View photos of the plant Sebastiania bilocularis [Sapium biloculare] Mexican jumping bean.

One of the true ‘Mexican jumping beans’ here: Sebastiania bilocularis (Sapium biloculare). Erroneously referred to as a ‘bean’, the seeds of Sebastiania sometimes become a host for a species of moth larvae, which when developing can cause the seeds to ‘jump’ in the 3-valved capsule.

The pictured exudation of the snipped branch is typical of many Euphorbiaceae, but this species, like others in the family, contains phorbal esters, a group of diterpenoids that are not the friendliest to mammals. In other words, the plant is somewhat toxic…maybe the old ethnobotanical accounts of Mexicans who camped next to the shrub and complained of ‘evil night vapors’, are not that far off.