Convolvulaceae (Cuscuta)

Family Description

Distribution Map

List of Genera

Digital Atlas of Cuscuta

Mihai Costea at Laurier University in Ontario, Canada has constructed an amazing web site on Cuscuta! Because dodder morphology mostly centers around minute details of the flowers, Mihai has attempted to show "the real thing" instead of line drawings (as seen in Yunker 1932).  The basic morphology is shown using an image fusion methodology that creates the effect of extended depth-of-focus.  Herbarium material was rehydrated and photographed with a stereomicroscope using oblique coherent contrast light.  The priority has been to photograph type material from various herbaria.  Hopefully this site will help "Cuscutologists" as well as those not yet past the "yellow spaghetti" and "mysterious identity" syndromes.

Photographs

Cuscuta americana

1. Photo. Habit of parasites draped over vegetation. St. Vincent Island (Caribbean). Photo by L. J. Musselman.

Cuscuta approximata ssp. approximata

1. Photo. Madrid, Spain. Parasitic on Dorycnium (Fabaceae), Artemisia (Asteraceae) and other hosts. Photo by Miguel A. García.

Cuscuta approximata ssp. macranthera

1. Photo. Greece. Note the elongated and turgid tips of the calyx lobes. Photo of rehydrated herbarium specimen by Miguel A. García.

Cuscuta australis

1. Photo. Photo by J.-M. Hu, Taiwan

Cuscuta angulata

1. Photo. South Africa. Note the prominently angled calyx. Photo of rehydrated herbarium specimen by Miguel A. García.

Cuscuta babylonica

1. Photo. From Turkey. Note the truncate calyx. Photo of rehydrated herbarium specimen by Miguel A. García.
2. Photo. Flowering specimen in hand. Palestine. Photo by L. J. Musselman.
3. Photo. Close-up of flower in face view. Palestine. Photo by L. J. Musselman.
4. Photo. From Crete. Photo of rehydrated herbarium specimen by Miguel A. García.

Cuscuta balansae

1. Cuscuta balansae. From Crete. Note the papillate, dark red calyx lobes. Photo of rehydrated herbarium specimen by Miguel A. García.

Cuscuta campestris

1. Photo. Cáceres, Spain. Photo by Miguel A. García.
2. Photo of plants covering the vegetation along Hwy. 460, Giles Co., VA. Photograph by D. L. Nickrent
3. Photo of plant parasitic on Glechoma hederacea, Urbana, Illinois. Note the twining stems with "bumps" that penetrate the host plant (haustoria). Photograph by Ken Robertson.
4. Photo of fruits. These capsules each contain several seeds that have extremely hard seed coats. The seeds of some species are spread throughout the world as contaminants of grain. Photograph by Ken Robertson.
5. Cucuta campestris parasitic on Trifolium. This microscopic section shows the dodder haustorium (left) penetrating the vascular bundle of the host plant (right). Photograph by D. L. Nickrent.
6. Photo of plants parasitizing ornamental flowers. McPherson Square, Washington, D.C. Photo by Jean Dawson.
7. Photo of plants parasitizing Corchorus in Jordan. Photo by L. J. Musselman.
8. Photo. Close-up of flowers. Plant cultivated on Coleus in the Pennsylvania State University greenhouse. Photo by Joel McNeal.

Cuscuta cephalanthii

1. Photo. Close-up of inflorescences. Gates Co., North Carolina. Photo by L. J. Musselman.
2. Photo. Plant cultivated on Coleus in the Pennsylvania State University greenhouse. Photo by Joel McNeal.
3. Photo. Close-up showing fruits w/ calyptrate corollas and flowers. Although more than half of the flowers are usually 4-merous, 5-merous and 3 merous flowers are not uncommon in the same inflorescence, as this picture shows. Plant cultivated on Coleus in the Pennsylvania State University greenhouse. Photo by Joel McNeal.

Cuscuta chilensis

1. Photo. Masses covering host in the pre-Andes of the northen Valle Central, Chile. Photo by Joel McNeal.
2. Photo. A completely strangled host. Pre-Andes of the northen Valle Central, Chile. Photo by Joel McNeal.
3. Photo. Extensive population on primarily Asteraceous hosts.Pre-Andes of the northen Valle Central, Chile. Photo by Joel McNeal.
4. Photo. Completely covered hosts with mountain backdrop) pre-Andes of the northen Valle Central, Chile. Photo by Joel McNeal.
5. Photo. Close-up of a flower with purple stigmas and bright yellow stamens. Pre-Andes of the northen Valle Central, Chile. Photo by Joel McNeal.
6. Photo. Inflorescence. Pre-Andes of the northen Valle Central, Chile. Photo by Joel McNeal.
7. Photo. Purple-stemmed form on Polygonaceae. Fray Jorge National Park, Chile. Photo by Joel McNeal.

Cuscuta compacta

1. Photo. Great Dismal Swamp, Virginia. Photo by L. J. Musselman.
2. Photo. The endogenously developed inflorescences initially form rows on either side of the stem in this species, eventually forming a dense rope of flowers where once there was stem. Plant cultivated on Coleus in the Pennsylvania State University greenhouse. Photo by Joel McNeal.
3. Photo. Plant cultivated on Coleus in the Pennsylvania State University greenhouse. Photo by Joel McNeal.
4. Photo. Close-up of inforescence. Plant cultivated on Coleus in the Pennsylvania State University greenhouse. Photo by Joel McNeal.

Cuscuta cuspidata

1. Photo of plants parasitizing Gaillardia and being examined by the famous cuscutologist Dr. Miguel A. García and Dr. María Martin. Knox Co., TX, June 23, 2001. Photo by D. L. Nickrent.
2. Photo. Kirkpatrick Ranch, Crosby Co., TX. June 24, 2001. Photo by D. L. Nickrent.
3. Photo. Parasitizing Campsis radicans. Arkansas, August 17, 2001. Photo by D. L. Nickrent.

Cuscuta epilinum

1. Photo. Smothering pre-flowering flax) Cultivated on Linum usitatissimum in the Pennsylvania State University greenhouse. Photo by Joel McNeal.
2. Photo. Inflorescence. Cultivated on Linum usitatissimum in the Pennsylvania State University greenhouse. Photo by Joel McNeal.

Cuscuta epithymum

1. Photo. Note the acute calyx lobes and the elongated stigmas typical of subgenus Cuscuta. Cantabria, Spain. Photo by Miguel A. García.
2. Photo. This specimen corresponds with C. epithymum ssp. kotschyi. Cantabria, Spain. Photo by Miguel A. García.
3. Photo. Dorsal view of pentamerous corolla. Cantabria, Spain. Photo by Miguel A. García.
4. Photo. This specimen corresponds with C. epithymum var. rubella as treated by Yuncker. Madrid, Spain. Photo by Miguel A. García.
5. Photo. Close-up of corolla showing the hypostaminal scales. Photo by Miguel A. García.
6. Photo. A teratological specimen. Cantabria, Spain. Photo by Miguel A. García.
7. Photo. Habit of teratological plant on Thymus. Near Madrid, Spain. Photo by D. L. Nickrent.
8. Photo. Close-up of dissected teratological flowers. New stems grow from the septum region of the gynoecium, emerging between the style lobes. Near Madrid, Spain. Photo by D. L. Nickrent.

Cuscuta europaea

1. Photo. This individual has about an even mix of 4-merous and 5-merous flowers; stem color ranges from yellowish, pinkish, or bright red. Cultivated on Coleus in the Pennsylvania State University greenhouse. Photo by Joel McNeal.
2. Photo.  Habit of the plant parasitizing the host.  The Netherlands. Photo by Rogier van Vugt.
3. Photo. Close-up of flowers. Note the thick, obconic pedicels subtending each flower. Ávila, Spain.Photo by Miguel A. García.

Cuscuta exaltata

1. Photo. Seedling in search of its first host. Seedlings turn green almost immediately after germination in this species. Cultivated in the Pennsylvania State University greenhouse. Photo by Joel McNeal.
2. Photo. Seedling attaching to an Impatiens stem. Cultivated in the Pennsylvania State University greenhouse. Photo by Joel McNeal.
3. Photo. Spike-like inflorescence typical of subgenus Monogyna. Cultivated on Coleus in the Pennsylvania State University greenhouse. Photo by Joel McNeal.
4. Photo. Flowers. Cultivated on Coleus in the Pennsylvania State University greenhouse. Photo by Joel McNeal.
5. Photo. Maturing fruit with calyptrate corolla. Cultivated on Coleus in the Pennsylvania State University greenhouse. Photo by Joel McNeal.

Cuscuta glomerata

1. Photo. As aptly stated by Yunker (1932), the stems of the parasite "disappear early from between the dense, straw-colored, rope-like floral masses which are wound tightly about the stem of the host."  Gensburg Markham Prairie, Cook County, Illinois.  Photo 9 August 1998 by William C. Burger.

Cuscuta grandiflora

1. Photo. Flowering vine.  Bolivia, La Paz, Murillo.  Photo by James Solomon [coll. 16444, 4 April 1987].  Links to Missouri Botanical Gardens TROPICOS Image Library.
2. Photo.  Flowering vine.  Ecuador, Carachi.  Photo by C. Dodson & A. Gentry [coll. 12104, 2 May 1982].  Links to Missouri Botanical Gardens TROPICOS Image Library.

Cuscuta gronovii

1. Photo. Habit of plant draped over vegetation. Near Elizabeth City, Pasquotank Co., North Carolina. Photo by L. J. Musselman.
2. Photo. Cuscuta gronovii var. calyptrata. Maturing fruits topped by the withered corolla; a large-flowered variety that has been introduced to Europe. Cultivated on Coleus in the Pennsylvania State University greenhouse. Photo by Joel McNeal.
3. Photo. Cuscuta gronovii var. calyptrata. Seeds on filter paper at different stages of imbibition. Photo by Joel McNeal.
4. Photo. Parasitized Impatiens capensis with few flowers next to healthy, unparasitized individual with many flowers. Along Spring Creek, Benner Township, Centre County, PA. Photo by Joel McNeal.
5. Photo. Large mass covering over 10 different host species, along Spring Creek, Benner Township, Centre County, PA. Photo by Joel McNeal.
6. Photo. Fruits of typical variety, with withered corolla remaining at the base of the ovoid-conic capsules; also shows a 4-merous flower, present in very low percentages in this species. Along Spring Creek, Benner Township, Centre County, PA. Photo by Joel McNeal.
7. Photo. Inflorescence with typical flowers. Along Spring Creek, Benner Township, Centre County, PA. Photo by Joel McNeal.
8. Photo. Plants with galls from a weevil in the genus Smicronyx; obviously not an effective means of biological control, as evidenced by an inflorescence being produced by one of the galls. Streambank outside of Norfolk, VA. Photo by Joel McNeal.

Cuscuta indecora

1. Photo. Norfolk, Virginia. Photo by L. J. Musselman.
2. Photo, close-up of flower. Norfolk, Virginia. Photo by L. J. Musselman.
3. Photo. Habit. Plant cultivated on Coleus in the Pennsylvania State University greenhouse. Photo by Joel McNeal.
4. Photo. Inflorescence. Plant cultivated on Coleus in the Pennsylvania State University greenhouse. Photo by Joel McNeal.

Cuscuta japonica

1. Photo. A severely parasitized tree. This Asian species has been introducted into the US several times and apparently persists in the Houston, Texas area. Photo Oct. 2001 by Mary L. Ketchersid and Cynthia.Heintze.
2. Photo. Another photo of the dodder covering local vegetation and fence. Photo Oct. 2001 by Mary L. Ketchersid and Cynthia.Heintze.
3. Photo. Close-up of parasite stems. Photo Oct. 2001 by Mary L. Ketchersid and Cynthia Heintze.

Cuscuta lupuliformis

1. Photo. Close-up of flower buds. Bulgaria. Photo by L. J. Musselman.
2. Photo. Habit of plant. Bulgaria. Photo by L. J. Musselman.
3. Photo. Coleus host with the Hop Dodder, cultivated in the Pennsylvania State University greenhouse. Photo by Joel McNeal.
4. Photo. Trailing pink stems with numerous inflorescences. Plant cultivated on Coleus in the Pennsylvania State University greenhouse. Photo by Joel McNeal.
5. Photo. Close-up of magenta-speckled white flowers. Plant cultivated on Coleus in the Pennsylvania State University greenhouse. Photo by Joel McNeal.
6. Photo.  Habit of plant in fruit, parasitizing Rosa. The Netherlands. Photo by Rogier van Vugt.
7. Photo.  Close-up of the fruits (capsules).  The Netherlands. Photo by Rogier van Vugt.

Cuscuta monogyna

1. Photo. Close-up of plant in fruit. Jordan. Photo by L. J. Musselman.
2. Photo. Habit of plant parasitic on Zizyphus. Jordan. Photo by L. J. Musselman.
3. Photo. Granada, Spain. Parasitic on Retama sphaerocarpa (Fabaceae). Photo by Miguel A. García.

Cuscuta nivea

1. Photo. Segovia, Spain. Parasitic on Fumana (Cistaceae). These flowers are only 2.0 mm long! Photo by Miguel A. García.
2. Photo. Segovia, Spain. Flowers in this species are mainly tetramerous. Note the acute papillae and the sharp, cuspidate apical projections of the corolla lobes. Photo by Miguel A. García.

Cuscuta obtusiflora

1. Photo. Inflorescences and close-up of flowers here and here. Plants growing on Ludwigia sp. in a marsh near Rio de la Plata, Argentina. Photo by Joel McNeal.
2. Photo. Fruits from plants growing on Ludwigia sp. in a marsh near Rio de la Plata, Argentina. Photo by Joel McNeal.
3. Photo. Flowering plant. Brazil. From the Neotropical Live Plant Photos site. Photo ID 6064. Photo by Robin Foster.

Cuscuta palaestina

1. Photo. Kalamata, Peloponnesus, Greece. Note the trimerous flowers and the cucullate corolla lobes. Photo by Miguel A. García.

Cuscuta pedicellata

1. Photo. Plants in hand. Sudan, Africa. Photo by L. J. Musselman.

Cuscuta planiflora

1. Photo. Morocco. This specimen corresponds with C. planiflora var. papillosa. The flower is densely covered with papillae and the calyx lobes are turgid. Photo by Miguel A. García.
2. Photo. Murcia, Spain. Note the narrow, turgid calyx lobes. Photo by Miguel A. García.
3. Photo. Almería, Spain. Seedling. Note that Cuscuta lacks cotyledons. The yellow-colored shoot in the foreground develops into the twining stem of the parasite. The The distal club-shaped end is a tuberous organ terminates with a small tip. Whether this tip represents a root is still unclear (see Lyshede, 1986, Ber. Deutsch. Bot. Ges. Bd. 99:105). Photo by Miguel A. García.

Cuscuta polygonorum

1. Photo. Inflorescences. Flowers are predominantly 4-merous, unlike C. pentagona and C. campestris, with which it is sometimes lumped. Plant cultivated on Coleus in the Pennsylvania State University greenhouse. Photo by Joel McNeal.

Cuscuta rausii

1. Photo. Karpathos Island, Greece. Note the tetramerous flowers with long pedicels. Photo of rehydrated herbarium specimen by Miguel A. García.

Cuscuta reflexa

1. Photo showing habit of plant, cultivated on Ficus benjamina in the Botanical Garden Graz (Austria). See article on floral development and morphology by Prenner et al. (2002). Photo by Gerfried Deutsch.
2. Photo showing racemose inflorescence. In India and neighboring areas, this dodder is cultivated on Pelargonium because its flowers are similar to Convallaria. Photo by Gerfried Deutsch.
3. Photo. Close-up of the flowers of "giant dodder", the corolla of which can exceed 7 mm in length. The flowers have a strong odor of honey. Photo by Gerfried Deutsch.

Cuscuta rostrata

1. Photo. Habit of plant. Smyth Co., Virginia. Photo by L. J. Musselman.
2. Photo. Close-up of inflorescence. Smyth Co., Virginia. Photo by L. J. Musselman.
3. Photo. Habit, with noticeable clusters of large, white flowers. Plant cultivated on Coleus in the Pennsylvania State University greenhouse. Photo by Joel McNeal.
4. Photo. Inflorescences and bright orange stems. Growing on Rubus on roadside along highest elevations of Blue Ridge Parkway, North Carolina. Photo by Joel McNeal.
5. Photo. Habit on Rubus, the host on which it is almost always found on or near. Highest elevations of Blue Ridge Parkway, North Carolina. Photo by Joel McNeal.
6. Photo. Flowers, showing protruding beak on ovaries. Growing on Rubus on roadside along highest elevations of Blue Ridge Parkway, North Carolina. Photo by Joel McNeal.
7. Photo. Fruits, with distinctive beak. Plant cultivated on Coleus in the Pennsylvania State University greenhouse. Photo by Joel McNeal.

Cuscuta saccharata

1. Photo.  Inflorescence.  Nicaragua, Managua.  Photo by W. D. Stevens [coll. 20950, 30 November 1981].  Links to Missouri Botanical Gardens TROPICOS Image Library.

Cuscuta sandwichiana

1. Habit, close-up of stems/haustoria, flowers. Link goes to University of Hawaii Vascular Plant Families.

Cuscuta salina

1. Photo. Cultivated on Beta vulgaris. Photo by Alison Colwell.

Cuscuta somaliensis

1. Photo. Kenya. Photo of herbarium specimen by Miguel A. García.
2. Photo. Kenya. Close-up pentamerous, papillate flower. Photo of rehydrated herbarium specimen by Miguel A. García.

Cuscuta tasmanica

1. Photo. Habit of plant twining on a small saltmarsh host. Photo by Greg Jordan. See Key to Tasmanian Dicots.
2. Photos. Close-up of flower of this species. Photo by Greg Jordan.

Cuscuta triumvirati

1. Photo. Granada, Spain. Close-up of pentamerous flower. Note the blunt calyx lobes. Photo by Miguel A. García.

Controlling Cuscuta (Dodder) Infestations

Phylogeny

The sole parasitic genus of Convolvulaceae is Cuscuta that has sometimes been placed in its own family, Cuscutaceae. Analysis of sequence data from four chloroplast gene regions resulted in Cuscuta being nested within Convolvulaceae (Stefanovic and Olmstead 2000), thus the classification of APG2 is supported.

References