Long Persistence and Other Aspects of Variants of False Mayweed, Tripleurospermum maritima, at Sackville, New Brunswick

Résumé

Over a 25-year period, plants of Tripleurospermum maritima with aberrant inflorescences have been observed growing without cultivation by Crescent Street in Sackville, New Brunswick. Aberrant plants varied between years in locations, suggesting reproduction by seed. Plants with variant inflorescences comprised about one percent of total plants in counted samples. As many as 100 variant plants were found in a year. The site may have received toxic waste disposal causing a mutation that resulted in observed aberrations. The inflorescence aberrations are primarily of two kinds; those with only white rays throughout, and those with some yellow disc flowers that later were concealed by white rays. A third aberration involved inflorescences that appeared nearly normal when first seen, but later developed to the second preceding form. Plants with aberrant inflorescences did not differ from normal plants in morphology or flowering time. Aberrant inflorescences appeared somewhat later in the flowering period than flowering in plants with normal inflorescences.