Drosera spirocalyx — Vorstman's Guide to the Carnivorous Plants

Identification

A small perennial rosette plant with spatulate leaves densely set with tentacles, turning red in sun, and a scape with a few flowers. The distinguishing character lies, as the name says, in the calyx. Exact measurements, a confirmed flower colour and a precise account of the calyx character could not be checked from the original sources; the size fields are therefore left empty.

Similar species

The closest relatives are Drosera montana, Drosera tomentosa and Drosera schwackei, species that all used to fall under D. montana. D. tomentosa is densely woolly; D. montana in the strict sense grows in the higher mountains of south-eastern Brazil. In the 2022 synopsis D. spirocalyx is shown on one distribution map with D. schwackei and Drosera chimaera, two other species confined to Minas Gerais. Identification needs a flowering plant, a hand lens and the key in the revision.

The trap and how it works

An active flypaper trap. The tentacles catch small insects walking over the ground or flying low above it, after which the surrounding tentacles bend towards the prey. The rosette lies close to the ground, so mainly crawling prey is caught.

Habitat and ecology

Open, wet to damp places in the campos rupestres of Minas Gerais: seepage zones along rock slabs, wet sandy ground and stream edges in quartzite country (R1, W4, D2). The plant needs full sun and soil that stays moist during the growing season.

Distribution and elevation

Endemic to the state of Minas Gerais in south-eastern Brazil, according to the distribution maps in the 2022 Brazilian synopsis. The exact location within the state and an altitudinal range could not be checked here.

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 cells are 2 one-degree squares — 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: the locality of poached species is obscured at source. At this scale that obscuring disappears into the noise. The cells show where it has been seen, not where it occurs: an empty square means nothing.

Forms and variation

No varieties are recognised. The species belongs to the D. montana complex, revised in 2014, when former varieties were raised to species and new species described. Older records of D. montana from Minas Gerais may therefore also refer to this species.

Where and when to see it

In the wet season, November to March, search seepages in the quartzite mountains of Minas Gerais. Photograph flowers from the side and from below so that the calyx is clearly visible; without that detail the species can scarcely be separated from its relatives.

Conservation status

Not assessed for the global IUCN Red List and not listed in CITES. The species is confined to a single state; little has been published on population size or trends. Threats to the campos rupestres are fire, invasive grasses, mining and tourism.

Scientific name

Drosera spirocalyx | Rivadavia & Gonella, 2014

Drosera spirocalyx was described in 2014 by Fernando Rivadavia and Paulo Minatel Gonella, published in Phytotaxa, volume 172: 155. The holotype (SPF 213602) was collected by Fernando Rivadavia on 12 September 1999, along a trail in the Serra do Cipó, municipality of Santana do Riacho, in the state of Minas Gerais, Brazil. The name is compounded from Greek "speira" (spiral, coiled) and Latin "calyx" (calyx/sepals), likely referring to the twisted or spiral-shaped sepals of the species; however, this etymological interpretation could not be fully confirmed.

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