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Pinguicula lavalvae
In the uplands east of Naples, where the Monti Picentini hold the sources of the Sabato and the Calore, a new butterwort was described in 2014. Pinguicula lavalvae is the most contested species in this group: it was separated from its relatives by geometric shape analysis, and not everyone is convinced.
No photograph of this species under a Creative Commons licence or in the public domain is in the guide yet.
Identification
A rosette of yellow-green, broadly elliptic to obovate leaves, greasy to the touch, glistening with glandular droplets and with margins curled upward. Glabrous scapes rise from the centre, each with one flower. The flower is white, with violet-blue tips to the corolla lobes and yellow hairs in the throat — the plan of the hirtiflora group to which the species belongs. The diagnostic characters lie not in colour but in the precise shape of flower and leaf, and were established with geometric methods. Reliable measurements for plant, corolla and spur were not freely available for this guide.
Similar species
This is the heart of the matter: the species stands extremely close to Pinguicula hirtiflora, which grows in the same Campanian mountains. The original separation rested on subtle differences in flower and leaf shape, measured by geometric morphometrics. Shortly afterwards, molecular work on the Italian butterworts showed that P. lavalvae coincides genetically with Campanian P. hirtiflora, and that the plant may therefore fall within that species' range of variation. The Italian flora portals accordingly flag the taxon as doubtful.
The trap and how it works
A flypaper trap in one of the wetter corners of southern Italy. The leaf bears stalked glands with an adhesive droplet and sessile glands releasing digestive enzymes once prey is lying on them. In a spring habitat the supply is generous: mosquitoes, midges, gnats and springtails hang in clouds over the water. After a catch the leaf margin rolls over the prey, so the digestive fluid stands in a shallow dish instead of running off the wet wall. On flushed limestone there is next to no nitrogen to be had from the substrate; the catch is the main supply.
Habitat and ecology
Permanently wet calcareous ground in the headwater basin of a Campanian mountain river: dripping rock faces, flushes along streams and the wet zone around springs. The plant roots in crevices, in moss cushions and in freshly deposited tufa, in shaded cool corners of the valley. The Monti Picentini are one of the main water-supply catchments of southern Italy, and that bears directly on these sites: every spring captured for the water supply is one potential site fewer.
Distribution and elevation
The Monti Picentini in Campania, southern Italy, with the described occurrence in the Sabato valley. The range is extremely small and covers a handful of spring localities within one mountain chain. Our own species list gives only 'Italy'; for a plant with this distribution that is far too coarse. Whether the population ultimately stands as a species of its own or is returned to P. hirtiflora changes nothing about the fact that a very limited number of wet places is involved.
- Native
Forms and variation
No wild varieties are recognised. The uncertainty sits a level higher: the taxon itself is flagged as doubtful in the Italian flora portals, with reference to the molecular work placing it within the variation of P. hirtiflora. For the field-guide reader that changes little — the plants are there, on the same wet walls, and are worth the same whether called species or form — but anyone consulting literature and databases should expect the taxon under both names.
Where and when to see it
Spring, when the springs run highest and the walls drip everywhere. From the valley, follow a stream upward to its source and search the shaded, wet rock faces there. The rosettes often sit above eye level, so look up and use binoculars. Do not walk through the wet flush at the foot of the wall and do not step onto the fresh tufa crust; it bears no weight and the plant roots in precisely that. For this contested taxon a good photograph of flower, leaf and fruit plus the locality is worth more than a collected plant.
Conservation status
On the global Red List the situation is not one of concern. That figure is dwarfed, however, by what is said about these plants nationally: on the Italian red list the taxon is listed as Critically Endangered, on the grounds of its minute range and few localities. The contrast is explained by the global picture here largely following the much broader P. hirtiflora. The threats are the capping of springs in an important water-supply catchment, falling discharge in longer droughts, and trampling around springs. CITES does not apply.
Scientific name
Pinguicula lavalvae | Innangi & Izzo, 2015
Described by Michele Innangi and Antonietta Izzo in 2014/2015 (published online 2014, in print 2015), in Plant Biosystems 149: 990–999, with the aid of geometric morphometrics. The species is a narrow endemic of the Sabato Valley, in the Picentini Mountains in Campania, southern Italy. The available sources do not explicitly state who the species name honours; the Italian botanist Vincenzo La Valva (1947–2014), who specifically studied the flora of the Campania Apennines and the Picentini Mountains, is a likely candidate.
World Checklist of Vascular Plants (WCVP), via Plants of the World Online (POWO), Royal Botanic Gardens, Kew.