Invasion Biology Introduced Species Summary Project

Introduced Species Summary Project
Dandelion (Taraxacum officinale)

Common Name: Dandelion

Scientific Name: Taraxacum officinale

Classification: Plantae

Phylum or Division: Magnoliophyta
Class: Magnoliopsida
Order: Asterales
Family: Asteraceae
Subfamily:

Identification: Dandelion derives its name from the french term ‘dent de lion’ meaning ‘tooth of the lion’. Dandelions are perennial, herbaceous plants that grow best in moist, sunny areas found in all parts of the northern temperate zone. The plant grows year round but goes dormant in areas that experience a cold winter. The dandelion taproot, thick, sturdy and dark brown, can penetrate the soil up to 10 to 15 feet. The buds grow from the uppermost area of the root where a tight crown is formed. Here additional plants can grow even if the root has been cut into the soil and is only one inch in length. Leaves, shiny and hairless, are 3 to 12 inches long and ½ to 2 ½ inches wide and always form a basal rosette shape, meaning they all branch out from the center. They resemble canine teeth pointing upright or backwards. The flowering stalk can reach lengths from 6 to 24 inches. The head contains 100 to 300 ray flowers and when cut off, a bitter, milky substance leaks out from the stem. Beneath the floret of bright golden yellow, five tiny petals sit above a tube filled with an abundance of nectar.

Original Distribution: Though the dandelion has been carried from place to place since before written history, it can at least be said that the plant is native to Europe and Asia. The earliest recordings can be found in Roman times and use has been noted by the Anglo Saxon tribes of Britain and the Normans of France. In the tenth and eleventh centuries there is mention of dandelions used for medicinal purposes in the works of Arabian physicians.

Current Distribution: Dandelions have been established in the Americas, Australia, and New Zealand amongst many other temperate regions such as Austria, Italy, Poland, and Turkey and throughout the United States. India, for example has largely cultivated the plant to use as a remedy for liver problems.

Dandelions can grow just about anywhere, namely fields, lawns, forests, gardens or even wastelands. They tend to grow more in areas laden with sunlight rather than under trees or shady spots. The plant can be found more commonly in disturbed areas such as an avalanche site, a burned forest and marshlands to name a few and anywhere from sea level to high alpine elevations.

Site and Date of Introduction: Dandelions have spread throughout the northern hemisphere for so long that it is difficult to determine their nonnative status. It has been noted however, that the Puritans found dandelions to be so useful that they brought them to settle in the new county.

Mode(s) of Introduction: Throughout history, dandelions have been purposely carried across oceans and continents by human beings. European settlers brought these plants intentionally to America. Ships that came ashore to the New World undoubtedly brought soil and seeds along including the seeds of dandelions. While the plant spread discretely in a pant cuff or in a boot sole, it was also an invited species.

Reason(s) Why it has Become Established: There are many various reasons why the dandelion has become established. The most intended purposes of the dandelion was for medicine, food and wine. In the 17^th century when dandelions were brought to the New World, they were mainly used by the Puritans as a source of medicine. Dandelion was not valued as a food commodity but instead as hosting a variety of health benefits. As the men toiled the land, the women would garden. Though they did not understand why, the leaf, root and flower were believed to have significant results in alleviating ailments. Dandelion was also cultivated because it was a plant they were familiar with and could trust in this foreign land. Thus, the woman planted dandelion seeds for its medicinal benefits and to spread a flower that reminded them of home.

The dandelion species is not easy to contain. Just by blowing the puffball, the head flies away spreading a couple hundred seeds up to hundred of miles away depending on the wind strength. It was reported that by 1672, the plant was well established in New England. Spaniards brought dandelion to California and Mexico, while the French introduced them to Canada helping the plant to move swiftly across the continent.

Ecological Role: Dandelion are associated with the following common shrubs, grasses, and forbs; common snowberry, Wood’s rose, russet buffalo berry, blueberry, chokecherry, black sagebrush, Wyoming big sagebrush, Oregon-grape, rough fescue, Idaho fescue, slender wheatgrass, prairie Junegrass, timber danthonia, Richardson’s needlesgrass, tufted hairgrass, bluegrass, aster, willowweed, prairie smoke avens, small-leaf angelic, Colorado columbine, rhexia-leaved paintbrush, Oregon fleabane to name some.

While dandelion commonly cultivate in disturbed areas, the length of time the plant remains prevalent varies from ecosystem to ecosystem. It may reach a peak after a few years or last steadily for as much as ten. After harvesting, dandelion is a predominant species. Once an area has been overgrazed, dandelions germinate. When there has been overgrazing, dandelion appear. However, dandelion would not exist on rangelands because they cannot withstand competition for water, nutrients, and sunlight.

Benefit(s): Small birds feed off of the dandelion seeds. Pigs, goats and rabbits will eat the plant. The flower proves nectar for honey bees.

The dandelion has countless health benefits and palatable applications. Europeans used the plant to treat fevers, boils, eye problems, diarrhea, fluid retention, liver congestion, heartburn, and skin ailments. Dandelion was used in China, India and Russia to treat breast problems, liver diseases, appendicitis and digestive problems.

Dandelion is seen as aiding digestion due to its bitter principles thought to stimulate salivary and gastric juices. The root can improve bile flow which would help alleviate liver congestion, bile duct inflammation, hepatitis, gallstones and jaundice. Dandelion leaves create diuretic activity which can cause considerable weight loss. Studies have shown that the plant can produce antibodies to cancer and can buffer blood glucose levels for diabetics.

All parts of the plant can be eaten and are often found in salads, roasted, fried, mixed in pancakes or made into wine, tea, or a coffee-like drink. Dandelions have a taste similar to chicory or endive with a bitter tinge.

Threat(s): The dandelion has a low ecological impact and provides no real damage to the ecosystem. The major negative aspect of the dandelion is the difficulty in exterminating it in yards or places where people do not want the plant to grow. Dandelions are often considered an annoying weed and are found most commonly in highly disturbed ecosystems such as lawns.

Control Level Diagnosis: Dandelions have a fairly low threat to ecosystems. It seems only necessary to control the species when seen as an aesthetic problem or ‘weed’.

Control Method: Dandelions are one of the most difficult weeds to control since the seeds can spread quickly and easily by wind. The seeds do not need to be planted and can germinate on their own under most conditions. It is best to attempt to stop the proliferation when dandelions are still seedlings because once established, the specie is very hard to disrupt. The ways to control dandelion growth are mainly sweep tillage and disking, crop competition, forage management and herbicide options. The most successful approach is to combine a cropping program with the use of herbicides to prevent dandelion establishment. With good crop competition, dandelion germination can be stifled. Using herbicide application during the fall is most effective. The measures that can be taken in a direct seeding system are; pre-seeding, early spring in-crop, pre-harvest, post-harvest, summer fallow, termination of perennial forage. To control dandelions, a combination of approaches should be taken seriously since the plant can establish itself rapidly.

References and Image Sources:

http://www.mwpubco.com/Sanchez%20-%20Text%20pages%201-11.pdf

http://www.geocities.com/chadrx/dande.html

http://www.botanical.com/botanical/mgmh/d/dandel08.html

http://www.econetwork.net/~wildmansteve/Plants.Folder/Dandelion.html

http://www.wssa.net/photo&info/larrymitich_info/dandelion.html

http://en.wikipedia.org/wiki/Dandelion

http://www.fs.fed.us/database/feis/plants/forb/taroff/botanical_and_ecological_characteristics.html

http://ipcm.wisc.edu/uw_weeds/extension/articles/dandelion.htm

http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex2511

Author: Dara Hourdajian
Last Edited: November 13, 2006

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