by Carl Strang
Among the most insidious of our invasive plants are two species of teasels, unfortunate imports from Europe.
One of the studies which caught my eye this past year demonstrated that the other species behaves like a carnivorous plant (Shaw PJA, Shackleton K (2011) Carnivory in the Teasel Dipsacus fullonum — The Effect of Experimental Feeding on Growth and Seed Set. PLoS ONE 6(3): e17935. doi:10.1371/journal.pone.0017935). Dipsacus fullonum, AKA D. sylvestris, the common teasel, has water-holding leaf bases. Shaw and Shackleton experimentally added insects to these little cups, and found that this led to improved seed set and a higher proportion of plant biomass in seeds. Plant growth and total biomass were connected more to rosette size, which in turn is indicative of first season, non-carnivorous growth in this biennial.