These are Spurges, of which the botanical name, Euphorbia derives from Euphorbos, the Greek physician of king Iuba (or Juba) II of Numidia (52–50 BC – 23 AD), who married the daughter of Anthony and Cleopatra and used the plant as a powerful laxative.
Euphorbias range from tiny annual plants to large and long-lived trees. The genus has over or about 2,000 members, making it one of the largest genera of flowering plants. Several of them, as picture above, can be found in our forest:
Euphorbia lathyris, rare but easy to recognize.
The plants share the feature of having a poisonous, milky, white latex-like sap, and unusual and unique kind of floral structures called a cyathium, where each flower in the head is reduced to its barest essential part needed for sexual reproduction.
More to be seen on:http://jeantosti.com/Fleurs/euphorbe.htm