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Pinguicula moaensis
The Sierra de Moa in the far north-east of Cuba is one of the strangest landscapes in the Caribbean: a rolling plateau of red-brown, metal-rich serpentine soil covered with low, hard scrub called charrascal and cut by crystal-clear streams. Pinguicula moaensis is the butterwort of exactly those stream banks — a plant whose whole existence depends on the narrow strip where the water meets the scrub.
No photograph of this species under a Creative Commons licence or in the public domain is in the guide yet.
Identification
A flat rosette of entire, fleshy leaves lying against wet bank soil or bare rock, with a dense glandular coat that lights up like dew in raking light. From the centre rise slender, glandular-hairy scapes, each with a single two-lipped, spurred flower. The rosette is small and hides easily in the low scrub; the best field mark is the wet, glossy leaf surface, which stands out from the dull, hard leaves of almost every shrub around it. The scape rises only a little above the rosette, so the flower stands just above the wet ground. That stalk too is set with glandular hairs, clearly visible with a hand lens and a good way of separating the plant from germinating grasses.
Similar species
The same area holds closely related butterworts, among them Pinguicula jaraguana, which shares some of the streams but has been collected higher, around six hundred metres, and P. infundibuliformis, which comes from cloud forest on the plateau at Mina Iberia. Without flowers these species cannot be told apart with certainty. In practice that means recording the exact elevation, the stream and the vegetation, and photographing the flower from the side. Determination afterwards belongs with someone holding the descriptions.
The trap and how it works
As a flypaper trap the species is standard: stalked glands with a sticky droplet, sessile glands that release enzymes only once prey rests on them, and a leaf margin rolling slowly towards the prey so the fluid pools in a shallow dish. Along a stream in open scrub the supply is large and constant — midges and craneflies swarm above the water all year. Because serpentine yields almost no available nitrogen or phosphorus, that catch is not a supplement here but the principal source of nutrition.
Habitat and ecology
Serpentine scrub along stream banks: that is how briefly and precisely the labels put it. The plants sit on the permanently wet strip where the stream meets the scrub, on bare rock and on thin, sodden soil. Serpentine means much magnesium, nickel and chromium and little calcium, nitrogen and phosphorus — toxic for most plants, but an opportunity for a carnivore, which takes its minerals from insects anyway. Labelled finds lie around five hundred metres.
Distribution and elevation
Endemic to Cuba and confined to the Moa–Baracoa massif in Holguín and Guantánamo provinces: the cuchillas de Moa near Mina Mercedita, the headwaters of the río Jiguaní, the Sierra de Moa near La Melba, and in Guantánamo the Palenque area along the arroyo Frijol. That is a network of stream valleys within a single range, and therefore a small and irreplaceable area. The region also holds a large share of Cuba's serpentine endemics and the country's biggest nickel mines.
- Native
Forms and variation
No wild subspecies or varieties are recognised. As in almost all butterworts of this massif the breadth of variation has not been properly studied: the known populations are spread over several streams, and recent work on related species has shown that what passed for one species may split. What stands out most in the field is the size difference between rosettes on permanently wet rock and those on bank soil that dries between showers. The Moa serpentine landscape is also anything but uniform: one stream cuts through bare rock, another through a thicker layer of weathered soil, and such differences translate into the growth rate and size of the plants.
Where and when to see it
Walk the stream with your eye on the waterline. Search wet rock slabs, seeping bank faces and the mossy edge the water reaches at high flow. Raking morning light makes the glandular coat visible and betrays whole groups at once. The entire area is either protected land or mining concession; go with a guide, respect access rules and leave the plants standing. In this company collecting yields nothing a good photograph does not.
Conservation status
The species has not been assessed for the global IUCN Red List and is not listed in CITES. What is known: an eastern Cuban endemic of a handful of serpentine streams in the region where Cuba's largest nickel extraction takes place. For a plant wholly dependent on the bank strip of a stream, excavation, road building, sediment load and changing run-off are not theoretical threats. There is no international category because nobody has carried out the assessment, not because the situation is reassuring. The good news is that part of the sites fall inside protected land and that the inhospitable terrain limits access of its own accord.
Scientific name
Pinguicula moaensis | Casper, 2019
Described by Siegfried Jost Casper in 2019, in Englera 35: 1–126, based on material collected on 25 February 1979. The type locality lies in the municipality of Moa, Sierra de Moa, La Melba, along the Jaragua rivulet, in Holguín Province, Cuba. The name "moaensis" refers to the locality: the municipality of Moa and the Sierra de Moa mountains in eastern Cuba.
World Checklist of Vascular Plants (WCVP), via Plants of the World Online (POWO), Royal Botanic Gardens, Kew.