Euphorbia

The Euphorbia genus comprises more than 2000 species of annual and perennial herbs, shrubs, trees and weedy plants, making it one of the largest flowering plant genera on earth. Almost all the species contain a milky latex that is often caustic and warned against. Many of the species are succulent. It takes a little getting used to realising that the garden poinsettia and the Karoo vingerpol belong in the same genus.

The leaves are alternate or opposite, often reduced and short-lived in succulent species. There may be stipules that are sometimes spinescent in the succulent species.

More euphorbias are monoecious than dioecious, i.e. more bear their male and female flowers on the same plant. The cyathia or pseudo-flowers are axillary or terminal, cup-shaped structures with nectar glands around the rim, alternating with lobes. Several small male flowers surround a female flower when monoecious, otherwise occurring in separate cyathia. Sepals and petals are usually absent or rudimentary in Euphorbia.

Cyathia grow solitary or in two to several cymes, umbels, panicles or clusters. Male flowers are mostly only single stamens. Female flowers are sessile or short-stalked ovaries consisting of several locules, each bearing a pendulous ovule and usually three variously shaped styles. The smallness of the cyathia makes use of a magnifying glass advisable for effective inspection and study.

The fruit is a fleshy capsule consisting of two-valved carpels, maturing into a woody structure. The seeds have smooth or sculpted surfaces, sometimes with fleshy attachments, called caruncles.

The photo shows some imposing tree euphorbias in Limpopo, probably Euphorbia cooperi (Leistner, (Ed.), 2000; Frandsen, 2017; Smith, et al, 2017; Wikipedia).