Drosera hirticalyx R. Duno & Culham 1995
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 hirticalyx

description: 16. Drosera hirticalyx Duno & Culham (1995: 241). Figures 8b, 17a–c
Type: — VENEZUELA. Amazonas: Dpto. Atabapo, Cerro Marahuaca-Huha, cumbre altiplanicie no arbolada, más o menos plana, con piedras expuestas, río abajo, 2580 m, 31 January 1982, Steyermark et al. 125982 (holotype NY-03838894!; isotype VEN).
Perennial, rosetted, acaulescent or often forming erect columns densely covered by marcescent leaves. Leaves decumbent, with geniculate vernation, spatulate, petiole short and discreet, gradually broadening into the obovate lamina, leaves drying black; stipules rectangular in outline, divided into multiple laciniate segments from the base. Scape erect at the base, glandular-pilose towards the apex; sepals glandular-pilose mostly towards the base; petals white; gynoecium 3-carpelate, styles bifurcated at the base. Seeds ovoid, dark brown to back, testa reticulate.
Illustrations: — Duno de Stefano & Culham (1995: 242, figs. 1A–E—habit and details); Duno de Stefan & Culham (1998: 702, fig. 559—habit, leaf and calyces).
Distribution: — Venezuela, Guyana, and Brazil (North: AM, RR). In Brazil the species is only known from the summits of Mt. Neblina (AM) and Mt. Roraima (RR), in both cases on the border with Venezuela (Fig. 8b).
Habitat: —Perennially moist to wet sandy or peaty soils, growing in islands of vegetation over rock outcrops, along the drainage lines of large rocks, or in cracks of sandstone in wet places and in peaty soil along streams and in bogs, at elevations between 1900–2730 m.
Phenology:— Found in flower year-round.
Conservation status: — Least Concern (LC). Drosera hirticalyx is found in remote and largely protected areas and is not likely to face population size reduction in the near future from direct anthropogenic impact, but may be susceptible to habitat reduction due to climate change (global: AOO= 48 km 2, EOO= 84,048 km 2). In Brazil it occurs inside the Monte Roraima and Pico da Neblina National Parks.
Notes: — Drosera hirticalyx is superficially reminiscent (especially in dried specimens) of species in the D. montana alliance [also including D. tentaculata, D. tomentosa and D. spirocalyx], due to its leaves with petiole gradually broadening into an obovate lamina. However, D. hirticalyx is very easily distinguished from the D. montana complex by its stipules which are divided from the base into laciniate segments (vs. stipules entire up to half length, then fimbriate), absence of unifacial marginal glands on the apical leaf margin (vs. present in all four species of the D. montana alliance to some degree), white petals (Fig. 17c; vs. pink), geniculate leaf vernation (vs. circinate in all but D. tentaculata, which also presents geniculate vernation) and the fact that plants turn black when dried (vs. brown). It is further distinguished by robust glandular trichomes on the calyx (Fig. 17b), in contrast to few smaller trichomes on pedicels and scape (these parts appear sub-glabrous), while in the D. montana alliance, glandular trichomes of the scape, pedicels and sepals present a constant, similar size. Moreover, both are only distantly related phylogenetically and also differ in terms of chromosome number, with D. hirticalyx being a member of the diploid D. sect. Drosera, and the D. montana affinity belonging to the tetraploid D. sect. Brasilianae.
Plants from Pico da Neblina (AM) are relatively small in comparison to the very robust plants that occur on Cerro Marahuaca and Cerro Duida (Amazonas, Venezuela), whereas plants growing on Mount Roraima and Kukenán tepui (the former comprising a small part of Brazilian territory, RR) are intermediate in size. Despite this significant variation in size, the defining characters of this species are constant and there appear to be no morphological characters distinguishing the different geographical populations of D. hirticalyx.
Specimens examined: — BRAZIL. Amazonas: São Gabriel da Cachoeira, Serra da Neblina, trilha para o Pico da Neblina, 31 December 1998, Rivadavia 770 (SPF). Ridge line on Venezuela-Brazil border, Cerro Neblina, 17 April 1984, Gentry & Stein 46710 (MO). Roraima: Setor brasileiro do Monte Roraima, 01 January 2003, Rivadavia-Lopes et al. 1488 (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 45-46, DOI: 10.11646/phytotaxa.553.1.1, http://zenodo.org/record/6796689