So, it's a castor bean. I finally found out that's the volunteer plant in our porch pot -- one missed by the renegade flying car.
It's a fascinating plant. Related to the Mexican jumping bean and, like coffee, not technically a bean, it is one of Southern California's native species. And its Latin name suggests its danger: ricinus communis -- it's got ricin in it, the deadly poison. Its name suggests that its beans, described by some as "beautiful," look like engorged ticks.
The seed pods on my plant haven't popped yet. So what should I do?
According to W.P. Armstrong in his wonderful Bio 101 web page "Wayne's Word" from Palomar College, "The spiny seed pod or capsule is composed of three sections or carpels which split apart at maturity. Each section (carpel) contains a single seed, and as the carpel dries and splits open, the seed is often ejected with considerable force. Walking among large castor shrubs on a hot summer day can be quite an experience, with the sound of exploding carpels and seeds flying through the air and bouncing off road signs, sidewalks, and your head.
"Although castor oil is rather malodorous and distasteful," Armstrong continues, "it is the source of several synthetic flower scents and fruit flavors (esters), such as jasmine, apricot, peach, plum, rose, banana, and lemon. The chemicals (esters) responsible for these flavors and aromas are obtained from ricinoleic acid, one of the important ingredients of natural castor oil. In fact, ricinoleic acid comprises about 90% of the total triglyceride fatty acids of castor oil. Castor oil is also used in making soap, inks, and plastics; for preserving leather; as an illuminant; in Turkey red oil for dyeing and finishing textiles; and in brake fluids and certain insecticidal oils. Even after the oil has been removed, the poisonous crushed seeds or oil cake (pomace) makes an excellent fertilizer.
"Brazil and India are two of the major world producers of castor oil," Armstrong writes, "although the plants are grown commercially in many other countries, including the United States (New Mexico, Texas, and the midwestern United States). It has been estimated that the world production of castor seeds was nearly one million tons in 1970. In terms of total production, castor oil is one of the world's most important industrial vegetable oils."