A short review of basic definitions relating to the term “tectum” is given. Pollen grains with a tectum perforatum are described and defined. A new term “microreticulate”, is proposed for describing exine structures which consist of minute reticula with thin muri (< 1 μ in breadth) encompassing small lumina (< 1 μ in diameter). The term “reticulate” is to be restricted to reticulate exinessensu stricto.i.e., provided with distinct muri, frequently about 1 μ or more in breadth, and with lumina larger than 1 μ in diameter.