Platystele peruviana Rizo-Patron, 2022

Rizo Patrón, Federico L., 2022, Platystele peruviana sp nov. (Orchidaceae), the smallest orchid from Peru, Phytotaxa 564 (1), pp. 113-120 : 114-118

publication ID	https://doi.org/ 10.11646/phytotaxa.564.1.9
DOI	https://doi.org/10.5281/zenodo.7082563
persistent identifier	https://treatment.plazi.org/id/03A2879A-C122-FF88-8597-3D55FEB328BD
treatment provided by	Plazi
scientific name	Platystele peruviana Rizo-Patron
status	sp. nov.

Treatment

Platystele peruviana Rizo-Patron , sp. nov. ( Figures 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 )

Type: — PERU. Oxapampa : Gramazú, 1934 m, 01 September 2020, FRV 52 (holotype HOXA!) .

Platystele peruviana is similar to P. psix Luer & Hirtz , but differs from the lateral parallel falcate sepals (vs. oblique not falcate), ovate elliptic lip (vs. ovate lanceolate), and a large circular glenion (vs. medium semi square glenion).

Description:— Plant epiphyte, caespitose, erect up to 14 mm tall: Roots basal, slender, up to 1 mm diameter, with compressions every 2 to 3 mm; Ramicauls slender, suberect, 1 mm long, covered by 2 thin tubular sheaths; Leaves thickly coriaceous, conduplicate, elliptic, erect, apex subacute, tridenticulate, 8–9 × 3.5–4 mm, abscission layer visible, short conduplicate petiole, 2 mm long; Inflorescence an erect raceme, with successive flowers, up to 12 mm long, peduncle 9 mm long; Flowers flat, sepals and petals pale yellow to transparent towards the margins and darker towards the midvein, covered with glandular hairs, Dorsal sepal lanceolate, apex acute, 3.0 × 0.75 mm; Lateral sepals more or less parallel, subfalcate, 3 mm × 1 mm, connated a quarter of the length of the sepals; Petals, lanceolate, with the upper margin curved towards the top in the central third, the lower margin strait, 2 × 0.5 mm; Lip red with an orange tip, with whitish-yellow glandular hairs, ovate - elliptic, with the apex acute, 1.0 × 0.75 mm, with a circular glenion in the base; Column pale yellow, short, 0.3 mm tall; 0.4 mm long, 0.75 mm wide; Anther with more intense yellow in comparison to the column, 0.25 × 0.25 mm; Pollinia yellow, ovoid from the side.

Distribution and ecology:— Platystele peruviana is found only in Oxapampa, Pasco, Peru ( Figure 1 View FIGURE 1 ) and could be considered, at this moment, the smallest orchid in Peru. Oxapampa is part of the Oxapampa Ashaninka Yanesha Biosphere Reserve – BIOAY.

Etymology: —The specific epithet has been chosen to honor Peru, the country where the type specimen of this species was found.

Taxonomic Discussion: — Platystele peruviana is similar to Platystele psix Luer & Hirtz with the exception of the lateral sepals, which are more parallel than oblique and with a subfalcate shape ( Figures 2A View FIGURE 2 and 3A View FIGURE 3 ). Also, the lip in P. psix is ovate-lanceolate with an acute apex, while the lip of P. peruviana is ovate-obtuse, resembling that of P. napintzae Luer & Hirtz ( Luer 1992: 114) ( Figures 2E View FIGURE 2 and 3C View FIGURE 3 ). The glenion is circular and approximately half as wide as the lip base, which is semi square in P. psix ( Figures. 2E View FIGURE 2 , 3C 3D View FIGURE 3 , 4A, 4C View FIGURE 4 and Table 1 View TABLE 1 ). A comparison between P. peruviana , P. psix , P. lancilabris (Schlechter 1923: 102) , P. oxyglossa ( Garay 1974: 120) and P. pisifera (Luer 1977: 232) , which can be found in nearby locations, is presented in Table 1 View TABLE 1 . The descriptions of the different Platystele species mention that roots are coarse, slender and fleshy ( Luer 1990, 1991, 1992, Jost & Iturralde 2017). No description mentions if any species have little constant compressions along the roots as are shown in Figure 2F, 2G View FIGURE 2 and 4D View FIGURE 4 . Connation of lateral sepals is also different from other species. This is shown in Figure. 4B View FIGURE 4 and Table 1 View TABLE 1 .

In the treatment for Platystele ( Luer 1990) and its addenda ( Luer 1991, 1992), nine Peruvian species are bigger than 5 cm from the base. Only Platystele psix has a plant bigger than 2 cm from the base, and P. peruviana is only 1.4 cm. from the base.