Botany Photo of the Day

Euphorbiaceae consists of about 320 genera and between 7500 and 9000 species, making it one of the largest plant families. The family is for the most part comprised of herbs, but it includes several tree and shrubby species among its ranks as well. Though the majority of species are native to either southeastern Asia or the tropical regions of the Americas, the family is quite broadly distributed, ranging into southern Europe, the Middle East, and South Africa as well. In general, specimens bear alternating leaves along with monoecious (i.e., separate male and female) flowers, and fill their stems with a toxic sap of milky-white latex. The family is perhaps best known for the raw materials that one of its genera (Hevea) offers to the production of rubber.

Euphorbia, which is named for the ancient Greek physician Euphorbus, is a diverse genus of over 2000 annual and perennial herb, shrub, and tree species for which, historically, humans have found a number of ornamental and medicinal uses. The genus, first described by Linnaeus in the 18th century, occurs mainly in the dryer regions of the tropics and is particularly diverse in Africa. Though different habitat and climate conditions have caused Euphorbia species to undergo divergent evolution, many of these African species find similarly succulent (water-retaining) counterparts in southwestern North America and in Madagascar. The genus's common name, spurge, emerged from the medieval and early modern use of several species' sap as purgatives.

Euphorbia sikkimensis, the plant featured in today's photo, can grow to about 90 centimetres in colonies of herbaceous, mostly unbranched stems arrayed with alternating, conspicuously midribbed leaves of dark green. In the early summer months, the plant crowns itself with a series of bright red buds that later erupt into softly-leveled, star-shaped inflorescences of lime-green and vivid yellow. The species is native to the elevated forests and alpine meadows of southeastern Asia (India, Bhutan, China, Myanmar, Nepal), and its root is commonly put toward medicinal ends. Our plant is sited near the entrance of the David C. Lam Asian Garden, and came to us in 1978 from Hillier Nursery.