Salicornia cuscoensis Gutte & G.K. Müll. ex Freitag, M.A. Alonso & M.B. Crespo, 2017

Salicornia cuscoensis Gutte & G.K. Müll. ex Freitag, M.A. Alonso & M.B. Crespo View in CoL , sp. nov. ( Fig. 1 View FIGURE 1 & 2D − F View FIGURE 2 )

Type:— PERU. Cusco, Provincia Quispicanchi: Distrito de Lucre, a 300 m del cruce de la carretera Huacarpay-Lucre , 13°36’43.03”S 71°44’9.92”W, 3200 m, 30 December 2016, Mendoza & Cano 6648 (holotype USM-297396 ! GoogleMaps , isotypes ABH! GoogleMaps , CUZ! GoogleMaps , KAS! GoogleMaps , MA! GoogleMaps ).

‒ “ Salicornia cuscoensis Gutte & G.K. Müll. ” in Müller & Gutte (1985: 403), nom. nud. (Art. 38 Ex. 1 of the ICN; McNeill et al., 2012).

‒ ” Sarcocornia cuzcoensis Freitag, M. A. Alonso & M.B. Crespo” in Kadereit et al. (2007: 1167) (footnote), nom. nud.

Diagnosis:— Species insignis a S. andina and S. magellanica accedens, sed eis valde diversa et facile distinguitur foliis subacutis, inflorescentiis longioribus (8–40 mm) et seminibus minoribus ad 0.9 × 0.7 mm. A priore tamen differt caulibus repentibus (non subcaespitosis); ramis gracilioribus parce suffruticosis; seminibus pilis erectis vestitis (in illa pilis omnibus adpressis). A S. magellanica tamen discrepat caespites minores efformantibus, caulibus brevioribus 2–6 cm alt. (non usque ad 15 cm alt.); seminibus omnibus pilis simplicissimis vestitis (in illa nonnunquam bifidis).

Description:—Perennial, suffruticose, prostrate, creeping with delicate branches, rooting at the basal nodes, and forming dense, carpet-like clumps of circular shape. Stems 2–3(–6) cm high, 1–2 mm diameter, giving the plant the appearance of an annual. Leaves opposite, succulent, fused along the internodes giving an articulated aspect to the stems; branch segments 24–53(–60) × 1–2 mm, apex subacute with a distinct hyaline margin, ca. 0.2 mm. Inflorescences in dense terminal spikes; flowers in groups of 3, each one inserted in an individual cavity isolated by longitudinal septa. Spikes (8–)16–30(–40) × (2–)2.5–3(–4) mm. Anthers 0.2 mm. Seeds 0.8–0.9 × 0.6–0.7 mm, brown, with straight short and simple hairs (length/width: 0.03–0.1 mm), accompanied with some papillae.

Etymology:—The epiteth cuscoensis refers to the region to which the species is native and from where it was first found.

Habitat:—Wet saline soils with salt efflorescences during the dry season.

Distribution:— Salicornia cuscoensis is known from high Andean saltmarshes around 3200 m a.s.l., near Cusco and Ayacucho, Peru.

Taxonomic and phylogenetic relationships:— Salicornia cuscoensis shares a similar distribution area with two congeners, i.e. S. andina and S. pulvinata (see Ela 1980, Giusti 1997, Roque & Ramírez 2008). However, these three species were never found growing together.

Salicornia pulvinata occurs in Argentina, Chile, Bolivia and Peru at 3500–4000 m, being the Salicornia species reaching the highest elevation. It forms small and compact cushions up to 5 cm tall, with carinate leaves, minute inflorescences (up to 2 mm long), and the seed testa loosely covered with minute hairs up to 0.04 mm long, and partially also bearing very short, thickwalled, papillalike, simple straight hairs. The distinct general habit and seed features easily allow distinguishing of S. pulvinata from S. cuscoensis and the rest of S-American relatives (see identification key below and Tab. 1 View TABLE 1 ).

Salicornia andina appears to be restricted to the high Andean saltmarshes in Argentina, Bolivia and Chile, between 2300 and 3880 m a.s.l. According to Alonso & Crespo (2008) morphological affinities are found to S. cuscoensis , though remarkable differences exist allowing separation (see Table 1 View TABLE 1 ). S. andina forms subcaespitose dwarf, cushionlike clumps. It is many-branched, with stems up to 10 cm high, rather robust [not with an annual-like habit by delicate stems 2–3(–6) cm high as in S. cuscoensis ]. In S. andina leaves are obtuse, and seeds are larger (1.4 × 1.1 mm) with scarce appressed straight hairs which are more abundant, erect and often longer (up to 120 μ m) than in S. cuscoensis ( Fig. 2 View FIGURE 2 ). With the description of S. cuscoensis , reports to S. andina in Peru are to be disregarded, and therefore the latter is to be excluded from the Peruvian flora.

In their molecular study of the Salicornia-Sarcocornia complex Kadereit et al. (2007: fig. 4A) presented a phylogeny in which “ Sarcocornia cuzcoensis Freitag, M. A. Alonso & M.B. Crespo” was included. Their ETS tree showed a strongly supported monophyletic clade (100% BS) including sampled American taxa of Salicornia subg. Amerocornia . The basal lineage of the whole clade was S. utahensis (Tidestrøm 1913: 13) Scott (1977: 369) with a strong support (100% BS). The rest of American taxa nested together in an also strongly supported subclade having the Atlantic species S. ambigua at the base, and a sister clade that led to an unresolved group in which the new species falls close to S. neei and S. pacifica . However, the branch leading to S. cuscoensis is longer, which indicates more substantial differences. According to the data of Guilló (2013), phylogenetic trees of ITS and ETS (each alone or combined) yielded similar results, even including the peculiar S. pulvinata which was placed at the base of the tree, close to S. utahensis , and both species representing the oldest lineages in the American clade.

Morphological relationships of Salicornia cuscoensis to S. pacifica and S. neei are very weak. Both latter species are similar to each other and probably not specifically different. They are woody shrubs up to 1 m high, with longer and wider inflorescences (10–40 × 3–4 mm), the terminal spike usually accompanied with many shorter lateral ones, and seeds coated all over with longer and hooked or curved hairs. Furthermore, S. neei and S. pacifica occur in coastal saltmarshes of the Pacific ocean. The third Salicornia species from coastal S-America, S. magellanica from saltmarshes near the Magallanes Strait in southern Patagonia and Tierra del Fuego, seems to be closer to the new species at the first glance, but it forms very large clumps, with erect branches up to 15 cm in height, usually shorter and wider inflorescences (0.8–15 × 3–5 mm), and larger seeds (1.3 × 0.9 mm), with the testa sparsely covered all over with spreading hairs which are straight or slightly curved at the apex, many of them bifid.