Giant Butterwort

Taxonomy

Family:	Lentibulariaceae
Genus:	Pinguicula
Order:	Lamiales

Overview

Pinguicula gigantea is a Mexican butterwort from the steep slopes around San Bartolomé Ayautla in Oaxaca, with some of the largest leaves in the genus, up to about 6 inches (16 cm) long. Unusually, both surfaces of its leaves are sticky and catch insects.

P. gigantea is a perennial rosette plant with a short, simple stem and numerous fibrous roots. Its semi-erect, bright green leaves are oblong to obovate with rounded tips, 60-145 mm (up to 165 mm) long and 40-70 mm (up to 80 mm) wide, and are densely covered on both sides with sessile and stalked glands. The epithet gigantea refers to these large leaves.

Most Mexican butterworts alternate between carnivorous summer leaves and a compact rosette of succulent winter leaves. P. gigantea is barely heterophyllous: its winter leaves, 35-60 mm long, differ from the summer leaves mainly in size, and it forms no distinct winter rosette.

One to five flower stalks, 15-18.5 cm (6-7 in) tall, each carry a single flower 28-33 mm long including the spur. The corolla has nearly equal lobes, pale purple-violet to whitish lilac with a violet margin, and a green tube with violet lines. Forms with blue, white and dark purple flowers are grown. Hans Luhrs placed the species in section Agnata, related to P. agnata.

Geographic Information

Native Region: Near San Bartolomé Ayautla, Oaxaca, Mexico

Climate Zones: Tropical, with a wet and a dry season

The type locality is on steep slopes near San Bartolomé Ayautla, Oaxaca, at 500-800 m (1,600-2,600 ft). Its discoverer, Alfred Lau, found it on fully exposed rock walls in hot tropical sun, growing with Tillandsia streptophylla, and believed it grew along the south side of the steep walls of the Río Uruapan valley up to above Ayautla. Like other Mexican butterworts it experiences a wet season and a dry season.

Physical Characteristics

Mature Size: Leaves 2.4-5.7 in (6-14.5 cm) long, occasionally 6.5 in (16.5 cm); flower stalks 6-7 in (15-18.5 cm)

Growth Rate: Moderate

Trap Type: Flypaper Trap

The leaves are densely covered with sessile and stalked glands that secrete a sticky mucilage. Small insects such as fungus gnats stick to the surface and are digested on the leaf. Unlike almost all other butterworts, P. gigantea has stalked glands densely on both the upper and lower leaf surfaces, so its semi-erect leaves catch prey on both sides.

Care Guide

Light Requirements

Bright light: a sunny window, greenhouse or plant lights. With heterophyllous Mexican species, slowly changing day length matters more than the total number of hours.

Natural or seasonally adjusted day length daily

Water Requirements

Type: Low-mineral water; a salt crust on the soil surface is a sign to repot

Method: Mexican butterworts are not bog plants. A common method is to stand pots in up to 2 cm of water in spring and summer and let the tray dry out for about a week between waterings in winter. Growers in humid greenhouses water from above, avoiding the rosette, and let the mix dry slightly between waterings.

Frequency: Wet season: keep moist; dry season: let the mix dry between waterings

Humidity: Warm and humid while in active growth

Soil

A well-drained, mostly mineral mix. The ICPS suggests equal parts peat, coarse sand and perlite with dolomitic lime added for house plants; greenhouse growers often use pure mineral mixes of perlite, vermiculite and sand.

pH: Alkaline, as for most Mexican Pinguicula

Temperature

Summer: Warm; normal house temperatures

Winter: Cooler and drier

Feeding

Frequency: Usually unnecessary; catches fungus gnats and other small insects

Mexican Pinguicula appreciate light fertilization, such as a small amount of fertilizer in the water. It is very easy to over-fertilize plants standing in trays and burn them.

Propagation

Methods: Leaf pullings: carefully remove whole leaves including the white base, where new plantlets form. Seed: the flowers cannot pollinate themselves, so transfer pollen by hand, ideally between two flowering plants; seed is slow to reach maturity.

Difficulty: Easy

Beginner Tips

Treat it like a succulent house plant that likes insects: bright light, a free-draining mineral mix, and less water in winter.

Troubleshooting

Salt crust on the soil or roots crowded by old leaf thatch: repot. Plant declining after a fungicide treatment: Pinguicula do not tolerate fungicides.

Growing Tips

No fungicides, ever Troubleshooting

Fungicides, even cinnamon, kill Pinguicula. Prevent problems with good air movement and a sand top layer instead.

Pull the whole leaf Advanced

For new plants, peel off entire leaves including the pale base and lay them on the mix. The plantlets grow from that base.

Interesting Facts

Its leaves are among the largest in the genus.
It catches insects on both sides of its leaves, a trait shared by very few other butterworts.
It was distributed in cultivation under the name Pinguicula 'Ayautla' before it was formally described.
Leaves pulled from the rosette, including the white base, sprout new plantlets.

History

The botanist Alfred Lau collected the plant in 1987 near San Bartolomé Ayautla in the state of Oaxaca, and told the story of its discovery in the newsletter of the International Pinguicula Study Group in 1993. Plants were raised from seed in cultivation, and in December 1995 Hans Luhrs described the species in the journal Phytologia, from cultivated plants and Lau's habitat photographs. The holotype is deposited in the herbarium TEX.

Before then the plant circulated among growers as Pinguicula 'Ayautla', a name Peter D'Amato used in The Savage Garden (1998) that is now treated as a synonym of P. gigantea. Luhrs noted that its uniform leaves fit section Agnata imperfectly; later reclassifications merged several Mexican sections, including Agnata, into section Temnoceras.

Sources

Frequently asked questions

Bright light: a sunny window, greenhouse or plant lights. With heterophyllous Mexican species, slowly changing day length matters more than the total number of hours. Aim for about Natural or seasonally adjusted day length of light a day.

Low-mineral water; a salt crust on the soil surface is a sign to repot. Mexican butterworts are not bog plants. A common method is to stand pots in up to 2 cm of water in spring and summer and let the tray dry out for about a week between waterings in winter. Growers in humid greenhouses water from above, avoiding the rosette, and let the mix dry slightly between waterings.

A well-drained, mostly mineral mix. The ICPS suggests equal parts peat, coarse sand and perlite with dolomitic lime added for house plants; greenhouse growers often use pure mineral mixes of perlite, vermiculite and sand. Soil pH: Alkaline, as for most Mexican Pinguicula.

It does not need a dormancy. Winter temperatures: Cooler and drier.

Mexican Pinguicula appreciate light fertilization, such as a small amount of fertilizer in the water. It is very easy to over-fertilize plants standing in trays and burn them. How often: Usually unnecessary; catches fungus gnats and other small insects.

Near San Bartolomé Ayautla, Oaxaca, Mexico. The type locality is on steep slopes near San Bartolomé Ayautla, Oaxaca, at 500-800 m (1,600-2,600 ft). Its discoverer, Alfred Lau, found it on fully exposed rock walls in hot tropical sun, growing with Tillandsia streptophylla, and believed it grew along the south side of the steep walls of the Río Uruapan valley up to above Ayautla.

Leaf pullings: carefully remove whole leaves including the white base, where new plantlets form. Seed: the flowers cannot pollinate themselves, so transfer pollen by hand, ideally between two flowering plants; seed is slow to reach maturity.

Salt crust on the soil or roots crowded by old leaf thatch: repot. Plant declining after a fungicide treatment: Pinguicula do not tolerate fungicides.

Yes. It is one of the easier carnivorous plants if its light, water and soil needs are met.

Carnivoras sells Giant Butterwort in Mexico. See the plants available on this page.