Cacalia in America: from Arnoglossum to Yermo. Taxa from the United States previously assigned to Cacalia, because of their shared character of generally creamy-white flowers, can be better placed in four genera: Argnoglossum, Hasteola, Psacalium, and Rugelia. In addition, the recently described genus Yermo belongs somewhere in this polyphyletic grouping, probably nearest Arnoglossum, even though it has bright-yellow flowers. Arnoglossum is the largest stirctly American genus, with eight species; Hasteola has two (some Asian species have been assigned here but do not belong), whereas Rugelia and Yermo are monotypic. Psacalium is a Mexican- centered genus with about 40 species, but only one enters the United States (in southern Arizona). The group is heterogeneous; nearly every genus has a distinctive chromosome number. Hasteola does not even belong to the same subtribe of Senecioneae as the others.

Key words: Arnoglossum, Hasteola, Yermo