image
FIG. 22.13 Speciation by hybridization. In sunflowers, Helianthus anomalus (bottom) is the product of natural hybridization between H. annuus (top left) and H. petiolaris (top right).
Source: (top left) Gary A. Monroe @ USDA-NRCS PLANTS Database, (top right) Jason Rick, (bottom) Gerald J. Seiler, USDA-ARS.