All species › Lamiales › Bladderwort family › Pinguicula bustamanta
Pinguicula bustamanta
A small white-flowered butterwort of the limestone rocks around Bustamante in Nuevo León, from which it takes its name. Pinguicula bustamanta was described only in 2020 and stands out for what it does not do: it forms no separate winter rosette, as most Mexican species do, but keeps the same leaves all year and can flower continuously. That makes it one of the few butterworts of north-eastern Mexico that never quite leave the stage.
No photograph of this species under a Creative Commons licence or in the public domain is in the guide yet.
Identification
A small, sparse rosette of only 4 to 6(8) leaves, obovate-spathulate to oblong-spathulate, 11 to 30 mm long and 5 to 17 mm wide, with the usual glistening glandular droplets on the upper surface. Winter and summer leaves cannot be told apart: the plant has a single leaf type. Each plant carries 1 to 4(8) slender scapes (30)40 to 80 mm tall. The flower is small — 10 to 14 mm long including the spur — and white, sometimes with lilac lobe margins; the spur is short and straight, 2 to 4.5 mm. In the field the species was collected in flower in May, and in cultivation it proves to flower almost without interruption, which fits the absence of a true resting period.
Similar species
The closest relative is Pinguicula lilacina, and it looks much alike. The difference lies in lifespan and rhythm: P. lilacina is annual or short-lived and flowers in a defined period, whereas P. bustamanta is perennial and keeps flowering. In case of doubt the seed decides — striate testa in this species, alveolate in P. lilacina — but that is a microscope character, not a field one. The same country holds larger-flowered species such as P. gracilis and the gypsum-dwelling butterworts of Nuevo León; all differ in flower size or in habitat.
The trap and how it works
A flypaper trap of modest size but working on the same principle as in the large species. The upper leaf surface carries stalked glands with a sticky droplet and sessile glands that release digestive enzymes only on contact with prey; a captured insect sinks into the layer of droplets and over the course of a day the leaf margin bends slightly across it. In the dry, warm limestone country around Bustamante the catch is correspondingly small: little flies, midges and ants moving along the damp foot of the rock. Because the plant keeps its leaves all year, it also feeds all year — an advantage where insect supply varies strongly from month to month.
Habitat and ecology
Limestone rock at about 900 m, in the transition from submontane scrub to low oak woodland. The plants sit on and among the limestone (R2) where water seeps down the face after rain and lingers in the crevices (R1), in the half shade of shrubs and low oaks (B5). This is not a permanently wet habitat like a cloud forest but a dry district in which the plant depends on small, reliably damp spots: the foot of an overhang, a north-facing crevice, a fissure where condensation collects. It is precisely that difference of scale that makes such species so vulnerable.
Distribution and elevation
Endemic to the municipality of Bustamante in the Mexican state of Nuevo León, in the limestone ranges of the Sierra Madre Oriental. Our finding differs here from the guide's species list, which gives Durango: the protologue places the species unambiguously at Bustamante, Nuevo León, and the epithet refers to that same place. The known range is remarkably small — in effect a single limestone massif — and the species is so recently described that further finds in the surrounding mountains cannot be ruled out; for now it is known from the type area only.
- Native
Forms and variation
No wild varieties have been described, which is hardly to be expected in a species known from one limestone massif. What varies is the amount of lilac in the flower margin — from pure white to clearly lilac-edged — and the number of scapes, which can reach eight in well-grown plants. Because the plant forms no winter rosette, it also lacks the variation in winter form that underlies many named forms in other Mexican butterworts. No natural hybrids are reported.
Where and when to see it
May is the month in which the species has been found flowering in the field, but as it has no strict flowering period you stand a chance outside it too. Search along the foot of limestone faces and in the canyons around Bustamante, where water runs down the rock after a shower and mosses and ferns grow. The plant is small and the flower barely a centimetre and a half: walk slowly and look for white against dark grey limestone. Go after rain; both the site and the glandular droplets are then at their best. Stay on the path — the foot of the rock is exactly the zone where the plants grow.
Conservation status
The species has not been assessed for the global IUCN Red List and is not listed in CITES; the original description makes no statement on its conservation status. What exists is nonetheless worryingly limited: one known site in one municipality, a species named only in 2020, and a habitat — damp limestone crevices in otherwise dry country — that a modest amount of work (road widening, quarrying, recreational pressure in the canyon) could remove entirely. Newly described Mexican butterworts also tend to appear in the plant trade within a few years. The absence of a category here follows purely from how recently the species was described.
Scientific name
Pinguicula bustamanta | Zamudio & Nevárez, 2020
Described by Sergio Zamudio and Manuel Nevárez de los Reyes in 2020, in Phytoneuron 2020-28: 1–10. The type area lies in the Sierra de Gomas, in the municipality of Bustamante in the Mexican state of Nuevo León, at around 900 metres elevation. The species name bustamanta refers directly to the municipality of Bustamante, where the species was discovered.
World Checklist of Vascular Plants (WCVP), via Plants of the World Online (POWO), Royal Botanic Gardens, Kew.