Drosera quartzicola — Vorstman's Guide to the Carnivorous Plants

Identification

A perennial rosette, stemless or with short columns up to 40 mm tall. The leaves are semi-erect and lanceolate, with the petiole about as long and as wide as the blade. At the base are triangular, golden-brown stipules 6 to 8 mm long. The scape is 17 to 115 mm long and carries pink flowers; the pistil has three carpels with forked styles. The seeds are narrowly oblong-ovate, 0.7 to 0.8 mm, with a black, reticulate testa.

Similar species

The closest relative is Drosera chrysolepis, which also has golden-brown stipules. D. chrysolepis, however, forms distinct stems, has a petiole narrower than the blade and longer scapes. Other sundews in the same area almost always grow in wetter places; the combination of dry quartz-gravel ground and golden-brown stipules is characteristic of D. quartzicola.

The trap and how it works

An active flypaper trap. The semi-erect leaves catch small insects walking over the gravel or flying low above it. In this dry, open habitat ants and small flies are probably the main prey.

Habitat and ecology

Strikingly dry for a sundew: relatively dry parts of the campos rupestres, on fine silica sand mixed with white quartz gravel, at 1,100 to 1,360 m (D2, R3). Where most Brazilian sundews seek seepages and wet hollows, this species stands on open, quickly drying ground that stays moist only in the rainy season.

Distribution and elevation

Endemic to a small part of the southern Espinhaço range in Minas Gerais, south-eastern Brazil, divided over six small populations. Precise localities are not given in this guide because the species is considered critically endangered.

Recorded (one-degree cells)

Distribution based solely on records at GBIF (Global Biodiversity Information Facility), not on TDWG regions — those are often far larger than the actual range. The light halo is the area around a record, the dark core the record itself. The darker square is the only one-degree cell — roughly a hundred and ten kilometres — in which the species has been recorded, from all GBIF records. This is coarser than for most species because hardly any record of this plant carries an accurate coordinate. It shows where the species has been seen, not where it occurs: an empty square means nothing.

Forms and variation

No varieties are recognised. The species is one of the clearest examples of the extreme local endemism of the campos rupestres: a distinct, drought-tolerant lineage within a group of mostly marsh plants, confined to a single mountain massif.

Where and when to see it

Not a species to search for actively; the populations are small and the gravel ground is vulnerable to trampling. Anyone hiking in the mountains of Minas Gerais who sees pink-flowering sundews on dry white gravel in the rainy season, November to April, should leave them be and report the sighting to researchers.

Conservation status

Not assessed for the global IUCN Red List and not listed in CITES. The authors assessed the species as critically endangered: about 340 known plants in six populations. The main threats are human-caused fires, invasive grasses closing over the open gravel patches, and climate change altering the habitat. That is the authors' assessment, not an official IUCN category.

Scientific name

Drosera quartzicola | Rivadavia & Gonella, 2011

Drosera quartzicola was described in 2011 by Fernando Rivadavia and Paulo Minatel Gonella, in the journal Phytotaxa, volume 29, page 34. The species had already been rediscovered by Rivadavia and Gonella in 1996 (and collected without recognition even earlier, in the early 1990s), but was only formally published in 2011. The type specimen was collected on 19 April 2010 by Paulo M. Gonella, in the Travessão area near Santana do Riacho, municipality of Conceição do Mato Dentro, Minas Gerais state, Brazil, at an elevation of about 1,360 m, in the campo rupestre quartz-gravel landscape. The epithet quartzicola is composed of "quartz" and the Latin suffix -cola ("dweller of"), and thus means "quartz-dweller". It refers directly to this species' characteristic habitat: silica/quartz sand surrounded by white quartz gravel in the Brazilian campo rupestre.

World Checklist of Vascular Plants (WCVP), via Plants of the World Online (POWO), Royal Botanic Gardens, Kew.