Maximum likelihood (ML) trees of the bHLH Ia genes constructed based on the nucleotide sequences.

<p>A. The tree was rooted with the Ia genes from <i>Physcomitrella patens</i>; B. The tree was not rooted. Numbers above branches indicate bootstrap values higher than 50%. Ang, angiosperm; Gym, gymnosperm; Smo, <i>Selaginella moellendorffii</i>; Ppa, <i>Physcomitrella patens</i>.