{{short description|Genus of flowering plants in the family Lentibulariaceae}} {{Distinguish|Pinguecula}} {{Automatic taxobox |image = Pinguicula_moranensis.jpg |image_caption = ''[[Pinguicula moranensis]]'' |taxon = Pinguicula |authority = [[Carl Linnaeus|L.]] |subdivision_ranks = Species |subdivision = 126, see [[List of Pinguicula species|separate list]]. |subdivision_ref = <ref name = powo>{{cite web |title=''Pinguicula'' L. |url=https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:30014019-2 |website=[[Plants of the World Online]] |publisher=[[Royal Botanic Gardens, Kew]] |access-date=26 April 2025}}</ref> |synonyms = *''Brandonia'' {{small|Rchb.}} *''Isoloba'' {{small|Raf.}} *''Pinguicola'' {{small|Zumagl.}} |synonyms_ref = <ref name = powo/> }}
'''''Pinguicula''''', commonly known as '''butterworts''', is a genus of [[carnivorous plant|carnivorous]] [[flowering plant]]s in the family [[Lentibulariaceae]]. They use sticky, glandular leaves to lure, trap, and digest insects in order to supplement the poor mineral nutrition they obtain from the environment. 126 species are currently accepted.<ref name = powo/> 13 are native to Europe, 9 to North America, and some to northern Asia. The largest number of species is in South and Central America.
==Etymology== The name ''Pinguicula'' is derived from a term coined by [[Conrad Gesner]], who in his 1561 work entitled ''Horti Germaniae'' commented on the glistening leaves: ''"propter pinguia et tenera folia…"'' (Latin ''pinguis'', "fat"). The common name "butterwort" reflects this characteristic.<ref>{{cite web |title=How to Grow Your Indoor Butterworts (Pinguicula) |url=https://www.ukhouseplants.com/plants/pinguicula-butterworts |website=UKHouseplants |access-date=11 March 2022 |language=en}}</ref>
==Characteristics== The majority of ''Pinguicula'' are [[perennial plant]]s. The only known [[annual plant|annuals]] are [[Pinguicula sharpii|''P. sharpii'']], [[Pinguicula takakii|''P. takakii'']], [[Pinguicula crenatiloba|''P. crenatiloba'']], and [[Pinguicula pumila|''P. pumila'']]. All species form stemless [[Rosette (botany)|rosettes]].
===Habitat=== [[File:PinguiculaCyclosectaWinter.jpg|thumb|180px|right|Winter rosette of ''[[Pinguicula cyclosecta]]'' (non-carnivorous phase)]] [[File:Pinguicula cyclosecta summer.jpg|thumb|180px|right|Summer rosette of ''[[Pinguicula cyclosecta]]'' (carnivorous phase)]] Butterworts can be divided roughly into two main groups based on the climate in which they grow; each group is then further subdivided based on [[Morphology (biology)|morphological]] characteristics. Although these groups are not [[cladistics|cladistically]] supported by genetic studies,<ref name="cieslak2005">{{cite journal |vauthors=Cieslak T, Polepalli JS, White A, Müller K, Borsch T, Barthlott W, Steiger J, Marchant A, Legendre L | title=Phylogenetic analysis of ''Pinguicula'' (Lentibulariaceae): chloroplast DNA sequences and morphology support several geographically distinct radiations | journal=[[American Journal of Botany]] | volume=92| year=2005| pages=1723–1736 | doi= 10.3732/ajb.92.10.1723 | issue=10 | pmid=21646090| doi-access=free | bibcode=2005AmJB...92.1723C }}</ref> these groupings are nonetheless convenient for horticultural purposes.
Tropical butterworts form somewhat compact winter rosettes composed of fleshy leaves or retain carnivorous leaves year-round.<ref>{{Cite web|url=https://www.britannica.com/plant/carnivorous-plant|title=Carnivorous plant {{!}} botany|website=Encyclopedia Britannica|language=en|access-date=2020-03-01}}</ref> They are typically located in regions where water is least seasonally plentiful, as too damp soil conditions can lead to rotting. They are found in areas in which nitrogenous resources are known to be in low levels, infrequent or unavailable, due to acidic soil conditions.
[[Temperate]] species often form tight buds (called [[Hibernaculum (botany)|hibernacula]]) composed of scale-like leaves during a winter [[dormancy]] period. During this time the roots (with the exception of [[Pinguicula alpina|''P. alpina'']]) and carnivorous leaves wither.<ref name="legendre2000">{{cite journal | author=Legendre L | title=The genus ''Pinguicula'' L. (Lentibulariaceae): an overview | journal=Acta Botanica Gallica | volume=141 | issue=1 | year=2002 | pages=77–95 | url=http://www.pinguicula.org/pages/culture/Overview.htm}}</ref> Temperate species flower when they form their summer rosettes while tropical species flower at each rosette change.
Many butterworts cycle between rosettes composed of carnivorous and non-carnivorous leaves as the seasons change, so these two ecological groupings can be further divided according to their ability to produce different leaves during their growing season. If the growth in the summer is different in size or shape to that in the early spring (for temperate species) or in the winter (tropical species), then plants are considered [[heterophyllous]]; whereas uniform growth identifies a [[homophyllous]] species.
This results in four groupings:
*'''Tropical butterworts''': species which do not undergo a winter dormancy but continue to alternately bloom and form rosettes. **'''''Heterophyllous tropical species''''': species that alternate between rosettes of carnivorous leaves during the warm season and compact rosettes of fleshy non-carnivorous leaves during the cool season. Examples include [[Pinguicula moranensis|''P. moranensis'']], [[Pinguicula gypsicola|''P. gypsicola'']], and [[Pinguicula laxifolia|''P. laxifolia'']]. **'''''Homophyllous tropical species''''': these species produce rosettes of carnivorous leaves of roughly uniform size throughout the year, such as [[Pinguicula gigantea|''P. gigantea'']]. *'''Temperate butterworts''': these plants are native to climate zones with cold winters. They produce a winter-resting bud ([[Hibernaculum (botany)|hibernaculum]]) during the winter. **'''''Heterophyllous temperate species''''': species where the vegetative and generative rosettes differ in shape and/or size, as seen in [[Pinguicula lutea|''P. lutea'']] and [[Pinguicula lusitanica|''P. lusitanica'']]. **'''''Homophyllous temperate species''''': the vegetative and generative rosettes appear identical, as exhibited by [[Pinguicula alpina|''P. alpina'']], [[Pinguicula grandiflora|''P. grandiflora'']], and [[Pinguicula vulgaris|''P. vulgaris'']].
===Roots=== The [[root|root system]] of ''Pinguicula'' species is relatively undeveloped. The thin, white roots serve mainly as an anchor for the plant and to absorb moisture (nutrients are absorbed through carnivory). In temperate species these roots wither (except in [[Pinguicula alpina|''P. alpina'']]) when the [[Hibernaculum (botany)|hibernaculum]] is formed. In the few [[epiphytic]] species (such as [[Pinguicula lignicola|''P. lignicola'']]), the roots form anchoring suction cups.
===Leaves and carnivory=== [[File:Pinguicula with prey.JPG|thumb|210px|left|A fly trapped on a butterwort leaf. Glandular hairs are visible.]] The leaf blade of a butterwort is smooth, rigid, and succulent, usually bright green or pinkish in colour. Depending on species, the leaves are between 2 and 30 cm (1–12") long. The leaf shape depends on the species, but is usually roughly [[Leaf#Terminology|obovate]], [[Leaf#Terminology|spatulate]], or [[Leaf#Terminology|linear]].<ref>{{Cite web|url=https://www.gardeningknowhow.com/houseplants/butterwort/how-to-grow-butterworts.htm|title=Carnivorous Butterwort Care – How To Grow Butterworts|website=Gardening Know How|date=25 March 2013 |language=en-US|access-date=2020-03-01}}</ref> They can also appear yellow in color with a soft feel and a greasy consistency to the leaves.
[[File:Pinguicula vector en.svg|right|250px|Vector graphic of the trapping and digestive features of a ''Pinguicula'' leaf]] Like all members of the family [[Lentibulariaceae]], butterworts are carnivorous.<ref name="pmid28313028">{{Cite journal|journal=Oecologia|year=1990|doi=10.1007/bf00329762|pmid=28313028|last1=Zamora|first1=R.|title=The feeding ecology of a carnivorous plant (Pinguicula nevadense): Prey analysis and capture constraints |volume=84|issue=3|pages=376–379|bibcode=1990Oecol..84..376Z |s2cid=8038140}}</ref> The mechanistic actions that these plants use to lure and capture prey is through a means of sticky or adhesives substances that are produced by mucilage secreted by glands located on the leaf's surface. In order to catch and digest insects, the leaf of a butterwort uses two specialized glands which are scattered across the leaf surface (usually only on the upper surface, with the exception of [[Pinguicula gigantea|''P. gigantea'']] and ''[[Pinguicula longifolia|P. longifolia ssp. longifolia]]'').<ref name="legendre2000" /> [[File:Pinguicula esseriana2.jpg|thumb|239x239px|Pinguicula esseriana in the greenhouse of the Kharkiv Botanical Garden]] One is termed a ''peduncular gland'', and consists of a few [[secrete|secretory]] cells on top of a single stalk cell. These cells produce a [[mucilage|mucilaginous]] secretion which forms visible droplets across the leaf surface. This wet appearance probably helps lure prey in search of water (a similar phenomenon is observed in the [[Drosera|sundews]]). The droplets secrete limited amounts of digestive enzymes, and serve mainly to entrap insects. On contact with an insect, the peduncular glands release additional mucilage from special reservoir cells located at the base of their stalks.<ref name="legendre2000" /> The insect will begin to struggle, triggering more glands and encasing itself in mucilage. Some species can bend their leaf edges slightly by [[thigmotropism]], bringing additional glands into contact with the trapped insect.<ref name="legendre2000" />
The second type of gland found on butterwort leaves are ''sessile glands'' which lie flat on the leaf surface. Once the prey is entrapped by the peduncular glands and digestion begins, the initial flow of nitrogen triggers enzyme release by the sessile glands.<ref name="legendre2000" /> These enzymes, which include [[amylase]], [[esterase]], [[phosphatase]], [[protease]], and [[ribonuclease]] break down the digestible components of the insect body. These fluids are then absorbed back into the leaf surface through [[Plant cuticle|cuticular]] holes, leaving only the [[chitin]] [[exoskeleton]] of the larger insects on the leaf surface.
The holes in the cuticle which allow for this digestive mechanism also pose a challenge for the plant, since they serve as breaks in the [[Plant cuticle|cuticle]] (waxy layer) that protects the plant from [[desiccation]]. As a result, most butterworts live in humid environments.
[[File:Pinguicula vulgaris flower (side view) - Keila.jpg|thumb|180px|right|Flower of ''P. vulgaris'']] Butterworts are usually only able to trap small insects and those with large wing surfaces. They can also digest [[pollen]] which lands on their leaf surface. The secretory system can only function a single time, so that a particular area of the leaf surface can only be used to digest insects once.<ref name="legendre2000" />
Unlike many other carnivorous plant species, butterworts do not appear to use [[jasmonates]] as a control system to switch on the production of digestive enzymes. Jasmonates are involved in the butterwort's defense against attacking insects, but not in its response to prey.<ref name="Pain">{{cite journal |last1=Pain |first1=Stephanie |title=How plants turned predator |journal=Knowable Magazine |date=2 March 2022 |doi=10.1146/knowable-030122-1|doi-access=free |url=https://knowablemagazine.org/article/living-world/2022/how-plants-turned-predator |access-date=11 March 2022|url-access=subscription }}</ref><ref name="Hedrich">{{cite journal |last1=Hedrich |first1=Rainer |last2=Fukushima |first2=Kenji |title=On the Origin of Carnivory: Molecular Physiology and Evolution of Plants on an Animal Diet |journal=Annual Review of Plant Biology |date=17 June 2021 |volume=72 |issue=1 |pages=133–153 |doi=10.1146/annurev-arplant-080620-010429 |pmid=33434053 |s2cid=231595236 |issn=1543-5008|doi-access=free |bibcode=2021AnRPB..72..133H }}</ref><ref name="Kocáb"/> Of the eight enzymes identified in the digestive secretions of butterworts, [[alpha-amylase]] appears to be unique when compared to other carnivorous plants. This research suggests that butterwort may have co-opted a different set of genes in its development of carnivory.<ref name="Kocáb">{{cite journal |last1=Kocáb |first1=Ondřej |last2=Jakšová |first2=Jana |last3=Novák |first3=Ondřej |last4=Petřík |first4=Ivan |last5=Lenobel |first5=René |last6=Chamrád |first6=Ivo |last7=Pavlovič |first7=Andrej |title=Jasmonate-independent regulation of digestive enzyme activity in the carnivorous butterwort Pinguicula × Tina |journal=Journal of Experimental Botany |date=22 June 2020 |volume=71 |issue=12 |pages=3749–3758 |doi=10.1093/jxb/eraa159 |pmid=32219314 |pmc=7307851 }}</ref>
=== Flowers === [[File:Pinguicula hybrid ne.JPG|thumb|180px|right|The flower of a hybrid butterwort]] {{Unreferenced section|date=April 2020}} As with almost all [[carnivorous plants]], the flowers of butterworts are held far above the rest of the plant by a long stalk, in order to reduce the probability of trapping potential pollinators.<ref>{{Cite web |title=Common Butterwort (Pinguicula vulgaris) |url=https://easyscape.com/species/Pinguicula-vulgaris%28Common-Butterwort%29 |access-date=2026-01-20 |website=easyscape.com |language=en}}</ref> The single, long-lasting flowers are [[zygomorphic]], with two lower lip petals characteristic of the [[Lentibulariaceae|bladderwort family]], and a spur extending from the back of the flower. The [[sepals|calyx]] has five sepals, and the petals are arranged in a two-part lower lip and a three-part upper lip.<ref>{{Cite journal |last1=Lustofin |first1=Krzysztof |last2=Świątek |first2=Piotr |last3=Miranda |first3=Vitor F. O. |last4=Płachno |first4=Bartosz J. |date=2020-01-01 |title=Flower nectar trichome structure of carnivorous plants from the genus butterworts Pinguicula L. (Lentibulariaceae) |journal=Protoplasma |language=en |volume=257 |issue=1 |pages=245–259 |doi=10.1007/s00709-019-01433-8 |issn=1615-6102 |pmc=6982637 |pmid=31428856 |bibcode=2020Prpls.257..245L }}</ref> Most butterwort flowers are blue, violet or white, often suffused with a yellow, greenish or reddish tint. ''[[Pinguicula laueana|P. laueana]]'' and the newly described [[Pinguicula caryophyllacea|''P. caryophyllacea'']] are unique in having a strikingly red flowers. Butterworts are often cultivated and hybridized primarily for their flowers.
The shape and colors of butterwort flowers are distinguishing characteristics which are used to divide the genus into subgenera and to distinguish individual species from one another.<ref>{{Cite web |title=On the infrageneric classification of Pinguicula |url=https://cpn.carnivorousplants.org/articles/CPNv50n4p174_188.pdf}}</ref>
=== Fruit and seed === The round to egg-shaped [[Capsule (fruit)|seed capsules]] open when dry into two halves, exposing numerous small (0.5–1 mm), brown seeds. If moisture is present the [[silique]] closes, protecting the seed and opening again upon dryness to allow for [[seed dispersal#Wind|wind dispersal]]. Many species have a net-like pattern on their seed surface to allow them to land on water surfaces without sinking, since many non-epiphytic butterworts grow near water sources. The [[haploid]] [[chromosome]] number of butterworts is either n = 8 or n = 11 (or a multiple thereof), depending on species. The exception is ''[[Pinguicula lusitanica|P. lusitanica]]'', whose chromosome count is n = 6.{{Citation needed|date=February 2007}}
=== Diet === The diet will range depending on the taxonomy and size of the prey due to the plant's retention ability. These size limitations are known to be the main element influencing what prey sources this carnivorous plant can access.<ref>{{Cite journal|last=Zamora|first=Regino|date=1990|title=The Feeding Ecology of a Carnivorous Plant (Pinguicula nevadense): Prey Analysis and Capture Constraints|journal=Oecologia|volume=84|issue=3|pages=376–379|doi=10.1007/BF00329762|jstor=4219437|pmid=28313028|bibcode=1990Oecol..84..376Z|s2cid=8038140|issn=0029-8549}}</ref> They can also acquire nourishment from pollen and other plant parts that are high in protein, as other plants can become trapped on their leaves, thus, butterworts are both carnivorous and herbivorous plants.<ref name="pmid28313028" /> The diet consists of several species from the arthropod taxa; the majority of their prey are insects that have wings and are able to fly. The luring, retaining, and seizing of prey is the first steps in the feeding procedure for carnivorous plants; the result of the process is absorption and digestion of nutrients sourced from these food supplies. Pinguicula species do not select their prey, as they passively accumulate them through methods of sticky, adhesive leaves. However, they do have the ability of visual attraction of their colorful leaves, which will increase the likelihood of luring and capturing a specific taxa.<ref>{{Cite web|url=https://www.carnivorous--plants.com/butterworts-plant.html|title=All About the Butterworts Plant|website=www.carnivorous--plants.com|language=en|access-date=2020-03-16}}</ref> {{Better source needed|date=July 2020|reason=website is not peer reviewed or based on any given citations}} Pinguicula capture their food source/ prey by means of the mucilaginous, sticky substances produced by their stalk glands on the top of their leaf. Once the prey has become trapped in the peduncular glands, the sessile glands present will then produce enzymes needed to accomplish digestion and breaking down the digestible regions of the prey for their nutrients; taking in the fluids of the food source by means of cuticular holes present on the leaf's surface.
=== Vegetative propagation === As well as [[sexual reproduction]] by seed, many butterworts can reproduce [[asexual reproduction|asexual]]ly by [[vegetative reproduction]]. Many members of the genus form offshoots during or shortly after flowering (''e.g.'', ''[[Pinguicula vulgaris|P. vulgaris]]''), which grow into new [[Cloning|genetically identical]] adults. A few other species form new [[Offshoot (plant)|offshoots]] using [[stolons]] (''e.g.'', ''[[Pinguicula calyptrata|P. calyptrata]]'', ''[[Pinguicula vallisneriifolia|P. vallisneriifolia]]'') while others form plantlets at the leaf margins (''e.g.'', ''[[Pinguicula heterophylla|P. heterophylla]]'', ''[[Pinguicula primuliflora|P. primuliflora]]'').
== Distribution == [[File:Pinguicula distribution.svg|thumb|240px|right|''Pinguicula'' distribution]] Butterworts are distributed throughout the [[Northern Hemisphere]] ([http://www.pinguicula.org/pages/culture/Overview_fichiers/image002.jpg map]). The greatest concentration of species, however, is in humid mountainous regions of Mexico, Central America and South America, where populations can be found as far south as [[Tierra del Fuego]]. Australia and Antarctica are the only continents without any native butterworts.
While the highest diversity of species is observed in Central America (roughly 50% of butterwort species are found here), the most ancestral species of the genus ''Pinguicula'', both in terms of morphology and molecular reconstruction, are the group of temperate homophyllous species (examples include ''P. lusitanica'', ''P. hirtiflora'', ''[[Pinguicula antartica|P. antartica]]'', ''[[Pinguicula lutea|P. lutea]]'', etc.). Likewise, as other members of [[Lentibulariaceae]] family, ''Pinguicula'' ancestors evolved in South America, where Andean species most probably present as remnants of the ancestral stock of South American ''Pinguicula'' adapted to highland conditions with the rise of the Andes <ref>{{cite web |last=Brittnacher |first=John |year=2010 |title=Evolution of the Lamiales Carnivores |publisher=International Carnivorous Plant Society }}</ref><ref>{{cite book |last1=Lampard |first1=Stan |last2=Gluch |first2=Oliver |last3=Robinson |first3=Alastair S. |last4=Fleischmann |first4=Andreas |last5=Temple |first5=Paul |last6=McPherson |first6=Stewart |last7=Roccia |first7=Aymeric |last8=Partrat |first8=Eric |last9=Legendre |first9=Laurent |year=2016 |title=Pinguicula of Latin America |publisher=Redfern Natural History |isbn=978-1-908787-15-6 }}</ref><ref>{{cite journal |last1=Shimai |first1=H. |last2=Setoguchi |first2=H. |last3=Roberts |first3=D. L. |last4=Sun |first4=M. |year=2021 |title=Biogeographical patterns and speciation of the genus Pinguicula (Lentibulariaceae) inferred by phylogenetic analyses |journal=PLOS ONE |volume=16 |issue=6 |article-number=e0252581 |doi=10.1371/journal.pone.0252581 |doi-access=free |pmid=34097720 |pmc=8184156 |bibcode=2021PLoSO..1652581S }}</ref>
The great majority of individual ''Pinguicula'' species have a very limited [[Population distribution|distribution]], often restricted to few canyons or mountain cliffs. The two butterwort species with the widest distribution - ''[[Pinguicula alpina|P. alpina]]'' and ''[[Pinguicula vulgaris|P. vulgaris]]'' - are found throughout much of Europe and North America and in some regions in Asia. Other species found in North America include ''[[Pinguicula caerulea|P. caerulea]]'', ''[[Pinguicula ionantha|P. ionantha]]'', ''[[Pinguicula lutea|P. lutea]]'', ''[[Pinguicula macroceras|P. macroceras]]'', ''[[Pinguicula planifolia|P. planifolia]]'', ''[[Pinguicula primuliflora|P. primuliflora]]'', ''[[Pinguicula pumila|P. pumila]]'', and ''[[Pinguicula villosa|P. villosa]]''.{{Citation needed|date=April 2025}}
== Habitat == [[File:Pinguicula macroceras nortensis ne1.JPG|thumb|165px|left|''P. macroceras ssp. nortensis'' growing on a wet rock wall in northern California.]] [[File:Pinguicula leptoceras.jpg|thumb|200px|right|''P. leptoceras'' in alpine grassland in Südtirol, Italy]] In general, butterworts grow in nutrient-poor, alkaline soils. Some species have adapted to other soil types, such as acidic [[peat bog]]s (ex. ''[[Pinguicula vulgaris|P. vulgaris]]'', ''[[Pinguicula calyptrata|P. calyptrata]]'', ''[[Pinguicula lusitanica|P. lusitanica]]''), soils composed of pure [[gypsum]] (''[[Pinguicula gypsicola|P. gypsicola]]'' and other Mexican species), or even vertical rock walls (''[[Pinguicula ramosa|P. ramosa]]'', ''[[Pinguicula vallisneriifolia|P. vallisneriifolia]]'', and most of the Mexican species). A few species are epiphytes (''[[Pinguicula casabitoana|P. casabitoana]]'', ''[[Pinguicula hemiepiphytica|P. hemiepiphytica]]'', ''[[Pinguicula lignicola|P. lignicola]]''). Many of the Mexican species commonly grow on mossy banks, rock, and roadsides in oak-pine forests. ''Pinguicula macroceras ssp. nortensis'' has even been observed growing on hanging dead grasses. ''[[Pinguicula lutea|P. lutea]]'' grows in pine [[flatwoods]].<ref>{{cite journal | vauthors = Keddy PA, Smith L, Campbell DR, Clark M, Montz G | year = 2006 | title = Patterns of herbaceous plant diversity in southeastern Louisiana pine savannas | journal = Applied Vegetation Science | volume = 9 | issue = 1 | pages = 17–26 | doi = 10.1111/j.1654-109X.2006.tb00652.x | bibcode = 2006AppVS...9...17K }}</ref> Other species, such as ''[[Pinguicula vulgaris|P. vulgaris]]'', grow in [[fen]]s. Secondary habitats, such as [[Anthropogenic biome|anthropogenic biomes]], might include steep rock walls along the roads<ref>{{cite web |title=Pinguicula acuminata |url=https://www.pinguicula.org/plants/acuminata/ |website=Pinguicula.org |date=18 January 2026 |access-date=2026-04-19}}</ref> or roadside ditches<ref>{{cite web |title=Pinguicula ionantha (Violet-flowered Butterwort) |url=https://saveplants.org/plant-profile/3460/Pinguicula-ionantha/Violet-flowered-Butterwort/ |website=Center for Plant Conservation |access-date=2026-04-19}}</ref>. Each of these environments is nutrient-poor, allowing butterworts to escape competition from other canopy-forming species, particularly grasses and sedges.<ref>Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. Chapter 5.</ref>
Butterworts need habitats that are almost constantly moist or wet, at least during their carnivorous growth stage. Many Mexican species lose their carnivorous leaves, and sprout succulent leaves, or die back to onion-like "bulbs" to survive the winter drought, at which point they can survive in bone-dry conditions. The moisture they need for growing can be supplied by either a high [[water table|groundwater table]], or by high humidity or high precipitation. Unlike many other carnivorous plants that require sunny locations, many butterworts thrive in part-sun or even shady conditions.
== Conservation status == The environmental threats faced by various ''Pinguicula'' species depend on their location and on how widespread their distribution is. Most endangered are the species which are [[endemic (ecology)|endemic]] to small areas, such as ''[[Pinguicula ramosa|P. ramosa]]'', ''[[Pinguicula casabitoana|P. casabitoana]]'', and ''[[Pinguicula fiorii|P. fiorii]]''. These populations are threatened primarily by [[habitat destruction]]. [[Wetland]] destruction has threatened several US species. Most of these are federally listed as either threatened or endangered, and ''[[Pinguicula ionantha|P. ionantha]]'' is listed on [[CITES]] appendix I, giving it additional protection.{{Citation needed|date=April 2025}}
== Botanical history == [[File:Illustration Pinguicula vulgaris0.jpg|thumb|180px|''Pinguicula vulgaris'', illustration]] The first mention of butterworts in botanical literature is an entry entitled {{Lang|de|Zitroch chrawt oder schmalz chrawt}} ("lard herb") by [[Vitus Auslasser]] in his 1479 work on medicinal herbs entitled ''Macer de viribus Herbarum''.<ref name="auslasser-1479">{{cite book |last1=Auslasser |first1=Vitus |title=Macer de viribus herbarum |date=1479 |publisher=Digitised by Bayerische Staatsbibliothek, München |page=272r |url=https://www.digitale-sammlungen.de/en/view/bsb00092488?page=547 |access-date=6 April 2026}}</ref> The name {{Lang|de|Zittrochkraut}} is still used for butterworts in [[Tyrol (state)|Tirol]], Austria.
In 1583, [[Carolus Clusius|Clusius]] already distinguished between two forms in his ''Historia stirpium rariorum per Pannoniam, Austriam'': a blue-flowered form (''[[Pinguicula vulgaris|P. vulgaris]]'') and a white-flowered form (''[[Pinguicula alpina]]''). [[Carl Linnaeus|Linnaeus]] added ''[[Pinguicula villosa|P. villosa]]'' and ''[[Pinguicula lusitanica|P. lusitanica]]'' when he published his ''[[Species Plantarum]]'' in 1753. The number of known species rose sharply with the exploration of the new continents in the 19th century; by 1844, 32 species were known.
It was only in the late 19th century that the carnivory of this genus began to be studied in detail. In a letter to [[Asa Gray]] dated June 3, 1874, [[Charles Darwin]] mentioned his early observations of the butterwort's digestive process and [[insectivorous]] nature.<ref>{{Cite book|last=Darwin|first=Charles|url=https://books.google.com/books?id=_AK7BwAAQBAJ&q=%22Day+before+Yesterday+I+found+out+that+Pinguicula+digests%22|title=The Correspondence of Charles Darwin: Volume 22, 1874|date=2015|publisher=[[Cambridge University Press]]|isbn=978-1-316-24095-3|page=487|language=en}}</ref> Darwin studied these plants extensively.<ref>{{cite book | author=[[Charles Darwin|Darwin]] C | title=Insectivorous plants | publisher=John Murray | location=London | year=1875 | url=http://pages.britishlibrary.net/charles.darwin3/insectivorous/insect01.htm | isbn=1-4102-0174-0 | archive-url=https://web.archive.org/web/20060923021622/http://pages.britishlibrary.net/charles.darwin3/insectivorous/insect01.htm | archive-date=2006-09-23 }}</ref> [[Siegfried Jost Casper|S. J. Casper's]] large 1966 monograph of the genus<ref name="casper1966">{{cite book | author=Casper SJ | title=''Monographie der Gattung ''Pinguicula'' L.'' (Heft 127/128, Vol 31) | publisher=[[Bibliotheca Botanica]] | location=Stuttgart| year=1966 }}</ref> included 46 species, a number which has almost doubled since then. Many exciting discoveries have been made in recent years, especially in Mexico. Another important development in the history of butterworts is the formation of the [[International Pinguicula Study Group]], an organization dedicated to furthering the knowledge of this genus and promoting its popularity in cultivation, in the 1990s.
== Uses == Butterworts are widely cultivated by carnivorous plant enthusiasts. The temperate species and many of the Mexican butterworts are relatively easy to grow and have therefore gained relative popularity. Two of the most widely grown plants are the hybrid [[cultivar]]s ''Pinguicula'' × 'Sethos' and ''Pinguicula'' × 'Weser'. Both are crosses of ''[[Pinguicula ehlersiae]]'' and ''[[Pinguicula moranensis]]'', and are employed by commercial [[orchid]] nurseries to combat pests.{{citation needed|date=June 2019}}
Butterworts also produce a strong bactericide which prevents insects from rotting while they are being digested. According to [[Carl Linnaeus|Linnaeus]], this property has long been known by northern Europeans, who applied butterwort leaves to the [[Ulcer (dermatology)|sores]] of cattle to promote healing.<ref>{{cite book | author=D'Amato P | title=The Savage Garden: Cultivating Carnivorous Plants | title-link=The Savage Garden: Cultivating Carnivorous Plants | publisher=Ten Speed Press | year=1988 | isbn= 0-89815-915-6 }}</ref> Additionally, butterwort leaves were used to [[curdle]] milk and form a buttermilk-like [[fermented milk product]] called {{Lang|sv|[[filmjölk]]}} (Sweden) and {{Lang|no|tjukkmjølk}} (Norway).<ref>{{cite journal |doi=10.4000/aof.211 |doi-access=free |title=From local food to terroir product ? - Some views about Tjukkmjølk, the traditional thick sour milk from Røros, Norway |year=2005 |last1=Amilien |first1=Virginie |last2=Torjusen |first2=Hanne |last3=Vittersø |first3=Gunnar |journal=Anthropology of Food |volume=4 |issue=4 }}</ref>
== Classification == {{see also|List of Pinguicula species}}
''Pinguicula'' belong to the bladderwort family ([[Lentibulariaceae]]), along with ''[[Utricularia]]'' and ''[[Genlisea]]''. [[Siegfried Jost Casper]] [[systematics|systematically]] divided them into three [[subgenus|subgenera]] with 15 [[Section (botany)|sections]].<ref name="casper1966" />
A detailed study of the phylogenetics of butterworts by Cieslak ''et al.'' (2005)<ref name="cieslak2005" /> found that all of the currently accepted [[subgenus|subgenera]] and many of the [[section (biology)|sections]] were [[polyphyletic]]. The diagram below gives a more accurate representation of the correct [[cladogram]]. Polyphyletic sections are marked with an '''<nowiki>*</nowiki>'''.
┌────Clade I (Sections Temnoceras '''<nowiki>*</nowiki>''', Orcheosanthus '''<nowiki>*</nowiki>''', Longitubus, │ Heterophyllum '''<nowiki>*</nowiki>''', Agnata '''<nowiki>*</nowiki>''', Isoloba '''<nowiki>*</nowiki>''', Crassifolia) │ ┌───┤ │ │ │ │ ┌──────┤ └────Clade II (Section Micranthus '''<nowiki>*</nowiki>''' = ''P. alpina'') │ │ │ │ ┌───┤ └────────Clade III (Sections Micranthus '''<nowiki>*</nowiki>''', Nana) │ │ │ │ ───┤ └───────────────Clade IV (Section Pinguicula) │ │ └───────────────────Clade V (Sections Isoloba '''<nowiki>*</nowiki>''', Ampullipalatum, Cardiophyllum)
== References == <!--See http://en.wikipedia.org/wiki/Wikipedia:Footnotes for an explanation of how to generate footnotes using the <ref(erences/)> tags--> <references/>
==Further reading== * {{cite book |vauthors=Barthlott W, Porembski S, Seine R, Theisen I | title=Karnivoren | publisher=Verlag Eugen Ulmer | location=Stuttgart| year=2004 | isbn= 3-8001-4144-2 }} * {{cite journal |vauthors=Müller K, Borsch T, Legendre L, Porembski S, Theisen I, Barthlott W | title=Evolution of carnivory in Lamiales | journal=Plant Biology | volume=6 | issue=4| year=2004| pages=1–14 | pmid=15248131 | doi=10.1055/s-2004-817909| bibcode=2004PlBio...6..477M }} * Keddy, P.A. (2010). Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. * Givnish, T. J. (1988). Ecology and evolution of carnivorous plants. In Plant–Animal Interactions, ed. W. B. Abrahamson, pp. 243–90. New York: McGraw-Hill.
==External links== * {{Commons-inline}} * {{Wikispecies-inline|Pinguicula}} * [http://www.pinguicula.org/ An exhaustive website on the genus ''Pinguicula''] * Schlauer, J. [http://www.omnisterra.com/bot/cp_home.cgi Carnivorous Plant Database] {{Webarchive|url=https://web.archive.org/web/20160918161537/http://www.omnisterra.com/bot/cp_home.cgi |date=2016-09-18 }}, version 15 November 16: 25. * [http://rbg-web2.rbge.org.uk/cgi-bin/nph-readbtree.pl/feout?FAMILY_XREF=&GENUS_XREF=Pinguicula&SPECIES_XREF=&TAXON_NAME_XREF=&RANK=species Flora Europaea: ''Pinguicula'' species list] * [http://www.botany.org/Carnivorous_Plants/Pinguicula.php Botanical Society of America, ''Pinguicula'' - the Butterworts] {{Webarchive|url=https://web.archive.org/web/20130103153551/http://www.botany.org/Carnivorous_Plants/Pinguicula.php |date=2013-01-03 }}
{{CarnivorousPlants}} {{Taxonbar|from=Q161663}} {{Authority control}}
[[Category:Pinguicula| ]] [[Category:Carnivorous plants of Africa]] [[Category:Carnivorous plants of Asia]] [[Category:Carnivorous plants of Central America]] [[Category:Carnivorous plants of Europe]] [[Category:Carnivorous plants of North America]] [[Category:Carnivorous plants of South America]] [[Category:Lamiales genera]]