Rounding Up Resistance: Weed sacrifices seeds to put up with a herbicide

Use of a common agricultural herbicide is driving evolution of at least one weed species, a new study finds. In response to applications containing glyphosate, the tall morning glory (Ipomoea purpurea) grows increasingly impervious to that chemical, while sacrificing a measure of its fertility.

GLORY IN RESISTANCE. The tall morning glory, a tough weed on farms, may evolve tolerance to a herbicide but pays a price in the number of seeds it produces.