FIGURE 1. Cumulative number of named biserial, non-pinnate fenestrate genera by decade from the first genus named in 1838. The arrows indicate decades of relatively rapid proliferation of generic names; several genera characterized by superstructures (red) were named during the 1880s, and during the 1970s several genera that lack superstructures (green) were named. The curves reflect all validly published generic names, whether or not they are widely accepted as well founded, or are generally considered to be junior synonyms.