Common ragweed (2n=36), giant ragweed (2n = 24), and their reciprocal F1 hybrids (2n = 30) were analyzed for a number of traits. Hybrids of the type giant ragweed♀ × common ragweed♂ were obtained via immature embryo culture. The analyses revealed a surprising contribution of the pollen parent for features such as biomass, leaf area, and specific leaf area. Leaf morphology, however, was similar to the maternal parent. One plant, originating from crosses of the type common ragweed♀ × giant ragweed♂, developed abnormally and cytological analysis revealed the presence of 24 chromosomes in its somatic cells. Probably this plant had an androgenetic origin.
