Pinguicula zamudioana — Vorstman's Guide to the Carnivorous Plants

Identification

A homophyllous rosette with only one leaf type — the so-called summer leaves — which the plant keeps year-round. The leaves are light green and have glabrous petioles, a character named in the description. The flower is pink. For the exact dimensions of rosette, leaf, scape, flower and spur we could not obtain a freely available, testable statement from the original description; those fields have therefore been left empty on the fact card. The species belongs to section Orcheosanthus, the group of large-flowered Mexican butterworts, and flowering is not bound to a season: the plant is in constant growth and blooms all year.

Similar species

The protologue sets the species against Pinguicula oblongiloba and Pinguicula michoacana, both also from western Mexico and both in section Orcheosanthus. The distinction is unusually easy to make in the field, provided you look in the dry season: those two then form a compact winter rosette of thick non-carnivorous leaves, whereas P. zamudioana keeps its ordinary light green leaves and simply goes on flowering. A large-flowered butterwort found in full growth in Jalisco in December or January is therefore a strong pointer. The glabrous petioles are a second character.

The trap and how it works

The rosette is in service all year, which is unusual for a Mexican butterwort. The leaves carry stalked glands with a clear sticky droplet and sessile glands that release digestive enzymes only once prey lies on the leaf; the margin then bends slightly over the catch. Because the plant never rests, it need not build reserves for a dry period and can turn the proceeds of the catch straight into growth and flowers — which explains why it can bloom without interruption. The habitat supplies the condition for that: permanent moisture.

Habitat and ecology

The species grows exclusively on calcium concretions: porous lime deposits formed where calcareous water emerges from the rock and leaves its lime behind as it evaporates (R2). Such places are permanently damp because the water keeps coming (R1), which explains why the plant needs no drought rest. They are at the same time very small sites — a seepage spot is often no more than a few square metres — scattered through the landscape like islands. The strong attachment to this substrate is named in the description as the factor limiting the species' distribution.

Distribution and elevation

Endemic to western Mexico, in the state of Jalisco — in agreement with the entry in our species list. This is a species bound to a rare and small-scale habitat type, so the range is fragmented by definition: where there are no calcium concretions there is no plant. Western Mexico is less thoroughly explored botanically than the east and south, and several butterworts have been described from Jalisco and adjoining states in recent years; further finds at comparable seepage sites in the mountains of Jalisco are quite conceivable.

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 square is the only one-degree cell — 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. It shows where the species has been seen, not where it occurs: an empty square means nothing.

Forms and variation

No wild varieties are recognised. The species was described only in 2018 and is known from a limited number of sites, so there is too little material on which to base forms. What is interesting is that the absence of a winter rosette is a fixed character here and not a response to the site: where related species in cultivation sometimes skip their winter rest under constant moisture, in P. zamudioana that is the normal state in the wild. The difference between a heritable character and a response to conditions is exactly what naming forms turns on. No natural hybrids are reported.

Where and when to see it

This species can be found all year, which makes it an exception among Mexican butterworts; searching in the dry season has the added advantage that related species are then invisible and confusion is ruled out. Look for the lime deposits themselves: pale porous crusts on rock where water emerges, often marked by a permanently wet streak and by mosses and small ferns. The pink flowers stand above the rosette and show from a few metres away. Do not touch the lime crust — it is brittle and the plants root shallowly in it.

Conservation status

The species has not been assessed for the global IUCN Red List and is not listed in CITES. What is known gives the profile of a vulnerable species: described only in 2018, endemic to one state, and wholly tied to a rare and extremely small-scale habitat type. Lime deposits at seepage points vanish with any intervention in the water regime — a capped spring, a borehole, a diverted drainage — and they often lie in areas without protected status. A large-flowered, continuously flowering butterwort is moreover an attractive target for collectors. A category is missing because no assessment has ever been made, not because the picture is reassuring.

Scientific name

Pinguicula zamudioana | Juárez & Muñiz-Castro, 2018

Described by D. Juárez and E. Muñiz-Castro in 2018, in the article "Pinguicula zamudioana (Lentibulariaceae), a new species endemic to western Mexico", Phytotaxa 372(4): 243–255. The species is endemic to western Mexico (the Nueva Galicia region, including Jalisco state). The species name honours Sergio Zamudio Ruiz, "who has enthusiastically dedicated himself to the study of the genus Pinguicula in Mexico and Central America", according to the original description.

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