora , ladera con suelo crioturbado, franco-arcilloso, hierba escasa, tallos parcialmente subterraneo, hojas de coloración créptica entre marrón claro y anaranjado, flores liláceas. 16°13’26.91’’S, 70°32’23.70’’W, 4710–4790 m, 22 October 2010, Cano et al. 19929 (holotype: USM 329556 !) .

Diagnosis:— It differs uniquely from all others species of Viola sect. Rosulatae by densely adpressed-imbricate foliage, widely flabellate leaf blade with obtuse-depressed apices, exceptionally broad (ca. 3 mm wide) pseudopetioles, long (ca. 9 mm) bracteoles, and naviculate inferior petal with retrorse spur. The most morphologically similar species to V. ornata is V. congesta by the flabellate, 11-crenate, glabrous leaf blades, with finely short-ciliate margins. The new species differs from V. congesta mainly by its eglandular (vs. glandular) leaf blades, absent (vs. present) stipules, 3-winged (vs. plane) bracteoles, and trilobed (vs. entire) style crest.

Description:— Perennial, evergreen, dwarf, acaulous, imbricate-rosulate herb, habitually forming solitary rosettes, but occasionally up to six. Rootstock axial, medium-thick, prolonged, giving rise to short, usually unbranched caudex, this ca. 1.5 mm wide at junction with rosette. Rosette ca. 2 × 2.5 cm, approximately hemispherical. Foliage spirally arranged, dense, light brown. Mature leaf ca. 1.5 cm long, stipules absent, pseudopetiolate, spathulate-flabellate; pseudopetiole 8 × 3 mm, glabrous, thickish-succulent longitudinally along centre, thin at margins; leaf blade ca. 4 × 8 mm, somewhat thick-succulent, subtriangular-flabellate, 11-crenate along entire outer margin, that narrowly glossy-thickened and regularly short-ciliate; upper surface of leaf blade glabrous, raised reticulate-alveolate veined; undersurface of leaf blade glabrous except apically, where it is sometimes densely covered with minute, translucent white papillae. Flower ca. 5 × 7–8 mm, solitary, axillary, corolla flush with outer circumference of rosette, anthesis successive. Pedicel ca. 1 cm long, glabrous, expanding towards apex. Bracteoles inserted ca. 4 mm above base of pedicel, 9 × 1.5 mm, linear oblanceolate, hyaline, 3-winged in section, with central wing situated on abaxial face, apex rounded, all three margins ciliate in apical half, Calyx ca. 3.5 mm long; sepals unequal, broadly sublinear with rounded apex, hyaline, regularly short-ciliate. Corolla glabrous, white; superior petal ca. 7 × 2 mm, linear-subspathulate, slightly upcurved laterally, somewhat truncate; lateral petal ca. 6 × 2.5 mm, spathulate, rounded apically; inferior petal (including spur) ca. 7 × 2.5 mm, sublinear, strongly navicular with curved, rounded keel, stained yellow longitudinally along centre, apex emarginate. Spur ca. 3.5 × 1 mm, flattened dorsally, strongly retrorse, somewhat upcurved towards keel of lowermost petal, apically subretuse. Stamens ca. 1.8 mm long, winged filament ca. 0.5 × 0.5 mm, anthers ca. 0.7 × 0.8 mm, outer surface glabrous, inferior pair of anthers with nectar spurs, these very slender, ca. 1 × 0.1 mm; connective scales ca. 1 × 0.9 mm, broadly deltoid, glabrous, margin entire, apex obtuse, bright brownish-red; Ovary glabrous, distinctively ribbed. Style bigeniculate (‘S’ form), markedly clavate at apex. Style crest as vertical lateral lobes ca. 0.35 × 0.5 mm, triangular, apically rounded. Stigma frontal, elevated. Fruit and seeds unknown.

Etymology:— An outstanding feature of the new species is the formally geometrical and intricately patterned nature of its leaves and rosette.The epithet ornata was chosen in reference to the neat and attractive aesthetic appearence of these plants.

Distribution and habitat:— Viola ornata is a narrow endemic to the Moquegua Region in Peru, at elevations of 4650–4970 m on the peaks of the eastern mountain summits of the Upper Tambo River near Tassa Town ( Fig. 6 ). A terrestrial plant of sandy volcanic soils and, more rarely, clayey rocky terrain, it forms an element of a dwarf Andean flora.

Phenology:— The new species flowers in October.

Additional material examined (paratypes):— PERU. Dept. Moquegua: Prov. General Sánchez Cerro, District of Ichuña , Sora , ladera con suelo crioturbado, franco-arcilloso, 16°13’26.91’’S, 70°32’23.70’’W, 4710–4790 m, 22 October 2010, Cano et al. 19930 ( USM 329557 !) . District of Ubinas, terrestrial on bare clay soils in roadside verges to the east of Pillone town, 16°10’02”S, 70°49’56”W, 4584 m, 24 March 2013, Montesinos 4022 ( HSP, USM) . Ubinas, lower slopes of the Pirhuani Mountain close to Cochapata Lake , 5km S of Coalaque town , 4km N of Tassa town, 16°8’30.53”S, 70°42’52.86”W, 4700 m, 20 March 2014, Montesinos 4217b ( HSP) . District of Yunga, lower slopes of the Chocho-Choco Mountain, near Siliaca Alta , 5km NW of Matecocha Lake and 7km E of Yunga town, 16°13’12.16”S, 70°36’35.23”W, 4970 m, 16 August 2019, Montesinos 7706 ( MOQ) . Yunga, Pucapampa , between Siliaca Alta and Choco-Choco, 16°13’34.83”S, 70°36’18.85”W, 4854 m, 18 February 2021, Montesinos et al. 8518 ( MOQ 1170 !) .

Estimated Conservation status:— In accordance with IUCN criteria ( IUCN 2012, 2019) it is proposed that Viola ornata be considered Endangered (EN B1ab(iii)+2ab(iii)). The Extent of occurrence (EOO) and area of occupancy (AOO) are less than 104 km 2 and 20 km 2, respectively (Criterion B1 and B2), and the populations are severely fragmented (subcriterion a). Extensive mining exploration in the Ichuña district produces the risk of seriously endangering current and potential suitable mountain summit habitats, thus there is continuing decline in habitat quality (subcriterion b(iii)).

Discussion

Viola ornata is a distinct species of Viola subg. Neoandinium with few morphologically similar species. The reticulate, notorious veins and ciliate border of the leaf blade indicate that the new species belongs in the large, widespread and polymorphic Viola sect. Rosulatae , the general morphology of the rosette of the novelty is closely similar to a few others in that alliance. They are Viola volcanica Gilles ex Hooker & Arnott (1833: 145) , Viola congesta Gilles ex Hooker & Arnott (1833: 144) , and Viola llullaillacoensis W. Becker (1927: 109) , all from northern Chile. Viola ornata is similar to V. llullaillacoensis and V. volcanica by its reticulate-veined leaf blades with ciliate margin, but it differs from V. llullaillacoensis by the glabrous (vs. pilose) upper leaf blade surface, and eglandular vs. glandular leaf blades. From V. volcanica it differs by eglandular vs. glandular leaf blades and ciliate vs. glabrous calyx. On the other hand, V. ornata is similar to V. congesta by its flabellate, 11-crenate, glabrous leaf blade, with the margin fine short-ciliate, but it differs by its eglandular vs. glandular leaf blade, absent vs. present stipules, bracteoles ca. 9 mm vs. ca. 3 mm long, 3-winged vs. plane, densely short-ciliate vs. glabrous sepals, glabrous vs. bearded lateral petals, and trilobed vs. entire style crest.

There are 15 tropical Andean species of Viola subg. Neoandinium , most of which are found in Peru, where they encompass an exceptionally diverse morphology. Among these species, the most similar to V. ornata is Viola kermesina W. Becker (1909: 124) , with which it shares rosettes with broad, strongly and tightly imbricate leaf blades with similar venation. However, while the new species has white corollas, and crenate and cryptic brown leaves, V. kermesina has red, crimson or orange corollas, and entire and superficially grey leaves. Other three taxa with similarly cryptic rosette coloration, Viola ferreyrae P. Gonzáles ( Gonzáles & Cano 2016: 84) , Viola tovarii P. Gonzáles & J. Molina Alor (2020: 248) , and Viola granulosa Weddell (1864: 292) have leaf blades deeply incised along the margins, among other dissimilarities (see key).

Figures

FIGURE 1. Viola ornata. A. Mature rosette from above. B. Leaf (adaxial view). C. Detail of the hyaline ciliate hairs on leaf margins. D. Leaf (abaxial view). E. Pedicel and flower. F. Dissection of calyx showing sepals: superior sepal central. G. Detail of marginal cilium. H. Bracteole, showing three ciliate wings. I. Bracteoles cross sections (basal and apical). J. Upper view of inferior petal. K. Side view of the inferior petal showing retrorse spur. L. Lateral petal. M. Superior petal. N. Front view of style head. O. Style head and crest at tip of geniculate style branch above ovary. P. Inferior stamen with slender nectar spur and connective scale above.

FIGURE 2. Viola ornata. A. Habitat in the mountain summits near Yunga Town (elev. 4970 m). B. Solitary rosettes. C. Details of flowering. D. Details of leaf (adaxial view) showing ciliate margin. Photos: A and D by D.B. Montesinos; B and C by H. Trinidad.

FIGURE 3. A. Solitary rosettes of Viola ornata in the mountain summits near Tassa Town (elev. 4705 m). B. Multiple rosettes with detail of the flowers of Viola ornata in the mountain summits near Ichuña. 4790 m. Photos: A by M. Sheader; B by H. Trinidad.

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