Drosera roraimae Maguire & J. R. Laundon
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 roraimae

description: 24. Drosera roraimae (Klotzsch ex Diels 1906: 90) Maguire & J.R.Laundon in Maguire & Wurdack (1957: 333). Figures 8a, 20a, b
≡ D. montana var. roraimae Klotzsch ex Diels (1906: 90).
Type: — GUYANA. Cisäquatoriale Savannen-Provinz: Britisch-Guiana auf dem Roraima, November 1842, Schomburgk 1034 (holotype B-100272057!; isotype K, not found).
= Drosera montana var. robusta Diels (1914: 136).
Lectotype (designated here):— GUYANA. Auf dem Roraima, in der oberen Felsregion [on [Mount] Roraima, in the upper rock region [alpine level]], 2500 m, December 1909, Ule 8610 (B!; isolectotype K-000432543!).
Perennial, rosetted, caulescent, forming short to tall erect stems or columns covered by marcescent leaves, at least up to 10 cm tall (simple, but occasionally branched). Leaves semi-erect, with geniculate-involute vernation, distinctly petiolate, spatulate, petiole adaxial surface glabrous, abaxial surface densely eglandular-pilose; lamina obovate to suborbicular, stipule rectangular in outline, divided into several laciniate segments from the base. Scape curved at the base (rarely erect), glabrous at the base and becoming glandular-pilose towards apex, or entirely glabrous (only in Venezuelan material); some populations with flowers pendulous when in anthesis; sepals glandular-pilose or glabrous (only in Venezuelan material); petals white to light pink; gynoecium 3-carpelate, styles bifurcated at the base. Seeds ellipsoid to rectangular, with reticulate testa.
Illustrations: —Duno de Stefano (1995: 90, figs. 3g –n—habit and details); Silva & Giulietti (1997: 99, figs. 12N–T— habit and details); Duno de Stefano & Culham [1998: 703: fig. 561—habit (the roots incorrectly depicted) and leaf].
Distribution: — Guyana, Venezuela, and Brazil (North: AM, RR; Fig. 8a).
Habitat: —In Brazilian territory, D. roraimae is only found on the highlands of the tepuis and other northern Amazonic mountains, growing in sandy or peaty soils and in cracks of sandstone or quartzite. In Venezuela, D. roraimae also occurs in upland plains, growing in sandy to peaty soils in wet areas of the Gran Sabana. In Brazil, collected at 470–2730 m a.s.l.
Phenology:— Found in flower year-round.
Conservation status: —Least Concern (LC). Drosera roraimae is widespread in a relatively remote area in three South American countries (Brazil: AOO= 64 km 2, EOO= 156,100 km 2; global: AOO= 420 km 2, EOO= 351,460 km 2) where no severe threat is reported. In Brazil, it has been recorded from the Pico da Neblina (AM) and Monte Roraima (RR) National Parks as well as Serra do Aracá State Park (AM).
Notes: — Drosera roraimae superficially resembles D. communis, which also occurs on the uplands of the Guyana Shield, although the two are apparently never syntopic. Specimens of D. communis from the Guyana Shield can be easily distinguished from D. roraimae by more slender habit and usually the formation of shorter columns, with marcescent leaves conspicuously reflexed, the laxer rosettes with glabrescent leaves, and most reliably by the narrowly obovate lamina and fusiform seed shape.
Although all specimens examined from Brazil present glandular trichomes on the inflorescences, a few specimens of D. roraimae with completely glabrous scapes, pedicels and sepals were studied from Venezuela. These and other unusual specimens of the variable D. roraimae can nonetheless be safely distinguished from D. esmeraldae by the more robust habit, usually stem forming, the semi-erect leaves and the ellipsoid to rectangular seed with reticulate testa.
Drosera montana var. robusta was described based on the specimen Ule 8610, of which two duplicates are known, at B and K. Since Diels (1914) does not indicate the herbarium where the original material was studied, both specimens are considered syntypes, making it necessary to select a lectotype. Correa & Silva (2005) cite the specimen at K as the “ holotype ”, however, without including the words “here designated” it cannot be interpreted as inadvertent lectotypification since the year 2001 (ICN Art. 7.11, Turland et al. 2018), hence that name has not been properly lectotypified. Thus, we here select the specimen held at B as the lectotype, since it is the specimen personally annotated by Diels at the herbarium where he originally worked at the time he published that name.
Representative specimens examined: — BRAZIL. Amazonas: Barcelos, 03 km ao sul da parte central da Serra do Aracá, 1,5 horas leste do Rio Jaurari, 10 February 1984, do Amaral 1497 (INPA, NY); sandstone tepui 200 km N of Barcelos, Serra do Aracá, 27 December 1989, Nelson et al. 1706 (MO, NY). Rio Negro, Rio Cauaburí, 02 December 1965, Maguire et al. 60524 (NY). Santa Isabel do Rio Negro, Serra da Anta, cume, comunidade Yanomami Xamantá-Pohoro, 29 November 2003, Vicentini et al. 2100 (INPA, MO). São Gabriel da Cachoeira, Serra da Neblina, 30 December 1998, Rivadavia 768 (SPF). Roraima: Upper slopes of Serra Parima, S. of Auaris, 10 February 1969, Prance et al. 9811 (NY, P, US). Near summit of Serra Parima, south of Auaris airstrip, 30 July 1974, Prance et al. 21563 (INPA, MO, NY). Setor brasileiro no alto do Monte Roraima, 01 January 2003, Rivadavia 1491 (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 54-56, DOI: 10.11646/phytotaxa.553.1.1, http://zenodo.org/record/6796689