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Thursday, May 20, 2010

Dandelion, Taraxacum officinale

Even digital botanic gardens have weeds - in the case of mine, dandelions Taraxacum officinale agg. Dandelions are cosmopolitan weeds and long ago the European species was introduced into the United States, where it has become a major weed. Part of this plant's success can be attributed to its reproductive system, where it sets seed without the need for pollination, and its prolific seed production is coupled to an extremely effective wind-assisted seed dispersal mechanism. Back in 2007 two researchers at Purdue University in Indiana, Tamara McPeek and Xianzhong Wang, were curious to know how this plant might fare in future world where carbon dixide levels were double those of today - which is likely to occur around 2080. For the grandchildren of today's gardeners, their findings make ominous reading. The plants produced 83% more inflorescences and 32% more seeds that were larger, germinated better and established faster. Not only that, but they travelled further because their parachute of hairs (the pappus) was larger and carried the seeds further on the wind. Source: Tamara McPeek and Xianzhong Wang (2007) Reproduction of Dandelion (Taraxacum officinale) in a higher CO2 environment. WEED SCIENCE Volume: 55 Issue: 4 Pages: 334-340