Pinguicula vulgaris - Michigan Natural Features Inventory - Michigan ...

utterwort, Page 1 

Pinguicula vulgaris L. butterwort 

Photo by Susan R. Crispin 

Status: State special concern 

Global and state rank: G5/S3 

Other common names: common butterwort, bogviolet, 

violet butterwort 

Family: Lentibulariaceae (bladderwort family) 

Range: Butterwort is a circumpolar species ranging 

around the world in temperate and boreal regions. It is 

of widespread occurrence from Europe through Siberia. 

Elsewhere this species occurs in the Arctic from Alaska 

to Canada and East Greenland, extending southward 

in North America to northeast Minnesota, northwest 

Wisconsin, and through the Lake Superior region east 

to New York and New England. It is considered rare 

in Alberta, Maine, Minnesota, New Brunswick, New 

Hampshire, New York, Nova Scotia, Saskatchewan, 

Vermont, and Wisconsin (NatureServe 2006). 

State distribution: Michigan localities for P. vulgaris 

are widely distributed, occurring from Isle Royale 

through the Upper Peninsula to the tip of the Lower 

Peninsula. It is known from just over 70 sites, most of 

which (50+ localities) occur in Keweenaw, Mackinac, 

and Alger counties, with four or fewer sites known 

for Delta, Houghton, Marquette, Alpena, Charlevoix, 

Chippewa, Emmet, and Presque Isle counties. 

Michigan Natural Features Inventory 

P.O. Box 30444 - Lansing, MI 48909-7944 

Phone: 517-373-1552 

Jan 

Feb 

Mar 

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Best Survey Period 

May 

Jun 

Jul 

State Distribution 

Aug 

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Dec 

Recognition: Pinguicula vulgaris is a small, 

herbaceous, insectivorous perennial with rosettes of 3-6 

distinctly yellowish-green leaves. The blunt, oblongovate 

to elliptic leaves, which narrow to the base, range 

to ca. 8 cm in length, curling slightly inward along 

their upper margins. The upper leaf surface is covered 

with numerous enzyme-secreting glands that aid in 

the breakdown and digestion of small insects, and give 

the leaves a sticky-greasy feel when touched. This 

slimy, watery surface also serves to attract and capture 

insect prey. The spurred purple flowers are solitary 

on 1.5-12 cm long, leafless peduncles (stalks) and 

have a white spot at the mouth. In addition to a well 

developed basal spur, the flowers have a 3-lobed upper 

lip and 2-lobed lower lip, thus superficially resembling a 

violet. A single rosette may have produce up to three or 

more flowering stalks. The fruit is a small capsule with 

tiny seeds that lack endosperm. 

Best survey time/phenology: Butterwort is best sought 

in spring when in flower, from about early June to 

early July. However, the distinct bright yellowish-green 

basal rosettes can be easily recognized throughout the 

growing season, from approximately late May through 

September. 

FQI Coefficient and Wetland Category: 10, OBL


Habitat: Pinguicula vulgaris is a well-known 

calciphile (favoring alkaline or lime-rich habitats) and 

as with most insectivorous plants, prefers wet substrates. 

It is found in moist alkaline rock crevices and outcrops; 

rocky or gravelly shores, sandy, interdunal shoreline 

flats; marshy soils near bogs, wet alvars, and the marly, 

calcareous soils of coastal and northern fens. It also 

occurs in Lake Superior coastal areas where it inhabits 

volcanic bedrock lakeshore areas, favoring basalts and 

conglomerate bedrock types. Most Michigan locations 

are along Great Lakes shores, particularly on rocky, 

wet beaches and nearshore wetlands and interdunal 

areas. Primula mistassinica (birds-eye primrose) is a 

common associate as are numerous other herbs such as 

Drosera rotundifolia (round-leaved sundew), D. linearis 

(linear-leaved sundew), Sarracenia purpurea (pitcherplant), 

Utricularia intermedia (flat-leaved bladderwort), 

U. cornuta (horned bladderwort), Castilleja coccinea 

(Indian paintbrush), Parnassia glauca grass-of- 

Parnassus), Tofieldia glutinosa (false asphodel), and 

Gentianopsis procera (small fringed gentian). The 

rare Solidago houghtonii (Houghton’s goldenrod) is 

an expected associate in the Straits region, as might be 

Empetrum nigrum (black crowberry) and other rarities 

such as the similarly boreal Erigeron hyssopifolius 

(hyssop-leaved fleabane) and Carex scirpoidea (bulrush 

sedge). These associates are similar to those found with 

butterwort in shoreline limestone pavement or wet alvar 

sites. 

In bedrock shoreline communities in the more 

northern portion of its Michigan range, butterwort 

occurs on alkaline basalts, volcanic conglomerates, 

and occasionally wet sandstones, where associates 

include such species as Campanula rotundifolia 

(harebell), Deschampsia cespitosa (hair grass), 

Festuca saximontana (fescue), Artemisia campestris 

(wormwood), Carex viridula (sedge), and Solidago 

simplex (Gillman’s goldenrod). 

Biology: Pinguicula vulgaris is an insectivorous, 

perennial herb that secretes mucilaginous fluids and 

digestive enzymes through two types of leaf glands. 

Small insects first adhere to the mucilaginous fluids 

secreted by the stalked ‘sticky’ glands. Their struggling 

movements, which stimulate increased production of 

the mucilaginous fluids, then cause the secretion of 

enzyme-containing fluids from the ‘sessile’ glands. It 

is the latter secretion that is primarily responsible for 

insect digestion and nutrient absorption by the plant. 



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Upon stimulation, the leaves also roll inward from their 

margins; this is thought to minimize the loss of prey and 

also aid in enzymatic degradation by increasing the leaf 

surface area in contact with the prey. This in-rolling may 

also reduce the loss of enzymes and nutrients through 

seepage or by preventing exposure to rainfall. 

Flowering plants can be found in late May through 

June and into early July, followed by the formation of 

a capsule containing several seeds, typically from early 

July through August. During winter, butterwort persists 

as a winter resting bud known as a hibernaculum 

that begins to form in the center of the rosette by late 

summer. This bud is entirely without roots and therefore 

may be dispersed by water movement, wind, or 

possibly animal activity. The small scale-leaves of the 

hibernaculum contain starches that nurture the enclosed 

seedling during spring emergence when new leaves and 

roots are forming. 

Biologists have long been interested in carnivorous 

plants, particularly with regard to the topics of 

resource allocation, reproduction, plant demography 

(the structure and dynamics of populations), and the 

evolution of carnivory as an adaptation to low nutrient 

availability. Owing to the extensive nature of this 

literature, which cannot be adequately summarized 

here, the reader is referred to the following references 

for further information on these topics: Méndez and 

Karlsson (2005), Méndez and Karlsson (2004), Eckstein 

and Karlsson (2001), Worley and Harder (1999), Thorén 

and Karlsson (1998), Thorén et al. (1996), Lesica and 

Steele (1996), Worley and Harder (1996), Svensson 

et al. (1993), Kull and Zobel (1991), Karlsson et al. 

(1990), Karlsson 1988), Karlsson and Carlsson (1984), 

and Aldenius et al. (1983). 

Conservation/management: Several large butterwort 

populations are protected on public lands, including 

several sites within Isle Royale National Park, and also 

via a number of private nature preserves, including 

large exemplary areas managed by the Michigan Nature 

Conservancy in the Straits region. Habitat loss through 

shoreline development and recreation is the most 

critical threat to butterwort populations, and as for many 

coastal areas, the prevalence and widespread use of 

off-road-vehicles (ORVs) remains a constant and ever 

present threat to sites. Conservation strategies should 

focus on the identification and preservation of shoreline 

ecosystems that encompass known and potential

habitat. Equally important is the education of private 

landowners as well as federal, state, and local land 

managers to provide guidance on how to identify and 

steward important coastal systems and their associated 

rare species. 

Comments: The word Pinguicula is derived from the 

Latin word pinguis, meaning ‘fat’, and refers to the 

leaves being ‘greasy’ or ‘buttery’ to the touch. It is 

reported that the leaves were once used by farmers to 

coagulate milk. 

Research needs: The principal need at present, given 

the extensive research that has been conducted to 

date, is perhaps the identification of viable colonies 

and conducting monitoring to determine population 

dynamics, trends, changes in status, and the presence of 

natural and artificial threats. 

Related abstracts: Coastal fen, northern fen, interdunal 

wetland, sand and gravel shore, limestone bedrock 

lakeshore, limestone cobble shore, volcanic bedrock 

lakeshore, cherrystone drop, Eastern massasauga, Hine’s 

emerald, incurvate emerald, crested vertigo, six-whorl 

vertigo, tapered vertigo, alpine bluegrass, calypso, 

English sundew, Franklin’s Phacelia, Hill’s thistle, 

Houghton’s goldenrod, prairie Indian plantain, ram’s 

head orchid, Richardson’s sedge, rock whitlow-grass, 

and numerous additional animal and plant species. 

Selected references: 

Aldenius, J., B. Carlsson, and S. Karlsson. 1983. 

Effects of insect trapping on growth and nutrient 

content of Pinguicula vulgaris L. in relation to the 

nutrient content of the substrate. New Phytologist 

93: 53-59. 

Eckstein, R.L. and P.S. Karlsson. 2001. The effect of 

reproduction on nitrogen use-efficiency of three 

species of the carnivorous genus Pinguicula. J. 

Ecol. 89: 798-806. 

Heide, Fr. 1912. Medd. Om Gronland. 36:441-47. 

Kull, K. and M. Zobel. 1991. High species richness in 

an Estonian wooded meadow. J. Veg. Sci. 2: 715- 

718. 

Karlsson, P.S., B.M. Svensson, B.Ǻ, and K.O. Nordell. 

1990. Resource investment in reproduction and its 



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butterwort, Page 3 

consequences in three Pinguicula species. Oikos 

59: 393-398. 

Karlsson, P.S. 1988. Seasonal patterns of nitrogen, 

phosphorous and potassium utilization by three 

Pinguicula species. Functional Ecology 2: 203-209. 

Karlsson, P.S. and B. Carlsson. 1984. Why does 

Pinguicula vulgaris L. trap insects? New 

Phytologist. 97: 25-30. 

Lesica, P. and B.M. Steele. 1996. A method for 

monitoring long-term population trends: an 

example using rare arctic-alpine plants. Ecological 

Applications 6: 879-887. 

Lloyd, Francis E. 1942. The Carnivorous Plants. 

Chronica Botanica, Waltham. 

Méndez, M. and P.S. Karlsson. 2005. Nutrient 

stoichiometry in Pinguicula vulgaris: nutrient 

availability, plant size, and reproductive status. 

Ecology 86: 982-991. 

Méndez, M. and P.S. Karlsson. 2004. Betweenpopulation 

variation in size-dependent reproduction 

and reproductive allocation in Pinguicula vulgaris 

(Lentibulariaceae) and its environmental correlates. 

Oikos 104: 59-70. 

Méndez, M., D.G. Jones, and Y. Manetas. 1999. 

Enhanced UV-B radiation under field conditions 

increases anthocyanin and reduces the risk of 

photoinhibition but does not affect growth in 

the carnivorous plant Pinguicula vulgaris. New 

Phytologist 144: 275-282. 

NatureServe. 2006. NatureServe Explorer: an online 

encyclopedia of life [web application]. Version 

6.1. NatureServe, Arlington, Virginia. Available 

http://www.natureserve.org/explorer. (Accessed: 

December 15, 2006). 

Slack, A. 1979. The Carnivorous Plants. MIT Press, 

Cambridge, MA 

Thorén, L.M. and P.S. Karlsson. 1998. Effects of 

supplementary feeding on growth and reproduction 

of three carnivorous plant species in a subarctic 

environment. Journal of Ecology 86: 501-510.


Thorén, L.M., P.S. Karlsson, and J. Tuomi. 1996. 

Somatic cost of reproduction in three carnivorous 

Pinguicula species. Oikos 76: 427-434. 

Svensson, B.M., B.Ǻ. Carlsson, P.S. Karlsson, and 

K.O. Nordell. 1993. Comparative long-term 

demography of three species of Pinguicula. J. Ecol. 

81: 635-645. 

Voss, E.G. 1996. Michigan Flora. Part III. Dicots 

(Pyrolaceae-Compositae). Bull. Cranbrook Inst. 

Sci. 61 and Univ. of Michigan Herbarium. xix + 

622 pp. 

Worley, A.C. and L.D. Harder. 1999. Consequences 

of preformation for dynamic resource allocation 

by a carnivorous herb, Pinguicula vulgaris 

(Lentibulariaceae). Amer. Jour. Bot. 86: 1136- 

1145. 

Worley, A.C. and L.D. Harder. 1996. Size-dependent 

resource allocation and costs of reproduction in 

Pinguicula vulgaris (Lentibulariaceae). J. Ecol. 84: 

195-206. 

Abstract citation: 

Penskar, M.R. and J.A. Hansen. 2009. Special Plant 

Abstract for Pinguicula vulgaris (butterwort). 

Michigan Natural Features Inventory, Lansing, MI. 

4 pp. 

Copyright 2009 Michigan State University Board of Trustees. 

MSU Extension is an affirmative-action, equal-opportunity 

organization. 

Funding for abstract provided by the Michigan Department of 

Transportion. 



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