Prosotis extends to the Argentine; other characteristic genera are Oenothera, Godetia Collomia, Heliotropium and Eritrichium.
Soc. (1900), lxvi.; Gates, A Study of Reduction in Oenothera rubrinervis, Bot.
Thus in fuchsia and Poinciana, it is red; in Adamia and Tradescantia virginica, blue; in Oenothera and Ranunculus acris, yellow.