Key genes controlling, gametophyte, embryo, sporophyte, rhizoid and stomata development in bryophytes. Bottom: Phylogenetic relationships of the major lineages of land plants illustrating the monophyly of bryophytes, lycophytes, ferns, gymnosperms and angiosperms (tracheophytes) (Li et al., 2020). CLE, refers to the number of CLE signalling peptide encoding genes. Kn: Klebsormidium nitens, Aa: Anthoceros agrestis, Mp: Marchantia polymorpha, Pp: Physcomitrella patens, Sm: Selaginella moellendorffii, Af: Azolla filiculoides, Pa: Picea abies and At: Arabidopsis thaliana. Numbers in yellow boxes indicate the number of homologs in the corresponding species genome. Purple boxes with “x” indicate the absence of the homolog (Miwa et al., 2009; Bowman et al., 2017; Li et al., 2018; Whitewoods et al., 2018; Zhang et al., 2020; Li et al., 2020; Nystedt et al., 2013) .