Thursday, August 9, 2012

You Will Know It's Euphorbia By Its Glands

Euphorbia characis 'Glacier Blue' PP19027

Euphorbia is one of the world's largest genera with over 2000 known species. They're so diverse in appearance you'd hardly know they are all related. Compare the popular poinsettia (Euphorbia pulcherrima) to Euphorbia canariensis to Euphorbia milii to Euphorbia serrata.

See what I mean? You might even have some growing in your yard like the Euphorbia cyathopora under my grape vines or Euphorbia maculata among the squash. Regardless of their differences, they all share characteristics with one called Euphorbia antiquorum, the type species. If you don't have one handy to compare, you'll know you've got Euphorbia by its glands. You might need a magnifying glass.

Carl Linneaus (1707-1778) devised the system of sorting and organizing plants according to their sexual apparatus. A better method was never contrived, nor shall be.

Euphorbia flowers are surrounded by modified leaves called bracts. The Christmas poinsettia is a good example. Those big floppy red things are not flowers, but bracts. In other words, they're false flowers. If you peer between the bracts, you'll find the true flowers. They're tiny. Each euphorbia flower is uni-sexual, either male or female. Sometimes both sexes occur on the same plant; sometimes on different plants. Anyway, euphorbia flowers have glands. The horn-shaped glands of E. amygdaloides are good examples. All euphorbia glands are not horn-shaped, but you get the idea.

Euphorbias also share another trait: sticky, milky sap. Depending on the species, the sap (latex) can be very caustic and even poisonous. Contact with skin, to say nothing of the eyes and sensitive tissue, may be very irritating. Ingesting it can make one throw up, or worse. For this reason, euphorbias are often called "spurge." Rhymes with "purge."

Ironically, the name Euphorbia is derived from two Greek words combined meaning "good pasture." But the genus wasn't named because of its edibility. It was named to honor Euphorbus (Dr. Goodpasture), the personal physician of King Juba II of Numidia. Juba (c. 50BC - 23AD) married the daughter of Anthony and Cleopatra. Numidia was in North Africa.

Juba was a scholar and best-selling author of books on history, natural history, geography, travel, language and the arts. It was natural that he named a plant known to be a powerful laxative for his doctor. Over 1700 years later, Linneaus could do no better, so he gave the name to the entire genus.

Euphorbia is distributed world-wide. Over 60 species thrive in North America. Whether native or introduced, euphorbias grow in virtually every state and province in the U.S. and  Canada.

Euphorbia enthusiasts may choose their favorites for many reasons: their floral beauty, foliage, large size, small size, drought-tolerance, low maintenance, or because some look just plain weird. There's a euphorbia for everyone.

One might wonder whether euphorbias are suitable plants for the home and garden considering the troubling sap. Certainly any gardener should learn about plants and their possible hazards before growing them. But one thing I've observed about Euphorbia is the more formidable ones sport menacing spines that say, "Don't mess with me without gloves!" With that in mind, take care and have fun.

With so many different species, it would be difficult to summarize planting details and growing conditions. But as time goes by, I'll detail a few of them in future articles.

Until then, you can learn more about them at The International Euphorbia Society.

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