Pollen Analysis Circular The last issue of the "Pollen and Spore Circular" (#18) was edited by Calvin J. Heusser and announced the fusion, indicating that "the spore and pollen section will constitute four to six pages in each issue and contain essentially the same material" as in the "Pollen and Spore Circular". The final issue also included abstracts from the First Palynology Conference (February 25, 1953), held at Yale University as well as correspondence from researchers working as far afield as Düsseldorf, Lucknow, and Indianapolis. It was in the pages of the "Pollen Analysis Circular" that the field of pollen analysis was given
Annulus (botany) dissolve to allow the cap to fall off and the spores to be released. Annulus (botany) An annulus in botany is an arc or a ring of specialized cells on the sporangium. These cells are arranged in a single row, and are associated with the release or dispersal of spores. In leptosporangiate ferns, the annulus located on the outer rim of the sporangium and serves in spore dispersal. It consists typically of a ring or belt of dead water-filled cells with differentially thickened cell walls that stretches about two-thirds around each sporangium in leptosporangiate ferns. The thinner walls on the