Weberbauerella chilensis Faúndez & Saldivia, 2014

Weberbauerella chilensis Faúndez & Saldivia View in CoL , sp. nov. ( Fig. 1–2 View FIGURE 1 View FIGURE 2 )

Haec species W. brognartioides similaris , sed differ per suam minoris formae (10–15 non 25–30 cm), prostratus non erecti habitus; paria foliolis minus (7–12 non 17–20); forma foliolis (linearibus-ellipticis, non ovalibus) et apicem mucronatus, non truncatus vel emarginatus.

Type: — CHILE. Tarapacá: Comuna de Pica, Camino a Salar del Huasco , 3600 m, 31 March 2008, L. Faúndez & B. Larraín s.n. (holotype SGO 162972 ! , isotypes SGO 162973 ! , CONC 177641 ! ).

Herbaceous perennial, ephemeral. Tubers deep underground, one or several, spherical or oval, blackish brown, 2–4 × 2–4 cm. Plant prostrate, notably branched from the base, 10–15 cm high, 30 cm in diameter; branches zigzag, up to 15 cm long, smooth, densely sericeous-pubescent, with scattered dark glands, internodes 15–20 mm long in mature branches. Leaves imparipinnate; stipules caducous, linear-lanceolate, 4–5 mm long, 0.7 wide at the base, white-hairy with hairs to 1mm long, abaxial side also covered with scattered dark pustular glands; petioles 0.5–1 cm long, base and adaxial side densely covered with up to 0.5 mm long white hairs; leaflets 7–12 pairs, terminal leaflet caducous, 1–1.7 cm long, 5–7 mm wide, linear-elliptic, base obtuse, margin entire, apex acute, shortly mucronate, glandular, adaxial surface eglandular, pubescent, abaxial surface with sparse pubescence, numerous flat to depressed glands, 0.5 mm long whitish hairs. Inflorescence a raceme, 2–5-flowered; rachis 2–3 cm long. Flowers zygomorphic, papilionoid, 13–18 mm long; pedicel 5–10 mm long. Calyx strongly bilabiate, glandular, pubescent with trichomes short, antrorse, whitish; upper lip bilobed, lobes 4 × 3.5 mm, oblong, apex rounded; lower lip threelobed, lobes 5 × 1.5 mm, linear-lanceolate, apex of lateral lobes acuminate, apex of central lobe acute to obtuse. Standard petal, 15 × 15 mm, base unguiculate, yellow-green, intermediate zone purplish, margin whitish, nerves dichotomously branching toward the margin or occasionally anastomosing, pustular glands slightly convex, brownish, concentrated and larger towards the base; wing petals, 10 × 8 mm, slightly obovate, base auriculate, unguiculate, apex obtuse, white-purple, internerves with grooves on the lower half, pustular glands few and scattered; keel 16 × 8 mm, claw 2 mm long, base strongly auriculate, auricle 1.5 mm long, slightly unguiculate, inner margin irregularly notched, apex obtuse, whitish, the outer face with numerous prominent glands. Stamens 10, filaments united in basal half, 16–18 mm long, 15 mm wide, glabrous; anthers 1.3 mm long. Gynoecium 20 mm long, base stipitate, ovary moniliform, slightly arched upwards, 11 × 0.7 mm at the seminal portion, 0.3 mm wide between the ovules, 4–6 septate, margin hairy, seminal portion glandular, style 9 mm long, cylindrical, glabrous, stigma punctiform. Legume shortly pedunculate, 15–16 mm long not including the remains of the style, articles 4– 6 (2-3 with complete development and the remaining underdeveloped), 4–6 × 4 mm, circular to elliptic, margin slightly hairy, conspicuously dotted-glandular; seeds one per article, 3 × 2.2 mm, reniform, laterally flattened, black, glabrous, glossy.

Habitat and distribution: — Weberbauerella chilensis is found in the Atacama Desert in the Tarapacá region on a narrow altitudinal strip in the upper boundaries of absolute desert. This species grows on sandy soils between 2500 to 3600 meters altitude. It only appears above ground after precipitation, which is infrequent and irregular. Weberbauerella chilensis grows in open habitats that include other annual or geophyte ephemeral herbaceous species such as Metharme lanata Phil. (Zygophyllaceae) , Nolana tarapacana (Phil.) I.M.Johnst. (Nolanaceae) , and Tiquilia grandiflora (Phil.) A.T.Richardson (Boraginaceae) .

Etymology: —The specific epithet refers to Chile, where W. chilensis is found.

Phenology: —Flowering from September to March.

Conservation Status: — W. chilensis can be considered as Endangered (EN) under the IUCN (2012) categories and criteria B1ab(iii), since it is known only from a few locations and has a small area of occupancy, and because habitat loss is a latent threat, mainly from mining expansion.

Additional specimen examined (paratype): — CHILE. Tarapacá: Comuna de Pica, Quebrada Choja , 2440 m, 8 September 2012, L. Faúndez, F. Larraín & M. Escobar s.n. ( SGO 163429 !, CONC 177642 !) .

Additional specimens examined (related taxa): — W. brongniartioides : PERU. Mollendo: solo arenoso parce plantis compto ad marginem inferiorem formationis, quae "Loma"dicitur in altitude 100–200 m, 4 October 1902, A. Weberbauer 1513 (holotype B!, isotype F!). W. raimondiana : PERU. Arequipa: near Chala, province of Camaná, 300–400 m, 14 November 1949, R. Ferreyra 6498 (holotype US!, isotype US!).

Discussion: —The diagnostic characters of the genus Weberbauerella are mainly the presence of one or more deep tubers, stems, leaves and flowers densely covered with pustular glands, and imparipinnate leaves ( Ulbrich 1906) with more than 40 leaflets ( Lavin et al. 2001). The number of leaflets is not a morphological character mentioned in the protologue of the genus, however it is one of the diagnostic characters established here for W. chilensis , since this taxon has a lower number of leaflets (14–24) than the other species. Table 1 View TABLE 1 shows this and the other most important diagnostic morphological characters for the three species of Weberbauerella .

Figure 3 View FIGURE 3 shows that the known populations of W. chilensis are located ca. 600 km from its two congeneric species, which are only known from the area close to their type localities. In addition, there are large environmental differences between the species. Weberbauerella brongnartioides and W. raimondiana are endemics restricted to Lomas formations below 400 m at the arid desert coast ( León et al. 1996) in southern Perú ( Baldeon et al. 2006). These two species are located phytogeographically within the Arequipeño sector ( Galan de Mera et al. 1997) and have a marked dependence on ENSO events (El Niño-Southern Oscillation) for their proper development. In contrast, W. chilensis is a pre-Andean desert element in habitats under a strong influence of ‘La Niña’ events, which is an inverse climatic phenomenon.