Didiereaceae.
Didiereaceae are succulent plants from Africa and Madagascar.
The family has 6 genera with 20 species in three subfamilies:
Calyptrothecoideae one genus with 2 species,
Didiereoideae 4 genera with 11 species and
Portulacarioideae with 1 genus, Portulacaria with 7 species.
Didiereoideae.
The succulent plants form thickets of shrubs or trees up to 20 m high.
The thick, spiny stems store water.
Most start with stems trailing on the ground without rooting then become more shrub or tree-like.
Some of the leaves are deciduous.
Most have unisexual flowers in branched clusters.
There are four genera with eleven species.
Distinguishing features between the genera include:
Shrubs can have few or many branches and the shoots can be straight or zigzagged.
The leaves can be round, ovate, lance-shaped or scale-like.
The conical or needle-like spines can be long or short and single, paired or in groups of 4 or more.
Portulacarioideae.
Originally the subfamily was in the Portulacaceae (Purslane) family.
Reflecting this Portulaca fruticosa is a synonym of Portulacaria afra.
Still sometimes seen in Family Portulacaceae the latest studies place the it in the Didiereaceae family.
From southern Africa there are 7 species.
Portulacaria afra will be used to show some of the features of this subfamily.
J.F.
