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Showing posts from September, 2019

The African Tree of Life

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“Wisdom is like a baobab tree; no individual can embrace it."
Some trees are strongly associated with the places in which they grow, so much that they become symbols of the places themselves; think of the Coast Redwoods of California, the Pehuen or Monkey Puzzle of the Andean foothills of Chile, or the various species of Australian Eucalyptus. One tree that is distinctly recognizable in the drier parts of sub-Saharan Africa is the Baobab, Adansonia digitata. Baobabs are naturally distributed from the Atlantic to the Red Sea, and to the northernmost part of South Africa. Like other organisms that are so well known that they have been taken for granted, the massive Baobabs still have secrets to reveal. Some of the trees might be a newly described species, Adansonia kilima, according to the latest genetic analysis. Baobabs provide significant environmental benefits to wildlife: safety and a nesting place for many creatures, nectar for the species’ fruit bat and insect pollinators, a…

Living on the Edge: the Cottontop Cactus

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 The Cottontop Cactus, Echinocactus polycephalus, is a moderate-sized barrel cactus that lives in some of the driest areas of North America. There are two similar subspecies: polycephalus,the most widespread, found in parts of California, Nevada, Utah, Arizona and northern Mexico, and xeranthemoides, found near the Grand Canyon in southeastern Nevada and Northern Arizona. “Way over to Hell and gone” is an apt description of the species’ habitat. It occurs from the spectacularly desolate mountains overlooking Death Valley to the wretchedly arid flats of the Cabeza Prieta National Wildlife Refuge. Cottontop Cactus grow in arid or hyper-arid landscapes that usually receive no more than 5 inches of precipitation per year. In the Mojave Desert the species must survive exclusively on winter rainfall, but plants in the Sonoran Desert occasionally experience summer thunderstorms during the monsoon season. In the hot, stony wastes in which they grow, the sparse rains quickly drain away or eva…