Name: Cuscuta pentagona Engelmann
Family: Convolvulaceae, the Morning Glory Family
Common Names: Five-cornered dodder, five angled dodder, field dodder, western field dodder. Also simply called dodder or love-vine, names given generally to the genus Cuscuta (2,4,5,6).
Etymology: With Arabic origins, Kushkut, means dodder plant or parasitic plant; in New Latin, Cuscuta directly translates as dodder. The species name pentagona means “5-angled” (3,7,16).
Botanical synonyms (1):
Cuscuta arvensis var. pentagona (Engelm.) Engelm.
Cuscuta arvensis Beyr. ex Engelm.
Cuscuta campestris Yunck.
Grammica campestris (Yunck.) Hadač & Chrtek Grammica pentagona (Engelm.) W.A. Weber
Cuscuta obtusiflora Kunth (the accepted name under TROPICOS system)
Quick Notable Features (3,4,19):
¬ Annual, pale orange, slender stems
¬ Loose cymes bearing up to 20 flowers
¬ Nearly sessile 5-merous flowers bearing angled sepals
¬ Infrastaminal scales fringed and nearly as long as the corolla tube
Plant Height: C. pentagona stems have been measured as longer than 12m (17).
Subspecies/varieties recognized (1):
C. pentagona var. calycina Engelm.
C. pentagona var. glabrior (Engelm.) Gandhi, R.D. Thomas & S.L. Hatch
C. pentagona var. microcalyx Engelm.
C. pentagona var. pentagona
C. pentagona var. pubescens (Engelm.) Yunck.
C. pentagona var. subulata Yunck.
C. pentagona var. verrucosa (Engelm.) Yunck.
Most Likely Confused with: Cuscuta indecora, C. cephalanthi, C. coryli, C. glomerata, C. gronovii, and C. polygonorum (2).
Habitat Preference: In Michigan, C. pentagona parasitizes species of Rubus (raspberries and blackberries), Ceanothus, Euphorbia corollata, Impatiens, Chamaedaphne, Bidens, grasses, clover, alfalfa, and sugar beets. It prefers forests and fields with sandy, dry soils. Along with a few other species of Cuscuta, C. pentagona must parasitize dicotyledonous plants to survive, although it may twine around monocots (2,19).
Geographic Distribution in Michigan: C. pentagona is found in Kalamazoo, Wayne, Calhoun, Macomb, Oakland, and Washtenaw counties (2).
Known Elevational Distribution: The species was collected at an altitude of 1798m in Plumas, CA (1).
Complete Geographic Distribution: Native to North America, the species is found in almost every state in the United States except Wyoming, Vermont, Maine, and the Virgin Islands. The species is considered introduced in Hawaii. In Canada, it is found in BC, MB, NB, NF, NS, ON, QC, SK. C. pentagona is also found in Argentina, Belize, Madagascar, Mexico, Suriname, Tanzania, Uganda, Venezuela, China, South Africa, Brazil, Bahamas, Cuba, Jamaica, Colombia, and Ecuador (1,5).
Parasitism: Parasitism is a type of symbiotic relationship in which one organism obtains nutrients directly from a host organism. This has a detrimental effect on the host, but benefits the parasite. Although parasitic plants are commonly known to lack chlorophyll, some species have green organs, making them partially photoautotrophic. The physical link between the parasite and the host is called a “haustorium,” and often occurs through xylem-to-xylem attachment. The host can vary, ranging from the mycorrihizae of trees, to grasses and hardwood trees. The parasite often maintains open or partially open stomata, allowing transpiration to aid in extracting nutrients from the host (14).
Vegetative Plant Description: When Cuscuta species germinate, they develop a short anchorage root, while a stem forms and nutates (rotates) in search of a host. When an attachment with a host has been created, the anchorage root dies (15). Additional means of finding a host have been suggested in literature, such as positive photoautotrophy or growth toward a source of moisture or specific chemicals (10). The stems of C. pentagona are very thin (0.35-0.8mm in diameter), cylindrical, smooth, pale yellow-orange, and may bear glands; they coil around the host plant in a dextral orientation. Leaves are absent, instead there are very small, alternate scales (3,4,8,9,17,18,19).
Flower Description: The inflorescences are loose cyme heads (glomerules) bearing short pedicelled (ca. 1mm long), glandular whitish flowers (1.5-3mm long), 5-20 per glomerule. The gamosepalous calyx is 5-parted; the lobes short, broad, and apically rounded. The calyx (ca. 1.5mm long) is about the same length as the corolla tube, with lobes overlapping at the sinuses. The corolla is 5-lobed; the inflexed lobes are spreading, narrower than the sepals, lanceolate, apically acute, nearly as long as the tube, smooth, and persistent at the base of the fruit. The infrastaminal scales are oblong, fringed, and from half to as-long-as the corolla tube. Five exserted epipetalous stamens are subtended by the scales. The superior ovary is depressed-globose, 2-locular, with 2 styles (ca. 1.5mm long) shorter than the ovary or equal, with capitate stigmas (2,3,4,9,18,19,20).
Flowering Time: May until the first frost (18,20).
Pollinator: C. pentagona is autogamous (capable of self-pollination) and cleistogamous (flowers remain closed to avoid pollination, but seeds develop regardless) (13,19). Yuncker observed visits by wasps and other species of the order Hymenoptera to unspecified members of the genus Cuscuta (11).
Fruit Type and Description: The fruit is a globose capsule, 1.5-3.5mm broad and long, with the remains of the corolla at the base. The capsule can be indehiscent or dehisce irregularly. Each capsule bears up to 4 seeds (3,4,13,18,20).
Seed Description: In the genus Cuscuta, the defining characteristic of the mature embryo is the absence of cotyledons. This may derive from the fact that the first job of the young stem is to search for a host, not to photosynthesize. Each ovary bears four ovules, but one or more may abort, which causes variation in seed size and shape; a dodder seed may have zero, one, or two flat surfaces. C. pentagona seeds are 1-2.2mm long, ovoid and pale yellow. 1000 seeds weigh 0.77-0.87g (3,10,13,18,19).
Dispersal Syndrome: In unspecified members of the genus Cuscuta both germination in the capsule and seeds falling to the ground were observed, leaving water dispersal or other means a possibility for dispersal. Additionally, Cuscuta spp. seeds may be able to pass through the intestinal tract of a sheep intact, remaining viable. Although this method of dispersal is unlikely, it extends the potential dispersal mechanisms to include zoochory (10).
Distinguished by: Cuscuta indecora, C. coryli, and C. gronovii have nearly round ovaries bearing a thickened “stylopodium”, the withered corolla at the apex of the capsule. In C. pentagona, the ovary is depressed-globose with no thickened stylopodium, and the old corolla is at the base of the capsule. Under magnification of 20x, the petals of C. indecora are papillate, the corolla tube is longer than the calyx, and the flower (2.5-4mm long) is larger than C. pentagona. Additionally, the stems are coarse, thicker than C. pentagona. C. gronovii petals are apically round and not inflexed, and the calyx is only about half the length of the corolla tube, same length in C. pentagona. C. coryli, C. cephalanthi, and C. polygonorum are 4-merous, C. pentagona is 5-merous. C. coryli infrastaminal scales are bifid, unlike C. pentagona, and the corolla and calyx are papillate under magnification of 20x. C. cephalanthi has thicker yellow stems, the apically round petals and calyx are a lot shorter than the corolla tube, and the remains of the corolla top the capsule. C. polygonorum calyx and petals are longer than the corolla tube, the calyx lobes apically round. The flowers of C. glomerata are borne in very dense, rope like inflorescences and subtended by very tiny, petaloid bracts and the calyx is unfused (2,3).
Other members of the family in Michigan (number species): Calystegia (5), Convolvulus (1), Cuscuta (8), and Ipomoea (4) (source 2).
Ethnobotanical Uses: C. pentagona is used to obtain a yellow pigment used to dye wool that lasts for years (21). The following uses are for unspecified species of Cuscuta: “An Indian proverb states that the person finding the root of dodder will have access to all the riches of the earth” (10). This statement pertains to the wide use of Cuscuta spp. for medicinal purposes across Asia, from herbal mixtures to treat ovarian cancer and postmenopausal osteoporosis to antifungal and insecticidal applications (13). From another perspective, “The dodder’s rapid development and its stranglehold on and damage to the host have earned it a place in the superstition of many Western countries. The German “Teufelsxwirn” and Dutch “Duivelsnaaigaren” are vernacular names of this sort,” highlights Cuscuta’s standing as a noxious weed in many places (10).
Phylogenetic Information: Convolvulaceae joins four other families of the order Solanales (Montiniaceae, Sphenocleaceae, Hydroleaceae, and Solanaceae), which encompasses 165 genera and 4,080 species. The distribution of Convolvulaceae is extensive worldwide, excluding areas of extreme temperatures—the Sahara and Gobi Deserts, and areas of high latitude (Canada, Greenland, Russia, Antarctica, as well as the southern tip of South America). Convolvulaceae has been noted as the only Asterid I family whose seeds exhibit physical dormancy (10). Cuscuta spp., belonging to the subfamily Cuscutoideae, is the only genus within the family that is parasitic. Its placement in Convolvulaceae is openly debated, but is supported by similar flower morphology (10,11,12) as well as the twining habit.
Interesting Quotation or Other Interesting Factoid not inserted above: Some sources place the genus Cuscuta in its own family, Cuscutaceae (4,5). As other members of the genus Cuscuta, this species is considered a noxious weed in the United States; it is endangered in New Hampshire and Ohio and a special concern species in Wisconsin (5). One of the only woody species that C. pentagona successfully parasitizes is Campsis radicans (18). Many authors consider C. campestris and C. pentagona different species, but recognize that they are very close relatives (3,18,20). The Missouri Botanical Gardens lists the accepted name of this species as Cuscuta obtusiflora Kunth (1), but the source is a general flora, so we leave the species under C. pentagona here. C. pentagona (listed as C. campestris) is the second most abundant native Cuscuta in Canada (13).
Literature and websites used:
- Tropicos.org. Missouri Botanical Garden. 19 Jan 2013 <http://www.tropicos.org/Name/8500698>
- Michigan Flora Online. A.A. Reznicek, E.G. Voss, & B.S. Walters. February 2011. University of Michigan. Web. January 19, 2013. http://michiganflora.net/species.aspx?id=857.
- Fernald, M.L. 1950. Gray’s Manual of Botany, 8th ed. New York: American Book Company.
- Britton, N.L. & H.A. Brown 1970. An Illustrated Flora of the Northern United States and Canada: Volume III. New York, NY: Dover Publications, Inc.
- USDA, NRCS. 2012. The PLANTS Database National Plant Data Team, Greensboro, NC 27401-4901 USA. (http://plants.usda.gov/java/profile?symbol=CUPE3, 01/19/2013).
- Calflora: Information on California plants for education, research and conservation, based on data contributed by dozens of public and private institutions and individuals, including the Consortium of Calif. Herbaria. [web application]. 2013. Berkeley, California: The Calflora Database [a non-profit organization]. Available: http://www.calflora.org/ (Jan 20, 2013).
- Stearn, W.T. 1972. Stearn’s Dictionary of Plant Names for Gardeners. New York, NY: Sterling Publishing Co. Inc.
- Marquardt, E.S. 2009. Foraging and host use of the parasitic plant Cuscuta indecora. Doctoral Thesis/Dissertation: University of Houston. http://gradworks.umi.com/33/71/3371162.html
- McGregor, R.L.1986. Flora of the Great Plains. Lawrence, KS: The University Press of Kansas.
- Kuijt, J. 1969. The Biology of Parasitic Flowering Plants. Los Angeles, CA: University of California Press.
- Yuncker, T.G. 1920. Revision of the North American and West Indian Species of Cuscuta. Illinois Botanical Monographs. 6(2&3):1-141.
- Olmstead, R.G., & S. Stefanović 2004. Testing the phylogenetic position of a parasitic plant (Cuscuta, Convolvulaceae, Asteridae): Bayesian inference and the parametric bootstrap on data drawn from three genomes. Systematic Biology 53(3): 384-399.
- Costea, M. & T.J. François 2005. The biology of Canadian weeds. 133. Cuscuta campestris Yuncker, C. gronovii Willd. ex Schult., C. umbrosa Beyr. ex Hook., C. epithymum (L.) L. and C. epilinum Weihe. Canadian Journal of Plant Science. 298.
- Clark, W.D., R. Moore, & K.R. Stern 1995. Botany. Dubuque, Iowa: Wm. C. Brown Publishers.
- Menninger, E.A. 1970. Flowering Vines of the World. New York, New York: Hearthside Press Incorporated.
- Brown, R.W. 1956. Composition of Scientific Words. Washington, D.C.: Smithsonian Institution Press.
- Robert W. Freckmann Herbarium 2012. Cuscuta pentagona Engelm. University of Wisconsin, Stevens Point. http://wisplants.uwsp.edu/scripts/detail.asp?SpCode=CUSPEN
- Rhui-Chang, F., L.J. Musselman, & U. Plitmann. Flora of China, Vol. 16. http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=200018811
- F., L.J. Musselman 1986. The Genus Cuscuta in Virginia. Castanea 51(3): 188-196.
- 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.
- Tănase, M., C. Sand, & G. Ciortega 2012. The economic impact of Cuscuta: damages and usages. Revista Economică 6: 45-50. http://economice.ulbsibiu.ro/revista.economica/archive/suplimente/Volume6-2012.pdf#page=45
Image Credits (all used with permission):
1) Image of plant habit in Shimane, Japan courtesy of Wildflowers of Shimane http://wildflowersofshimane.web.fc2.com/OUTSIDE_SHIMANE/Cuscuta_pentagona.htm
2) Image of twining stem courtesy of Hiroyuki Morino, downloaded with permission from http://www.flickriver.com/photos/oki_tokyo/4918189162/
3) Image of dry capsules courtesy of Julia Scher, Federal noxious weed disseminules of the U.S. California Department of Food and Agriculture, and Center for Plant Health Science and Technology, USDA, APHIS, PPQ. http://itp.lucidcentral.org/id/fnw/key/FNW_Seeds/Media/Html/fact_sheets/Cuscuta.htm
4) Image of seeds courtesy of Steve Hurst @ USDA-NRCS PLANTS Database http://plants.usda.gov/java/largeImage?imageID=cupe3_001_ahp.tif
5) Species distribution map, derived from the Michigan Flora Online.
Primary Authors: Cristine V. Santanna, John Bradtke, and Lauren Sopher, with revisions and editing by 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