Aquarium of the Pacific - Online Learning Center - Species Print Sheet
Saltmarsh dodder is one of eight California native species of Cuscuta. This species grows as a leafless, rootless, yellow or orange vine. It cannot photosynthesize to satisfy its own energy needs so it gets its nutrients and water from its hosts, salt tolerant halophytes, (such as pickleweed, Salicornia virginica), that grow in tidal coastal saltmarshes. Such parasites are called holoparasites. Although the plants have little if any chlorophyll and no leaves, they are still classified as true plants.
At the Aquarium
Information on saltmarsh dodder is included in the Online Ocean Learning Center because this distinctive yellow or orange plant is often seen in California saltmarshes.
West coast including California, Oregon, and Washington. Also Utah, Nevada, and Arizona.
Primary habitats for these plants are saltmarshes and inland alkaline flats.
The five-petaled flowers that grow in dense clusters are tiny, waxy, and white in color. They appear sporadically among the vines. Mature vines are tangled mats of tender thread-like stems that are typically yellow or bright orange. Colin Purrington, a botanist who studies saltmarsh dodder, has described the mature vines as “superficially resembling cooked spaghetti with a light coating of orange tomato sauce”.
Diet and Feeding
Saltmarsh dodder is a holoparasite. Because it lacks leaves, it is unable to photosynthesize. It gets its nutrients and water from its host.
Male and female reproductive organs are found on the same plant. Fertilized seeds drop off the vines and may stay in the same location or they may float to another location carried by winds and currents, or be carried by wrack, (floating saltmarsh vegetation), or perhaps by birds. There are small hooks on the seeds that act like Velcro, enabling the seeds to attach to the floating wrack until the wrack is deposited somewhere in the saltmarsh. Leafless seedlings emerge from the seed and start to twine or twist counterclockwise. The young vines either make immediate contact with a host or seek out a host.
Once contact is made, modified roots called haustoria develop from swellings that are formed in the concave surfaces of the coiling tendrils. The haustoria puncture the stems of the host to penetrate into the tissues from which they will extract water and nutrients. The effect on the host is usually only stunted growth; however, if the mat becomes too dense, the host will be blocked from the sunlight it needs to photosynthesize and it will not survive.
Initially, the germinated seeds develop into non-parasitic plants. They become parasitic when they make contact with a host.
Because it lacks the ability to make chlorophyll, saltmarsh dodder has developed ways to get nutrients from other plants as described in the section on reproduction.
Saltmarsh dodder usually lives only 10 days as a non-parasitic plant if it is unable to find a host. The exact length of time is influenced by temperature, humidity, and perhaps, the size of the original seed. It is deciduous once it finds a host.
Giant dodder, Cuscula reflexa, is a species of dodder that is native to Asia where it is a serious parasite of peach and citrus orchards. The California Department of Food and Agriculture lists it as an ‘A’ noxious weed. One of the requirements for such a listing is that the plant must be eradicated. In order to protect California’s citrus crop, this was done very rapidly when it was discovered in the state so as to protect the state’s economically valuable citrus crop.
Saltmarsh dodder is closely related to morning glory.