About 100 species of mostly fast growing evergreen or deciduous shrubs, occasionally small trees, some are subshrubs or only herbaceous. Stems usually 4-sided. Leaves usually opposite, but B. alternifolia is alternate, lanceolate to ovate, short petioled. Flowers in long clusters and fruit a 2 valved capsule with many numerous, small seeds. About 100 species, mostly tropical or subtropical and evergreen, especially in East Asia; only B. globosa is native to South America.
Some authorities say that Linnaeus spelled the genus as Buddleja, and this is the way name appears in his Species Plantarum, published in 1753, in which the genus was first described. However, others argue that this "j"-spellng was the work of typesetters who used j's for i's, just as they used v's for u's. Jeff Gillman (Univ. of Minnesota) points out that in printed indexes of these early texts the alternate spellings were rarely used by typesetters. Unfortunately Species Plantarum does not contain an index. However, in Linnaeus' 1797 work on plant systematics, Systema vegetabilvm, Buddleia is spelled with an "i" in the index. So Gillman concludes that this is the spelling Linnaeus intended. Some current botanical references are adopting the "original 1753 spelling" (Gillman would call it the "original misspelling"). The ITIS (Integrated Taxonomic Information System) lists Buddleja as the accepted name. It is likely that nurseries and horticultural publications in the U.S. will continue to spell the genus as Buddleia.
Buddleia: after the Rev. Adam Buddle (1660-1715), an amateur English botanist.