The South African Boneseed, Chrysanthemoides monilifera, is one of our worst environmental weeds. It was introduced to the You Yangs to control erosion and has spread widely, invading a variety of habitats locally.Plants can live up to 20 years and, at maturity, can be producing up to 50,000 seeds yearly which can lie dormant for 15 years.
Boneseed seedling
I decided to do a mathematical exercise, modelling the course of an infestation over 20 years. I started with one plant just germinating in Year One. In Year Two, it produced 10 seeds, in Year Three, 20 and so on to Year 10 when it produced 90 seeds, then died. As you can see from the numbers, these are very conservative figures, especially as many seeds are eaten by birds and rats, some do not germinate, overcrowding may limit plant density. But anyway, how do the numbers progress?
Have a guess and CLICK here to find the answer.
Neil Tucker