The analysis of microsporogenesis in Tinantia anomala revealed a unique ring-shaped structure assembling pollen grains into large aggregates. The heterogeneous ring was composed of several segments and was dominated by lipid compounds. Although the ring is a product of the tapetum, such a structure has not been described yet. The authors put forward some hypotheses for elucidation of the role of this structure in the process of male gametophyte formation.
Keywords: Microspore; Microsporogenesis; Pollen grain; Pollen wall; T. anomala; Tapetum.