Name: Ipomoea pandurata (L.) G Mey.
Family: Convolvulaceae, the bindweed or morning glory family
Common Names: Man of the earth, wild sweet potato, big-root morning-glory, man-root, wild-potato, wild-sweet-potato-vine, Indian potato (2,3,9,15).
Etymology: The genus name Ipomoea is from the Greek ips, which means “a worm,” and homoios which, means “resembling,” referring to the wormlike twining habit. The epithet pandurata means “fiddle-like” most likely referring to the leaf shape (20).
Botanical synonyms: Convolvulus panduratus L. (15).
Quick Notable Features
¬ Large underground storage organ
¬ Simple, polymorphic leaves: cordate or fiddle-shaped on long petioles
¬ Large white flowers with lavender to purple centers
¬ Hairy seeds
Plant Height: Easily up to 3m in length, but occasionally growing to 4.6m (1,4).
Subspecies/varieties recognized (5):
I. pandurata var. candicans Choisy
I. pandurata var. rubescens Choisy
I. pandurata var. hastata Chapm
Habitat Preference: Ipomoea pandurata is found in moist to slightly dry, disturbed habitats, such as slopes, agricultural fields, roadsides, and railway right-of-ways (7,8).
Geographic Distribution in Michigan: I. pandurata is found in Berrien, Kalamazoo, Kent, St. Clair, and Monroe counties (8).
Known Elevational Distribution: The species was collected at 1340m above sea level in Tejupilco, Mexico (9).
Complete Geographic Distribution: Native to the United States, I. pandurata is found in most eastern states (AL, AR, CT, DC, DE, FL, GA, IA, IL, IN, KS, KY, LA, MA, MD, MI, MO, MS, NC, NE, NJ, NY, OH, OK, PA, SC, TN, TX, VA, WV), Canada (ON), Mexico, and Japan (2,9).
Vegetative Plant Description: Ipomoea pandurata is a perennial twinning or trailing herb with smooth to slightly pubescent, occasionally purplish stems. It forms a very large underground storage organ (up to 11kg). Sources vary in stating the morphological organ that is represented: some suggest it is a tuber (3,4,8) and some suggest it is a storage root (1,4,21). We believe it is a modified stem, but the variance in the sources is an interesting phenomenon. Each storage organ can produce 4-8 shoots. The entire leaves are simple, alternate, heart-shaped to ovate, or pandurate (contracted in the center or fiddle-shaped), 3.5-8cm long and 2.5-8cm broad, with 1-8cm long petioles. The blades are short-pubescent to glabrous on both surfaces (most commonly below), and about as wide as long (3-10cm) (1,4,14,16,17,21).
Flower Description: The cymose inflorescence is composed of 1-7 perfect actinomorphic flowers. The pedicel is longer than the petiole, stout, and contains extrafloral nectaries near the base of the flower. The calyx (1.3-1.9cm long) is light green, generally glabrous, imbricate, and 5-lobed, with long narrow ridges. The sepals (1.2-1.5cm long) are narrowly ovate to elliptic, the inner often longer than the outer. I. pandurata has a funnelform corolla that is wider (7-10cm) than long (4.5-8cm), white with violet to red-purple in the tube. The pubescent stamens are 2-3cm long, not exserted, with anthers that are 5-7mm long. The two-locular, glabrous ovary is superior, the style topped with a 2-lobed, globular stigma, surrounded by a yellow nectary, 1.5-2.3mm broad. The ovary shape is ovoid, and each ovary contains 4 ovules. Stucky & Beckmann (1982) observed that anthesis usually occurs between 2 and 4am (1,3,6,12,14,16,17).
Flowering Time: The species flowers from late May-September (1,17).
Pollinator: The flowers are visited and pollinated by insects, including long-tongued bees, Ptilothrix bombiformis, Bombus pennsylvanicus, Melissodes ssp., and Melitoma taurea (1,3,11). Ipomoea ssp. flowers are also known to be bat pollinated in the southwestern U.S. (10). Bat pollination may be in better agreement with anthesis time than bees.
Fruit Type and Description: The fruit is a glabrous, ovoid, 2-celled, dehiscent capsule, 1-1.5cm long, containing 2-4 seeds (3,13,14,17).
Seed Description: The oblong seeds are dull brown to red in color, and densely covered with tiny, brownish hairs. Wooly trichomes are present along the angles. Seed set has been reported to be rare, due to pollen tube failure as well as sterility mechanisms in the ovary. Highest germination success was coincident with seed scarification (sulfuric acid or mechanical), at which point the cotyledons emerge from the ground, (e.g., epigeal germination). Axillary buds are reported to be present well below the cotyledon, allowing for resprouting if the top of the seedling is removed by herbivory (1,4,13).
Dispersal Syndrome: At maturity, the capsules open to expose the wind dispersed seeds, likely facilitated by the hairs surrounding the seeds. The species can also be propagated by root cuttings (1).
Distinguished by: Ipomoea pandurata can be distinguished from other species of Ipomoea in Michigan using the following features. Ipomoea x multifida has very deeply lobed leaves and a red corolla that is salverform, not funnelform, with exserted stamens. I. hederacea has pubescent stems, pubescent acute sepals, and a 3-lobed stigma, while I. pandurata has nearly glabrous stems and rounded, essentially hairless sepals (with the exception of occasional scarce apical pubescence). In addition, I. hederacea leaves can be 3-lobed, the corolla is smaller (3-4.5cm long) and blue – pink – purple with a white tube. I. pandurata can be distinguished from the annual I. purpurea by the strongly reflexed hairs on the pedicels, stems, and sepals, the 3-lobed stigma, and the varied corolla pigmentation, most commonly purple-pink or white, but with no purplish tube. Calystegia silvatica has similar flowers, but the leaves of C. silvatica have a wider sinus, sometimes square, and the leaf lobes may bear large teeth. Flowering specimens of the two are differentiated by the all-white corolla and the subtending bracts enclosing the calyx in Calystegia silvatica, neither present in I. pandurata. Convolvulus arvensis has narrow deltoid to sagittate leaves, generally smaller (only 4cm x 3cm). The flowers have a pink corolla or a white corolla with pink radial stripes, and filiform stigmas. Dioscorea villosa has similar cordate leaves, however, leaves at the base of the plant are whorled, and the upper leaves alternate, all with arcuate, apically converging veins. In I. pandurata, all leaves are alternate and veins are not arcuate. Additionally, D. villosa is dioecious (pistillate and staminate flowers in different plants), bears spike or paniculate inflorescences and much smaller flowers. Aristolochia macrophylla has similar heart-shaped, alternate leaves, however it is a woody vine, not herbaceous as I. pandurata, and the leaves are usually over 8cm broad. A. macrophylla flowers are zygomorphic and have no corolla (6,8,14,16).
Other members of the family in Michigan (number species): Calystegia (5), Convolvulus (1), Cuscuta (9), and Ipomoea (4) (source 8).
Ethnobotanical Uses: The roots were used by Native Americans to prepare a poultice to treat rheumatism, an infusion for cholera or kidney disease, or a decoction taken for abdominal pains, coughs, and early stages of tuberculosis. The plant was powdered and used to make an infusion for headaches and upset stomachs. To keep pests away from sweet potatoes, Native Americans prepared an infusion of the whole I. pandurata plant and submerged the potatoes in it. The cooked roots were also used as food source (19).
Phylogenetic Information: The Convolvulaceae is a member of the order Solanales. Solanales forms a monophyletic group with Lamiales and belongs to the Asterid I clade. Within Convolvulaceae there are two groups: Humbertioideae, the rare large trees, and Convolvuloideae, comprising both woody and herbaceous vines. Edible and ornamental members of this family are found worldwide, with the exception of polar regions, and the deserts of Patagonia, Sahara, and Taklimaka (18).
Interesting Quotation or Other Interesting Factoid not inserted above: The extrafloral nectaries attract hymenopterans (ants and wasps), which ferociously protect the plant from herbivorous insects (12). The taproot is capable of growing longer than 2 meters and over 1 meter in diameter, weighing up to 30kg (21). If ingested, the seeds of several Ipomoea species are poisonous to humans and livestock (21). Symptoms include: hallucinations, dilated pupils, nausea, vomiting, diarrhea, drowsiness, numbness of extremities, and muscle tightness upon ingestion (22). The species is listed as threatened in Michigan, and endangered in New York (2). The cultivated sweet potato, Ipomoea batatas, is a different species in the same genus as the wild sweet potato (23).
“Was it worth while to paint so fair
Thy every leaf-to vein with faultless art
Each petal, taking the book light and air
Of summer so to heart?…
Thy silence answers: “Life was mine!
And I, who pass without regret or grief,
Have cared the more to make my moment fine,
Because is was so brief.”-The Morning-Glory by Florence Earle Coates (1850-1927)
Literature and websites used:
- Stucky, J.M. & R.L. Beckmann 1982. Pollination biology, self-incompatibility, and sterility in Ipomoea pandurata (L.) G.F.W. Meyer (Convolvulaceae). American Journal of Botany 69(6): 1022-1031.
- USDA, NRCS. 2008. The PLANTS Database, Version 3.1, National Plant Data Center, Baton Rouge, LA 70874-4490 USA. http://plants.usda.gov/. (26 April 2012).
- Hilty, J. 2004-2012. Wildflowers of Illinois in Savannas & Thickets. http://www.illinoiswildflowers.info/savanna/plants/ws_potato.htm.
- Hagood, S. Virginia Tech Weed Identification Guide, Virginia Cooperative Extension. http://www.ppws.vt.edu/scott/weed_id/ipopn.htm (05/02/2012).
- The International Plant Names Index (2008). Published on the Internet: http://www.ipni.org [Accessed 20 October 2010].
- Gleason, H. A. 1963. Illustrated Flora of the Northeastern United States and Adjacent Canada, Volume 3. New York, NY: Hafner Publishing Company, Inc.
- Weakley, A. 2010. Flora of the Southern and Mid-Atlantic States, Working Draft of 8 March 2010. Published online at http://www.herbarium.unc.edu/flora.htm.
- Michigan Flora Online. A.A. Reznicek, E.G. Voss, & B.S. Walters February 2011. University of Michigan. Web. April 26, 2012. http://michiganflora.net/species.aspx?id=860.
- Biodiversity occurrence data (Accessed through GBIF Data Portal, data.gbif.org, 04/25/2012).
- Hevly, R.H. 1979. Dietary habits of two nectar and pollen feeding bats in Southern Arizona and Northern Mexico. Journal of the Arizona-Nevada Academy of Science 14(1): 13-18.
- Mead, M.D., S.D. Sipes, & A.M. Anterola 2008. A preliminary analysis of the floral scents of Ipomoea pandurata (Convolvulaceae) and Hibiscus moscheutos (Malvaceae): implications for the role of floral odor in host-plant selection by specialist bees. 93rd ESA Annual Meeting (August 3 — August 8, 2008)
- Beckman, R.L. & J.M. Stucky 1981. Extrafloral nectaries and plant guarding in Ipomoea pandurata (L.) G. F. W. Mey. (Convolvulaceae). American Journal of Botany 68(1): 72-79.
- Horak, M.J. and L.M. Wax 1991. Germination and seedling development of Bigroot Morningglory (Ipomoea pandurata). Weed Science 39: 390-396.
- Radford, A.E., H.E. Ahles, & C.R. Bell 1968. Manual of the Vascular Flora of the Carolinas. Chapel Hill, NC: The University of North Carolina Press.
- Tropicos.org. Missouri Botanical Garden. Accessed 26 Apr 2012 http://www.tropicos.org/Name/8500734
- Fernald, M.L. 1950. Gray’s Manual of Botany, 8th ed. New York: American Book Company.
- McGregor R.L. 1986. Flora of the Great Plains. Lawrence, KS: The University Press of Kansas.
- Stevens, P.F. Angiosperm Phylogeny Website. Version 7, May 2006. http://www.mobot.org/MOBOT/research/APweb
- Native American Ethnobotany Database 2003. University of Michigan Dearborn. http://herb.umd.umich.edu/herb/search.pl?searchstring=Ipomoea%20pandurata&searchlimit=100 (05/21/2012).
- Stearn, W.T. 1992. Stearn’s Dictionary of Plant Names for Gardeners. London: Cassel Publishers Limited.
- Ohio Perennial and Biennial Weed Guide. Bigroot Morningglory. http://www.oardc.ohio-state.edu/weedguide/singlerecord.asp?id=640 (05/21/2012).
- Evergreen Native Plant Database 2000-2011. Plant Detail: Ipomoea pandurata. http://nativeplants.evergreen.ca/search/view-plant.php?ID=05333 (05/21/2012).
- Wolford, R. & D. Banks. Watch your garden grow: sweet potato. University of Illinois Extension. http://urbanext.illinois.edu/veggies/sweetpotato.cfm
Image Credits (all used with permission):
1) Image of whole plant courtesy of Steven J. Baskauf
2) Image of root courtesy of Ohio State Weed Lab Archive, The Ohio State University, Bugwood.org http://www.forestryimages.org/browse/detail.cfm?imgnum=1552299
3) Image of flower courtesy of Christopher Bailey
4) Image of seeds courtesy of Steve Hurst
5) Species distribution map, derived from the Michigan Flora Online.
Primary Authors: Ashley Erwin with revisions and editing by Cristine V. Santanna, Jenna Dorey, John Bradtke, and Robyn J. Burnham.
© Robyn J. Burnham, University of Michigan
For additional information on Michigan Plant Diversity species accounts, please contact Robyn J. Burnham via email: rburnham“at”umich.edu