Euphorbiaceae

cyathium

 

EUPHORBIACEAE

pronounced: yoo-for-bee-AY-see-uh

the spurge family

 

Euphorbus was a physician in ancient Greece.

This is one of the largest and most diverse of the plant families. Most members exude a milky sap, generally white, and often toxic. There are many herbaceous spurges, but the Euphorbia genus is best known for its many succulent species, some of which appear to be very similar to cacti. All flowers of the Euphorbiaceae are unisexual, and they are often tiny. In the Euphorbia genus, the flowers are reduced even more and are aggregated into an inflorescence known as a cyathium. The main defining feature of the cyathium is the floral envelope (involucre) that surrounds each group of flowers. The involucre almost always has at least one special gland attached, usually on the upper rim, the glands and their appendages varying greatly in both size and shape. There may also be specialized leaves (cyathophylls) surrounding the cyathium. These give an overall floral appearance to the inflorescence. The actual flowers are inside the involucre. There are usually several extremely simplified male flowers – a single anther, filament and pedicel. In the centre there is generally a single female flower – a pedicel and a 3-part ovary, without any petals or sepals.

 

 

 

 

Photograph by Frank Vincentz via Wikimedia Commons