Drosera spirocalyx Rivadavia & Gonella

Gonella, Paulo Minatel, Sano, Paulo Takeo, Rivadavia, Fernando & Fleischmann, Andreas, 2022, A synopsis of the genus Drosera (Droseraceae) in Brazil, Phytotaxa 553 (1), pp. 1-76 : 60-61

28. Drosera spirocalyx Rivadavia & Gonella in Rivadavia et al. (2014: 155). Figures 6c, 21d–f

Type: — BRAZIL. Minas Gerais: Santana do Riacho , trilha para velózias gigantes, 12 September 1999, Rivadavia 1165 (holotype SPF-213602!; isotypes BHCB!, P!) .

Perennial, rosetted, acaulescent or often forming very short compact columns of dead marcescent leaves. Leaves decumbent, with circinate vernation, oblanceolate to narrowly obovate, densely eglandular-pilose on the adaxial petiole surface and whole abaxial leaf surface, apical tentacles inconspicuously distinct, up to 4 mm long; stipules rectangular in outline, apical 1/3 to 2/3 divided into three unequal fimbriate segments. Scapes erect at the base, minutely glandular-pilose, trichomes becoming denser towards the apex; sepals suborbicular to broadly ovate with rounded (rarely subobtuse) apex, overlapping (torsive or spirally contorted aestivation) when in bud and the lateral margins of adjacent sepals forming a pyramidal projection at their adnate bases, glandular pilose; petals pink; gynoecium 3- carpelate, styles bifurcated at the base. Seeds ellipsoid to oblong, testa reticulate (based on Rivadavia et al. 2014).

Illustrations: — Rivadavia et al. (2014: 157, fig. 6—habit and details).

Distribution: — Brazil (Southeast: MG), endemic to the Serra do Cipó, central Minas Gerais (Fig. 6c).

Habitat: — Drosera spirocalyx grows in relatively dry areas of campo rupestre vegetation in sandy soils, often with white quartz gravel. Found between 1000–1350 m a.s.l.

Phenology: —Flowering individuals are observed in the dry season, between July to November.

Conservation status: —Endangered (EN) B1ab(iii)+2ab(iii). Only a handful of populations are known, although these vary widely in number, from a few to hundreds of individuals each. Based on the restricted distribution and fragile habitats occupied by D. spirocalyx , threatened by mining and invasive grasses, Rivadavia et al. (2014) designated it VU. However, both AOO (24 km 2) and EOO (110 km 2) suggest a more concerning scenario of threat, and the species is here considered EN, a status further supported by future threats to habitat quality as a result of climate change. Drosera spirocalyx occurs inside the Serra do Cipó National Park and in the Parque Natural Municipal do Ribeirão do Campo.

Notes: —Specimens of D. spirocalyx have been historically identified as D. montana based on the similar leaf morphology. Although D. spirocalyx does indeed belong to the D. montana species alliance ( Rivadavia et al. 2014), it is easily distinguished from these allied species by the villous adaxial petiole surface and abaxial leaf surface (Fig. 21d), relatively short scapes with few flowers (up to 4), and suborbicular to broadly ovate sepals with rounded apex (Fig. 21e).

Specimens examined: —For an extensive listing, see Rivadavia et al. (2014: 158–159).

Additional specimen examined: — BRAZIL. Minas Gerais: Santana do Pirapama, Serra do Cipó, Capela de São José , 25 November 2009, Zappi 2605 (K) .