<p>Rather than digging out dandelions in my lawn, I just pull off the flower heads and buds. Will this work? Common dandelions, or Taraxacum officinale, are born of a tenacious breed of plant, better equipped than most to survive and propagate, gardening authorities agree. The accepted wisdom is that removing the root system or using a broad-leaf herbicide are the only ways to defeat them.<br /><br /></p>.<p>But the central root grows very deep, usually half a foot to 18 inches but sometimes 10 or 15 feet, and the temptation is to seek a shortcut. Pulling off flower heads, known to gardeners as deadheading, can encourage more shoots and buds, as it directs the plant’s resources from the developing flower and back to the infrastructure.<br /><br />In ornamental plants, deadheading is usually done after the flower has germinated and become unattractive, but the removal of flowers and buds at any time can have the same effect. With dandelions in particular, deadheading seems to only encourage a more vigorous growth of the crown of leaves growing concentrically around the top of the central root. New flower stalks soon follow. <br /><br />Even cutting off the entire crown at or below the soil level does not discourage the plant from regenerating and vigorously producing new shoots, stalks and flowers, if a mere inch of root is left behind. The plants can survive and grow for years.<br /><br />To frustrate weeders further, there are anecdotal reports that the pulled-off flowers can continue to produce viable seeds if picked at the right stage and left on the lawn. And it takes only a single winged seed from the compound flower, produced by one of the hundred or more segments of the mature dandelion flower, to produce the next dandelion. The seeds do not even have to be pollinated. The bottom line is that dandelion removal still requires radical surgery or chemical warfare.<br />C Claiborne Ray<br /><br />A piece of a sea monster<br />Five million years ago, a massive sea monster may have eviscerated sharks and whales using gigantic teeth. Murray Orr stumbled on this not-so-pearly-white, centre, in February while exploring Beaumaris Bay, near Melbourne, Australia. “For a moment, it looked like an artillery shell, and I thought I might blow my arm off,” he said in an email.<br /><br />When he returned home, Murray had Erich Fitzgerald, a paleontologist at the nearby Museum Victoria, look at the tooth. Erich determined that the fossil belonged to a relative of an extinct group of marine predators called Livyatan melvillei, which were 60 feet long and weighed 88,000 pounds. Murray donated the tooth to the museum.<br />Nicholas St Fleur<br /><br />Forests rise to the challenge of CO2<br />A new study reports that recently established forests on abandoned farmland in Latin America, if allowed to grow for another 40 years, would probably be able to suck at least 31 billion tonnes of carbon dioxide out of the atmosphere.<br /><br />That is enough to offset nearly 2 decades of emissions from fossil-fuel burning in the region. Abandoning additional pastures and allowing them to revert to tropical forest could soak up another 7 billion tonnes of the gas, the scientists found.<br /><br />Their paper offers the most detailed estimates to date for a promising approach to combating climate change. Many Latin American governments have promised to encourage forest regrowth, as well as to combat the destruction of existing forests, in their long-term climate plans. But how hard they will push on either issue is unclear.<br /><br />“This is a potential contribution that is sitting right under our noses,” said the lead author, Robin L Chazdon, a University of Connecticut ecologist, who is working at the International Institute for Sustainability in Rio de Janeiro.<br />Justin Gillis<br />The New York Times</p>
<p>Rather than digging out dandelions in my lawn, I just pull off the flower heads and buds. Will this work? Common dandelions, or Taraxacum officinale, are born of a tenacious breed of plant, better equipped than most to survive and propagate, gardening authorities agree. The accepted wisdom is that removing the root system or using a broad-leaf herbicide are the only ways to defeat them.<br /><br /></p>.<p>But the central root grows very deep, usually half a foot to 18 inches but sometimes 10 or 15 feet, and the temptation is to seek a shortcut. Pulling off flower heads, known to gardeners as deadheading, can encourage more shoots and buds, as it directs the plant’s resources from the developing flower and back to the infrastructure.<br /><br />In ornamental plants, deadheading is usually done after the flower has germinated and become unattractive, but the removal of flowers and buds at any time can have the same effect. With dandelions in particular, deadheading seems to only encourage a more vigorous growth of the crown of leaves growing concentrically around the top of the central root. New flower stalks soon follow. <br /><br />Even cutting off the entire crown at or below the soil level does not discourage the plant from regenerating and vigorously producing new shoots, stalks and flowers, if a mere inch of root is left behind. The plants can survive and grow for years.<br /><br />To frustrate weeders further, there are anecdotal reports that the pulled-off flowers can continue to produce viable seeds if picked at the right stage and left on the lawn. And it takes only a single winged seed from the compound flower, produced by one of the hundred or more segments of the mature dandelion flower, to produce the next dandelion. The seeds do not even have to be pollinated. The bottom line is that dandelion removal still requires radical surgery or chemical warfare.<br />C Claiborne Ray<br /><br />A piece of a sea monster<br />Five million years ago, a massive sea monster may have eviscerated sharks and whales using gigantic teeth. Murray Orr stumbled on this not-so-pearly-white, centre, in February while exploring Beaumaris Bay, near Melbourne, Australia. “For a moment, it looked like an artillery shell, and I thought I might blow my arm off,” he said in an email.<br /><br />When he returned home, Murray had Erich Fitzgerald, a paleontologist at the nearby Museum Victoria, look at the tooth. Erich determined that the fossil belonged to a relative of an extinct group of marine predators called Livyatan melvillei, which were 60 feet long and weighed 88,000 pounds. Murray donated the tooth to the museum.<br />Nicholas St Fleur<br /><br />Forests rise to the challenge of CO2<br />A new study reports that recently established forests on abandoned farmland in Latin America, if allowed to grow for another 40 years, would probably be able to suck at least 31 billion tonnes of carbon dioxide out of the atmosphere.<br /><br />That is enough to offset nearly 2 decades of emissions from fossil-fuel burning in the region. Abandoning additional pastures and allowing them to revert to tropical forest could soak up another 7 billion tonnes of the gas, the scientists found.<br /><br />Their paper offers the most detailed estimates to date for a promising approach to combating climate change. Many Latin American governments have promised to encourage forest regrowth, as well as to combat the destruction of existing forests, in their long-term climate plans. But how hard they will push on either issue is unclear.<br /><br />“This is a potential contribution that is sitting right under our noses,” said the lead author, Robin L Chazdon, a University of Connecticut ecologist, who is working at the International Institute for Sustainability in Rio de Janeiro.<br />Justin Gillis<br />The New York Times</p>