As Rains Ease in the West, Cactuses Shine Brighter Than Ever ~ NYT


Each teddy bear cholla is unique. This species of cactus releases pads and barbs that are carried on the wind to patches of soil where they will take root and grow. Credit: Caity Fares for The New York Times

ANZA BORREGO, Calif. — A cactus in bloom is pure poetry — particularly that famous line by Walt Whitman: “Do I contradict myself? Very well, then I contradict myself.”

In the desert here, the thick, spine-studded paddles of a beavertail cactus look as surly as always, ready to smack you into next week if you get within striking distance.

Yet now, in a superbloom spring that many judge the best in decades, the paddles are topped by dazzling fuchsia flowers the size of teacups, which beckon you closer to feast on the view.

The fish hook cactus lives up to its name, its surface covered with long, curved barbs and a snarl of fibrous hairs; but now it wears a festive garland of creamy white petals smartly trimmed in rouge.

“In some of the dry valleys of Mexico, they have giant columnar cactuses that are hundreds and hundreds of years old,” said Erika Edwards, an associate professor of ecology and evolutionary biology at Brown University who studies photosynthesis in cactuses and other succulents.

While the basic contours of the cactus survival plan have been known for some time, researchers are still unearthing surprising details about how the plants adapt to adversity, and how they subtly manipulate the niches they inhabit and the other creatures they encounter to suit their defense and propagatory needs.

Recently, for instance, scientists have found that as many as 100 species of cactuses are essentially breasts for ants, exuding through tiny nipples in their flesh a minute but irresistible supply of sweet nectar that persuades the insects to nest at the cactal base.

The besotted ants in turn defend their green udder against potentially destructive insect predators; clean away pathogenic fungi and bacteria; fertilize the soil with their nitrogenous waste; and spread the cactus’s seed to new sites.

Other researchers have discovered that a cactus’s roots can operate like sensitive fingers, able to detect when the soil surface has grown dangerously hot and then contracting to yank the entire plant into a lower, slightly cooler position before it’s too late.

Scientists propose that a better understanding of the tricks cactuses apply to handling relentless heat and aridity could prove all too relevant in a world of rising temperatures and water scarcity.

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