Chromosome Studies in Subtribe Melittidinae (Labiatae) and Systematic Implications

Chromosome numbers are documented for the first time for Brazoria, Macbridea, and Synandra. The latter two have 2n = 18. Brazoria comprises two cytologically distinct subgroups: 1) B. scutellarioides, with 2n = 20 plus one to four small bodies interpreted as supernumerary chro- mosomes, and 2) B. arenaria, B. pulcherrima, and B. truncata, with 2n = 28 and lacking supernumer- ary chromosomes. Chromosomal data corroborate morphologically circumscribed subgroups within Brazoria and provide weak support for a relationship between Macbridea and Synandra.