Euphorbiaceae, Cnidoscolus chayamansa, chaya
Chaya can be maintained as a medium- size shrub, or a small tree. If managed properly and left to grow big I can imagine it could become quite large. When damaged or broken the leaves and branches exude a caustic white sap containing cyanide. If the sap comes in contact with your body it will burn. The Chaya leaves can be boiled for five or ten minutes to be eaten. cooked leaves have an excellent flavor and contain high levels of nutrients. Tender, young leaves have a superior flavor then the larger, more fibrous ones. In addition to the leaf the young branch tips can be boiled and eaten, their flavor reminiscent of Asparagus.
Chaya is most common in Mecixo where it is eaten as a cooked green and used to wrap tamales, it was an important food in pre-Colombian times.
Chaya may occasionally flower (see photo below) but I have never seen it produce a fruit or seed. I have had luck propagating it from large cuttings, planted directly in the field. During the right time of month, younger tip cuttings take. Cuttings tend to be slow to get started but once the plant is established it grows fast and can be harvested frequently.
The plant needs no water during a four month dry season, very drought tolerant. Likes full sun but will grow fine in part shade.
Chaya is a fantastic addition to any tropical agroforestry systems or homegardens. As the leaves and branches are large and thick it makes for an fantastic, long-lasting, fibrous mulch. The plant/tree can be copiced heavily and will sprout back quickly. Young leaves and growing tips are of superior quality for eating.
There are numerous species of chaya. I have seen another one, perhaps a less edible more medicinal varitey the leaves resembling those of a papaya tree.. There are other species with small hairs on the leaves. The species depicted in the above photo is the most desirable edible species of chaya that I know of.