Drosera tomentosa Saint-Hilaire 1826
Creators: name: Gonella, Paulo Minatel
name: Sano, Paulo Takeo
name: Rivadavia, Fernando
name: Fleischmann, Andreas
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Caryophyllales
Droseraceae
Drosera
Drosera tomentosa

description: 30. Drosera tomentosa Saint-Hilaire (1826: 261). Figures 7e, 22a–d
Lectotype (designated by Rivadavia et al. 2014: 163):— BRAZIL. Minas Gerais: Marais près Itambé, Cap. des Mines [marsh near Itambé (current municipality of Itambé do Mato Dentro), Minas Gerais], s.d., Saint-Hilaire M 378 [lectotype P-749166!, fifth specimen from left; isolectotypes P-00749166! (individual plants indicated on sheet), P-00749167!, P-04962569!, K-000432538! (the two plants on the top right), MPU-012262 image!].
≡ D. montana var. tomentosa (Saint-Hilaire 1826: 261) Diels (1906: 89).
= Drosera tomentosa var. glabrata Saint-Hilaire (1826: 262).
Lectotype (designated here):— BRAZIL. MINAS GERAIS: cueilli près Milho verde par Laruotte [collected near Milho Verde (current municipality of Serro) by Laruotte], s.d., Saint-Hilaire M-476 (P-749168!; isolectotypes MPU image!, P-749169!).
Perennial, rosetted, acaulescent or forming short, prostrated columns up to 2 cm tall. Leaves decumbent, with circinate vernation, obovate to oblong-obovate (rarely oblong), with wide petioles (0.4–3.0 mm in width), apical tentacles usually inconspicuously distinct and in number of 5–9, up to 5 mm long, stalk up to 0.3 mm wide at base, with rectangular-linear head up to 0.6 mm long; stipules rectangular in outline, apical 1/2 to 1/3 fimbriate or divided into three unequal fimbriate segments. Scape erect at the base, glandular trichomes absent in the basal third of scape; sepals narrowly ovate to oblong-ovate, 1.5–3.0 × 0.6–1.3 mm; petals pink; gynoecium 3-carpelate, styles bifurcated at the base. Seeds ovoid to ellipsoid, testa reticulate (based on Rivadavia et al. 2014).
Illustrations: — Ferrero & Mello-Silva (2011: 15, figs. 1D–F—habit and details— D. tomentosa var. glabrata); Rivadavia et al. (2014: 169, 170, figs. 11, 12—habit and details, both varieties).
Distribution: — Brazil (Northeast: BA, SE; Central-West: GO; Southeast: MG), endemic. The core distribution of D. tomentosa occurs along the Espinhaço Range in Minas Gerais and Bahia, but also extending further south to the northern tip of the Serra da Mantiqueira (Serra do Ibitipoca), southwest to the Serra da Canastra (MG), west to the Chapada dos Veadeiros (GO), east to the Pico da Aliança and Serra do Padre Ângelo (MG), and finally northeast to coastal Bahia and the Serra de Itabaiana highlands (SE; Fig. 7e).
Habitat: — Drosera tomentosa is found in a wide range of habitats in wet areas of campos rupestres vegetation where it occurs at elevations between 700–2050 m, in sandy to peaty soils and also in cracks of sandstone. It also extends to sea level in restinga vegetation of coastal Bahia, where it grows in sandy soils. Drosera tomentosa is one of the few Brazilian species that can also be found growing semi-shaded inside riparian forests along river margins, adjacent to campos rupestres vegetation.
Phenology: —Mostly collected in flower between June and September, with occasional individuals flowering year-round.
Conservation status: —Least Concern (LC). Drosera tomentosa is widespread and probably the most common sundew species of the campos rupestres of eastern Brazil (AOO= 188 km 2, EOO= 700,677 km 2), where it occurs in several National Parks (Chapada Diamantina, Chapada dos Veadeiros, Sempre-Vivas, Serra da Canastra, Serra do Cipó) and State Parks (MG: Biribiri, Botumirim, Grão Mogol, Ibitipoca, Pico do Itambé, Rio Preto, Serra do Cabral, Serra do Intendente, Serra Nova; BA: Sete Passagens).
Notes: — Drosera tomentosa is most similar to D. montana, but is distinguished by the flowering period (June to September vs. December to March), lack of a dormancy period (vs. dormancy from May to November), obovate to oblong-obovate leaves (vs. oblong to spatulate), lack of glandular trichomes on the basal 1/3 of scape, then present and increasing in size and density towards the apex (vs. glandular trichomes uniform in size and density from base to apex of the scape), and scapes densely eglandular-pilose (but not always, see below).
Drosera tomentosa and D. tomentosa var. glabrata were re-established from synonymy of D.montana by Rivadavia et al. (2014), following Saint-Hilaire’s (1826) original taxonomic circumscriptions. However, recent taxonomic works dealing with delimitation of Drosera species have generally opted to discontinue the application of infraspecific ranks, either by raising varieties and subspecies to species rank or by placing these under synonymy (Lowrie 2014, Gonella et al. 2014), often describing the variation as geographical morphotypes (this work, Gonella et al. 2014, Rivadavia et al. 2014). The adoption of morphotypes instead of varieties is a way to better reflect the subtle morphological variation observed within a species when there is no data to support the monophyly of this variation in an infraspecific category. Such is the case with D. tomentosa, which presents a continuum of variation regarding the presence and distribution of eglandular trichomes on the scape, from absent to densely tomentose (Rivadavia et al. 2014). Therefore, in order to be consistent with previous works that have adopted morphotypes to describe the variation within D. latifolia (Gonella et al. 2014) and D. montana (Rivadavia et al. 2014), as well as D. hirtella and D. schwackei in the current work, we here accept D. tomentosa with no varieties and with two morphotypes instead.
i. “ Type morphotype”: previously D. tomentosa var. tomentosa (Rivadavia et al. 2014), this morphotype is characterized by scapes densely eglandular-pilose on the basal half, decreasing in density towards the apex. This morphotype is the most common in the northern and eastern ranges of the species, especially on the Chapada Diamantina. Found in Bahia, Minas Gerais, and Sergipe.
ii. “glabrate morphotype”: previously D. tomentosa var. glabrata (Rivadavia et al. 2014), this morphotype is characterized by scapes exclusively glandular-pilose from base to apex (eglandular trichomes absent) to sparsely eglandular-pilose on the basal third of the scape. It is the most common morphotype in the southern and western distribution of the species. Found in Bahia, Minas Gerais, and Goiás.
Both morphotypes are sympatric and often syntopic on the Espinhaço Range in Minas Gerais, where individuals with intermediate features can be occasionally found (for a distribution map of the varieties, see Rivadavia et al. 2014: 164).
Drosera tomentosa is known to form natural hybrids with D. grantsaui (namely D. × fontinalis, see below under this nothotaxon), and occasionally also with D. latifolia and D. villosa (Gonella et al. 2014).
Specimens examined: —For an extensive listing, see Rivadavia et al. (2014: 166–168).
Additional specimens examined: — BRAZIL. Bahia: Pindobaçu, Serra da Fumaça, Poço das Estrelas, 11 October 2019, Souza & Leodegário 77 (HURB). Minas Gerais: in altis pratis arenosis ad Serra de Grão Mogol, s.d., Martius s.n. (M). Alvarenga, Pico da Aliança, 09 July 2014, Gonella et al. 689 (SPF). Conselheiro Pena, Serra do Padre Ângelo, córrego da Regina, aos pés da Serra do Pinhão, 03 December 2018, Gonella et al. 960 (SPF).
description: Published as part of Gonella, Paulo Minatel, Sano, Paulo Takeo, Rivadavia, Fernando & Fleischmann, Andreas, 2022, A synopsis of the genus Drosera (Droseraceae) in Brazil, pp. 1-76 in Phytotaxa 553 (1) on pages 61-64, DOI: 10.11646/phytotaxa.553.1.1, http://zenodo.org/record/6796689