Chromosome counts of 156 in root tip cells of a bracken plant growing in a natural British population confirm the first record of a triploid in this species. Spore and stomatal measurements support the contention of earlier work that cell size in correlated with ploidy level in ferns, but the plant is unusual in comparison with other odd-numbered polyploids in its degree in its of fertility ('good' spore and functional gametophyte production). Two-dimensional mapping based on isozyme electrophoresis reveal substantial spatial dimensions for the triploid, indicating a plant of considerable antiquity.
No takes yet. Share an insight, caveat, or question.
E. Sheffield (1993) studied this question.