Pinecone or date palm male inflorescence – metaphorical pollination in Assyrian art

The following contribution focuses on Assyrian stone reliefs depicting winged figures holding a bucket and reaching a cone-shaped object toward a stylized tree. Ever since the discovery of the reliefs, the cone-shaped object was considered as either a conifer cone or a date palm male inflorescence used in the symbolic pollination of the stylized tree, derived from the date palm. Utilizing the visual material combined with textual evidence and based on the importance of the date palm as economic resource that gave rise to a plethora of meanings, religious, royal and popular, I shall argue that the scene refers to the artificial pollination of the tree.

Defining the limits of flowers: the challenge of distinguishing between the evolutionary products of simple versus compound strobili

Recent phylogenetic reconstructions suggest that axially condensed flower-like structures evolved iteratively in seed plants from either simple or compound strobili. The simple-strobilus model of flower evolution, widely applied to the angiosperm flower, interprets the inflorescence as a compound strobilus. The conifer cone and the gnetalean ‘flower’ are commonly interpreted as having evolved from a compound strobilus by extreme condensation and (at least in the case of male conifer cones) elimination of some structures present in the presumed ancestral compound strobilus. These two hypotheses have profoundly different implications for reconstructing the evolution of developmental genetic mechanisms in seed plants. If different flower-like structures evolved independently, there should intuitively be little commonality of patterning genes. However, reproductive units of some early-divergent angiosperms, including the extant genus Trithuria (Hydatellaceae) and the extinct genus Archaefructus (Archaefructaceae), apparently combine features considered typical of flowers and inflorescences. We re-evaluate several disparate strands of comparative data to explore whether flower-like structures could have arisen by co-option of flower-expressed patterning genes into independently evolved condensed inflorescences, or vice versa . We discuss the evolution of the inflorescence in both gymnosperms and angiosperms, emphasising the roles of heterotopy in dictating gender expression and heterochrony in permitting internodal compression.