Pinguicula dertosensis — Vorstman's Guide to the Carnivorous Plants

Identification

A rosette of yellow-green, oblong leaves, greasy to the touch and with margins curled upward; on steep walls they are held obliquely rather than flat. In flower the plant reaches five to twenty centimetres, generous for a European butterwort. The scapes are glabrous and each carries one two-lipped flower, violet to blue-violet, with a paler throat and three broad lobes to the lower lip. The spur is long and straight, projecting obliquely backwards; that long spur places the species in the large-flowered western Mediterranean group. Flowering runs from April to July.

Similar species

The nearest relatives are the other Iberian rock butterworts, and the history is confusing: the taxon was long carried as a subspecies of Pinguicula grandiflora and only later recognised as a species of its own. On top of that, the populations in the Sierra Tejeda, formerly also called P. dertosensis, were separated in 2020 as Pinguicula tejedensis. The practical consequence for the field-guide reader: P. dertosensis in the strict sense grows only in the north-east, in the Ports and around them. Anything reported under that name in Andalusia now belongs elsewhere.

The trap and how it works

A flypaper trap dependent on damp and shade. The leaf bears stalked glands with an adhesive droplet and sessile glands that release enzymes only once prey is lying on them. In a cool limestone gorge the catch consists of mosquitoes, gnats, small beetles and springtails that seek out the humid air along the water. After a catch the leaf margin rolls over the prey so the digestive fluid stands in a shallow dish; on a near-vertical wall that is essential. The limestone itself supplies hardly any nitrogen, and the plant draws nearly everything it needs from what it catches.

Habitat and ecology

Damp limestone rock in cool, shaded gorges: dripping faces, overhanging rock bands where water emerges from a crack, and the wet zone beside a mountain stream. The plant roots in crevices and in moss cushions on the rock and tolerates no drought. Sites generally face north or north-east, where the sun barely reaches and humidity stays high even in summer. In a landscape that is otherwise Mediterranean-dry, these gorges form cool islands in which ferns and mosses of far more northern regions persist alongside the butterwort.

Distribution and elevation

The massif of the Ports de Tortosa-Beseit and adjoining mountains in the Tinença de Benifassà, on the border of Catalonia, Aragon and the province of Castelló. The range is small and sharply bounded, with a strongly Ibero-Levantine character. Our own species list gives only 'Spain (Catalonia)'; that is not wrong but is incomplete, since a substantial share of the sites lie on the Valencian and Aragonese sides of the same massif. The former Andalusian records have belonged to a different species since 2020.

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 7 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 wild varieties are recognised. What varies is plant size, from five to twenty centimetres depending on the wetness and shelter of the site, and the saturation of the violet. The nomenclatural history is more eventful than the plant: from subspecies of P. grandiflora to a species in its own right, and then a narrowing of the range with the segregation of the Andalusian populations. Anyone consulting older literature must therefore check which circumscription is being used.

Where and when to see it

May is usually the best month: the walls are still dripping with spring water and flowering is under way. Search the cool north-facing gorges of the massif, along the streams and under overhanging rock bands. Look at eye level and above — the rosettes often sit above the path in a wet crevice — and use binoculars rather than climbing. The rock is loose and the moss cushions the plant roots in peel away at a touch; looking from a distance yields more and costs the population nothing.

Conservation status

The species counts as of least concern. That owes much to the gorges of the Ports being hard to reach, lying inside protected land and being impossible to reclaim. Even so the range is small and every individual site depends on a steady supply of water through the limestone. The real risks are the tapping of springs, falling water tables in longer droughts, and recreational pressure in the most popular gorges, where climbing and canyoning touch precisely the wet walls the plant occupies. Collection of wild plants is a further concern for this recognisable, photogenic species. CITES does not apply.

Scientific name

Pinguicula dertosensis | (Cañigueral) Mateo & Crespo, 1995

Originally described in 1957 as a variety of Pinguicula grandiflora by Francesc Cañigueral, in Collectanea Botanica (Barcelona) 5: 413; raised to the distinct species rank by Gonzalo Mateo and Manuel B. Crespo in 1995. The type area lies at the Puertos de Tortosa, in Tarragona province, Spain. The species name dertosensis derives from "Dertosa", the classical Latin name for Tortosa, the city near the type locality.

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