Featured Research

from universities, journals, and other organizations

World's Largest Flower Evolved From Family Of Much Tinier Blooms

Date:
January 12, 2007
Source:
Harvard University
Summary:
The plant with the world's largest flower -- typically a full meter across, with a bud the size of a basketball -- evolved from a family of plants whose blossoms are nearly all tiny, botanists write this week in the journal Science. Their genetic analysis of rafflesia reveals that it is closely related to a family that includes poinsettias, the trees that produce natural rubber, castor oil plants and the tropical root crop cassava.

Rafflesia arnoldii, Sumatra.
Credit: Photo Jeremy Holden, July 2005

The plant with the world's largest flower -- typically a full meter across, with a bud the size of a basketball -- evolved from a family of plants whose blossoms are nearly all tiny, botanists write this week in the journal Science. Their genetic analysis of rafflesia reveals that it is closely related to a family that includes poinsettias, the trees that produce natural rubber, castor oil plants, and the tropical root crop cassava.

The team from Harvard University, Southern Illinois University, the Smithsonian Institution, and the University of Wisconsin was led by Harvard's Charles C. Davis.

"For nearly 200 years rafflesia's lineage has confounded plant scientists," says Davis, an assistant professor of organismic and evolutionary biology in Harvard's Faculty of Arts and Sciences. "As a parasite living inside the tissue of a tropical vine, the plant lacks leaves, shoots, or roots, making it difficult to compare to more conventional plants. Most efforts to place plants in the botanical tree of life in the past 25 years have tracked ancestry using molecular markers in genes governing photosynthesis. Rafflesia is a non-photosynthetic parasite, and those genes have apparently been abandoned, meaning that to determine its lineage we had to look at other parts of the plant's genome."

Davis and his colleagues determined that over an estimated 46 million years, rafflesia's blooms, which now weigh up to 15 lbs., evolved at an accelerated pace. However, after increasing in size by a factor of roughly 79, the plant then reverted to a more sedate evolutionary pace.

This evolutionary spurt is one of the most dramatic size changes ever reported among eukaryotes; if humans were to undergo comparable evolutionary growth, Davis says, an average man would end up some 146 meters tall, roughly the height of the Great Pyramid of Giza.

Because rafflesia lacks the genes most commonly used to trace plant ancestry, the scientists delved deeper into the genome, looking at some 11,500 base pairs of DNA to determine that the giant flower's closest relatives are in the Euphorbiaceae family, many of which have blossoms just a few millimeters in diameter.

"The power of nucleic acid comparisons is revealed as well as ever in this stunning deduction," says noted botanist Peter H. Raven, president of the Missouri Botanical Garden in St. Louis, who was not involved in this research. "The massive increase in flower size is one of the most significant among living organisms, and could never have been deduced by conventional methods."

Found growing on the jungle floor in parts of southeastern Asia, rafflesia is unusual in more than just its flower's size. A parasite, it derives its nutrients from a plant in the grapevine family and lacks leaves, stems, or roots. Even more shocking is the plant's carcass-like appearance: Its blooms are a mottled blood red, reek of decaying flesh, and in some cases even emit heat, much like a recently killed animal. These traits help the flower attract the carrion flies that pollinate it.

"While it's surprising to find this giant plant evolved from a family typified by much smaller blossoms, rafflesia is unusual enough that it's frankly been difficult to imagine it fitting neatly into any plant family," Davis says. "Many botanists had refused to even speculate on where this botanical outlier might fit into the tree of life."

Rafflesia was first discovered in the Sumatran rain forest some 180 years ago by Sir Stamford Raffles, governor of the East India Company's establishments in Sumatra, and Joseph Arnold, a naturalist and physician. Shortly before Arnold died of malaria on that same expedition, he described rafflesia as "the greatest prodigy of the vegetable world," adding, "To tell you the truth, had I been alone, and had there been no witnesses, I should think I would have been fearful of mentioning the dimensions of this flower, so much does it exceed every flower I have ever seen or heard of."

Davis' co-authors on the Science paper are Maribeth Latvis of Harvard's Department of Organismic and Evolutionary Biology; Daniel L. Nickrent of Southern Illinois University; Kenneth J. Wurdack of the Smithsonian Institution; and David A. Baum of the University of Wisconsin. Their work was supported by the National Science Foundation, the Department of Organismic and Evolutionary Biology at Harvard, and the Michigan Society of Fellows.


Story Source:

The above story is based on materials provided by Harvard University. Note: Materials may be edited for content and length.


Cite This Page:

Harvard University. "World's Largest Flower Evolved From Family Of Much Tinier Blooms." ScienceDaily. ScienceDaily, 12 January 2007. <www.sciencedaily.com/releases/2007/01/070111181726.htm>.
Harvard University. (2007, January 12). World's Largest Flower Evolved From Family Of Much Tinier Blooms. ScienceDaily. Retrieved October 20, 2014 from www.sciencedaily.com/releases/2007/01/070111181726.htm
Harvard University. "World's Largest Flower Evolved From Family Of Much Tinier Blooms." ScienceDaily. www.sciencedaily.com/releases/2007/01/070111181726.htm (accessed October 20, 2014).

Share This



More Plants & Animals News

Monday, October 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

White Lion Cubs Born in Belgrade Zoo

White Lion Cubs Born in Belgrade Zoo

AFP (Oct. 20, 2014) Two white lion cubs, an extremely rare subspecies of the African lion, were recently born at Belgrade Zoo. They are being bottle fed by zoo keepers after they were rejected by their mother after birth. Duration: 00:42 Video provided by AFP
Powered by NewsLook.com
Traditional Farming Methods Gaining Ground in Mali

Traditional Farming Methods Gaining Ground in Mali

AFP (Oct. 20, 2014) He is leading a one man agricultural revolution in Mali - Oumar Diatabe uses traditional farming methods to get the most out of his land and is teaching others across the country how to do the same. Duration: 01:44 Video provided by AFP
Powered by NewsLook.com
Goliath Spider Will Give You Nightmares

Goliath Spider Will Give You Nightmares

Buzz60 (Oct. 20, 2014) An entomologist stumbled upon a South American Goliath Birdeater. With a name like that, you know it's a terrifying creepy crawler. Sean Dowling (@SeanDowlingTV) has the details. Video provided by Buzz60
Powered by NewsLook.com
Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

3BL Media (Oct. 20, 2014) Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-fuel Impala Video provided by 3BL
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins