Embryo specific (emb) mutants exhibit aberrant embryo development without deleterious effects on endosperm development. We have analyzed five emb mutants of maize, which, based on their developmental profiles can be divided into two groups: mutants arrested at early stages and mutants with novel phenotypes. The members of the first group resemble wild-type proembryos and never reach other developmental stages. In the second group the tube-shaped mutants emb*-8522 and emb*-8535 completely lack apical-basal differentiation, while in mutant emb*-8516 a second embryo-like structure arises from the suspensor. The five emb mutations analyzed are non-allelic and two of the mutations are very likely caused by insertion of the transposon mutator, opening the door for their molecular analysis.