The present invention relates to isolated nucleic acid molecules and their corresponding encoded polypeptides able confer the trait of modulated plant size, vegetative growth, organ number, plant architecture and/or biomass in plants. The present invention further relates to the use of these nucleic acid molecules and polypeptides in making transgenic plants, plant cells, plant materials or seeds of a plant having plant size, vegetative growth, organ number, plant architecture and/or biomass that are altered with respect to wild type plants grown under similar conditions