How Big is a Bracken Plant?
Horizontal starch gel electrophoresis and isozyme analysis of pinnule extracts proved to be an effective non-destructive method by which to determine the extent of individual plants of Pteridium aquilinum (bracken). Samples from all seven localities studied were found to contain several distinct genotypes, thereby confirming the heterogeneous nature of bracken stands. Individual plants were found to vary considerably in extent, both in Britain and the U.S.A. The maximum dimension measured for the most extensive individual sampled was 390 m. Individuals of this size must represent plants of considerable antiquity. The confident identification of very large plants of a single genotype has implications for control and management trials on bracken, where small plots have often been used.
Sheffield, E., P. G. Wolf and C. H. Haufler. 1989. How big is a bracken plant? Weed Research 29: 455-460.