Theories about the seed scale of conifers are reviewed. The classical Foliar Nature theory

of Delpino & Penzig suggested that the ovuliferous scales in pine are homologous to the foliar ap-

pendages of a cone axis. The Ligular theory of Sachs & Eichler maintained that the seed scale of co-

nifers is comparative to a ligule, because it grows out from a foliar organ, namely the bract. Bessey

thought that the seed scale of conifers is the combined outgrowths of an ovule from its chalazal end,

which is a sui generis structure thereafter. Kubart misproposed the aril nature of the ovuliferous

structure in Juniperus. Arber‘ s Partial-Shoot theory held that an ovuliferous scale is homologous to a simple and limited shoot (a partial shoot) based on the Telome theory, but Meeuse remarked that

the Telome theory was abused here. Dupler emphasized the integumental nature of the ovuliferous

scales in taxads. The Brachyblast theory of Braun has increasingly convinced the present botanists on

account of excellent studies from teratology, anatomy, ontogeny and palaeobotany. Based on the es-

tablished evidence from teratology, anatomy, ontogeny and palaeobotany, the present authors believe

that the seed scales of living conifers may have evolved from the secondary reproductive branches of

the early conifers by phylogenetic metamorphism and fusion, and little differentiation during ontoge-