Brayopsis arequipa Al-Shehbaz, Cano, M. Cueva & Salariato, 2022

Cano, Asunción, Manchego, Marco Antonio Cueva, Salariato, Diego L. & Alshehbaz, Ihsan A., 2022, Brayopsis arequipa, a new species from South Peru (Brassicaceae), Phytotaxa 559 (2), pp. 217-220 : 217-219

Brayopsis arequipa Al-Shehbaz, Cano, M. Cueva & Salariato , sp. nov.

Diagnosis:—The species differs from its closest relatives by having reticulate seeds, linear, smooth fruits to 7 mm long, 20−30 ovule per ovary, purple flowers, and leaves longer than to subequaling the length of fruits plus fruiting pedicels.

Type:— PERU. Dpto. Arequipa, Prov. Condesuyos, Distr. Cayarani, alrededores de la Laguna Tintarcocha-Poracota, 30 km de Orcopampa, entre rocas, 15°13’52.34”S, 72°30’46.22”W, 4827 m, 31 January 2013, M. Cueva & B. Oblitas G. 1963 (holotype, USM; isotype, MO-6701109). Figures 1 , 2 .

Description:— Herbs perennial, minutely puberulent on leaves, not pulvinate, sometimes forming compact rosettes with thick, many-branched main roots; caudex very short, simple or few branched, covered with petiolar remains of previous years. Trichomes 0.01−0.25 mm long. Basal leaves rosulate; petiole slender, glabrous or minutely ciliate, 5−15 mm long, broadly flattened, becoming papery at base, usually distinctly longer than blade; leaf blade orbicular, 4−6 × 3−5 mm, sparsely puberulent adaxially, glabrous abaxially, base obtuse to cuneate, margin entire, apex rounded to obtuse. Fruiting pedicels solitary, erect to ascending, 5−10 mm long. Sepals oblong, caducous shortly after anthesis, 1.5−2 mm long; petals purple, oblanceolate, 1.5−2 × ca. 1 mm, base cuneate, apex obtuse; filaments 1−1.3 mm long; anthers ovate, ca. 0.3 mm long; ovules 20−30 per ovary. Fruit linear, straight, 5−7.5 × 1.8−2 mm; valves glabrous, smooth; septum complete; gynophore absent; style obsolete or to 0.1 mm long. Seeds brown, ovoid, pendulous, reticulate, 1.2−1.5 × 0.8−0.9 mm.

Phenology: —flowering and fruiting in January.

Habitat: —between rocks; 4700-4900 m.

Distribution: —Endemic to Arequipa, Peru.

Etymology: —The species epithet arequipa is named after the Peruvian department Arequipa. It is a noun used in apposition and, therefore, should be maintained according to Article 23.5 of the International Code of Nomenclature for Algae, Fungi and Plants ( Turland et al., 2018).

Additional specimens examnined (paratypes): — PERU. Dpto. Arequipa, Prov. Condesuyos , Distr. Cayarani, alrededores de la Laguna Tintarcocha , Borde de bofedal, 15°13’53.25”S, 72°30’26.32”W, 4725 m, 31 January 2013, M. Cueva & B. Oblitas G. 1969 ( MO, USM) .

Discussion: — Brayopsis arequipa most closely resembles B. cuscoensis Al-Shehbaz et al. (2018: 214) , which grows in neighboring Cusco Department with similar habitats and cryoturbated soils, by having reticulate seeds, similar trichome distribution and size, obsolete styles or to 1 mm long, and orbicular leaf blades much shorter than the basally flattened petioles that become papery. It differs, however, by having linear, non-torulose fruits 1.8−2 mm wide and 20−30 ovules per ovary. By contrast, B. cuscoensis has oblong, torulose fruits 3−3.3 mm wide, and 10−14 ovules per ovary. It is easily distinguished from all Brayopsis species except the latter, for which flower color has not yet been recorded, by having purple instead of white or creamy white petals. It differs from the other related close congeners B. calycina (Desv.) Gilg & Muschler (1909: 484) , the generic type, and B. monimocalyx Schulz (1924: 241) by having orbicular (vs. with linear to narrowly oblong) leaf blades, leaves subequaling to longer (vs. shorter) than the length of fruits plus fruiting pedicels, and ovoid (vs. oblong), reticulate (vs. smooth) seeds. It further differs from B. calycina , the most variable and widespread species of the genus ( Argentina [Catamarca, Jujuy, Salta, Tucumán], Bolivia [La Paz, Potosí, Tarija], and Peru [Ancash, Apurimac, Arequipa, Ayacucho, Cajamarca, Cuzco, Huancavelica, Junín, Lima, Moquegua, Puno, Tacna]), by having slightly shorter petals (1.5−2 vs. 2−4.5) mm and fruits (5−7.5 vs. 8−17) mm, and from B. monimocalyx O.E. Schulz ( Argentina [Jujuy, La Rioja, Salta], Bolivia [La Paz, Cochabamba], Chile [Región de Arica y Parinacota], Peru [Moquegua, Puno)] by having caducous (vs. persistent) sepals.

Figures

FIGURE 1. Brayopsis arequipa. A. Plant. B. Fruit. C. Seed. Drawn by Al-Shehbaz from isotype (Cueva & Oblitas 1963, MO-6701109).

FIGURE 2. Brayopsis arequipa. A, B. Plants in flower. C. Plant with dehisced fruits. Photos by Marco Cueva from plants of Arequipa.