– Euphorbia aureoviridiflora (2010)

By Susan Carpentier (July 2010)

Euphorbia aureoviridiflora was first named E. neohumbertii v. auero-viridiflora before it was moved to its own species.

The geographic range of Euphorbia aureoviridiflora is southwest Madagascar, restricted to the Montagne des Francais near Antsirananaon, but it may also occur further south, where this plant grows in the full sunshine on rocks and in the forest, too.

The habitat for E. aureoviridiflora, a Madagascar native, is in the “tsingy” rock found in Tsingy de Bemaraha National Park. The formation of these unusual rocks began some 200 million years ago, when layers of calcite accumulated at the bottom of a Jurassic lagoon, forming a thick limestone bed. Later tectonic activity elevated the limestone, and as sea levels fell during the Pleistocene ice ages, even more of the limestone was exposed.

No longer under water, the ancient sediments were carved by monsoon rains, which washed softer rocks away and left tougher rocks standing. Meanwhile, groundwater carved caves below the surface. As cave ceilings gave way, canyons formed between rocky towers. Today, the limestone formation shows a combination of jagged spires and rounded surfaces. (Earth Observatory website.)

There are no current measures to protect this species outside the northern reserves. Major threats to Euphorbia aureoviridiflora include habitat degradation and fire.

After being in shade for a week, this plant in my collection will be put in full morning sun. Next winter it will be placed under lights and watered once a month.

The information for this article was taken from the website of the International Union for Conservation of Nature and Natural Resources.