The TCP family of putative transcriptional factors, defined by the founding members Teosinte branched1, Cycloidea and PCF, is characterised by a specific basic helix-loop-helix domain. CYC and PCF subfamilies have been defined on the basis of sequence differences in conserved domains. Twenty-four coding sequences containing a TCP domain were found in the complete genome of Arabidopsis thaliana using BLAST searches. A neighbour-joining analysis of 112 sequences from various angiosperm taxa, belonging to the TCP family, suggests (i) homoplasy for the presence/absence of an R domain, (ii) multiple independent duplications leading to the wide diversity of CYC subfamily sequences in the five plant families sampled.