Q: What is the genus Capsella like?

• Plant
• Fruit

A: Capsella bursa-pastoris is a European mustard (shepherd's purse) which is now a widespread exotic species in many parts of the world. When moistened, the seeds of this plant release an adhesive compound to which small aquatic animals stick and eventually die. The rotting remains of these bugs may serve as a fertilizer for the germinating seed. This effect is so strong that people have tried scattering them in lakes as mosquito control methods!

Although striking, it is not clear if this really means the plant is carnivorous. There are a few problems with this hypothesis---in particular, this plant does not grow in particularly wet areas, so why should its seed have a carnivorous technique that it cannot exploit? It is more probable that the seed's mucus has other valuable properties we have not yet figured out.

P.S. Can anyone help me find a citation for the use of Capsella bursa-pastoris as a mosquito-control? I can't!

Page citations: Juniper et al. 1989 (and sources cited therein); personal observations.