This member of the Euphorbiaceae family was described by
Carl Linnaeus in
1753, and later by Hill in 1768 as Tithymalus tuberosus.
It is found on the Cape, South Africa, growing in a well drained soil with some water
and some sun. The swollen stems can grow from two to four
centimetres in diameter, the whole plant up to fifteen centimetres
height. The flowers are greenish yellow.
This might be a winter grower.
Strangely enough, IPNI says:
Distribution: Mexico (Northern America), and author: Joseph Nelson
Rose 1891. I asked them, and got this explanation:
"There are 2 Euphorbia
tuberosa species: Linnaean name (1753) from S. Africa; Rosean
name (1891) from Mexico (a later homonym)."