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.
While this plant grows well in high nutrient conditions, it might be that this carnivory can help the plant in low nutrient soils. A study found that
germination was enhanced in low-nutrient soils when nematodes were added. Interesting, but not quite convincing to me yet.
Page citations: Juniper et al. 1989 (and sources
cited therein); Roberts, H.R. et al. 2018; personal observations.
