Classic MIKC-type MADS-box genes (MIKC(c)) play diverse and crucial roles in angiosperm development, the most studied and best understood of which is the specification of floral organ identities. To shed light on how the flower evolved, phylogenetic and functional analyses of genes involved in its ontogeny, such as the MIKC(c) genes, must be undertaken in as broad a selection as possible of plants with disparate ancestries. Since little is known about the functions of these genes in non-seed plants, we investigated the developmental roles of a subset of the MIKC(c) genes present in the moss, Physcomitrella patens, which is positioned informatively near the base of the land plant evolutionary tree. We observed that transgenic lines possessing an antisense copy of a MIKC(c) gene characteristically displayed knocked-down expression of the corresponding native MIKC(c) gene as well as multiple diverse phenotypic alterations to the haploid gametophytic and diploid sporophytic generations of the life cycle. In this addendum, we re-examine our findings in the light of recent pertinent literature and provide additional data concerning the effects of simultaneously knocking out multiple MIKC(c) genes in this moss.