Note on Induction of Flowering in Xanthium

Abstract
An aqueous extract of floral primordia of the palm Washingtonia filifera was applied to vegetative plants of X. canadense, a strict short-day type. Such extracts, given through a flap of stem, induced floral initiation in 58 of 68 treated plants. The activity was heat-stable. Further extracts made from other specimens of W. filifera from other spp. were ineffective.