Characteristics of multiple-seeded cocklebur: A biotype of common cocklebur (Xanthium strumarium L.)

A new biotype of common cocklebur, called multiple-seeded cocklebur (MSC), was found in Bell County, TX, in 1994. MSC has up to 25 seeds per bur, usua lly producing up to nine seedlings, whereas normal common cocklebur (NCC) h as two seeds per bur which usually produce only one seedling. MSC burs are large, round, covered with hairy spines or prickles, and flattened on one e nd, with each seed terminated by a beak. Leaf morphology differs among the biotypes, and stems of MSC are straighter and smoother than NCC. Apomixis o ccurred with MSC but not with NCC. Both biotypes have potential dormancy wi th germination occurring in the second growing season. MSC produces increas ed numbers of seedlings which increases the difficulty in controlling commo n cocklebur.