De Vries and Ie (1970) noted that male sterility did not necessarily affect orbicule
Pollen, tapetum and orbicule
development in Modiolastrum malvifolium (Malvaceae).
surface ornamentation often resembles that of the pollen sexine (Rowley et al.
The images were transferred to an image-processing software (Macnification, Orbicule
Two possibilities are FailSafe from Phoenix Technologies for PCs and Undercover from Orbicule
types can be described in Rubiaceae (Huysmans et al.
2000) found that the tribes Coffeeae, Octotropideae, Ixoreae, and Pavetteae are characterized by specific orbicule
It has been reported that  orbicules
originate in the cytoplasm of the tapetal cells as lipoidal pro-orbicular bodies that accumulate below the membrane and eventually extrude to the cell surface (facing the locule) where they provide sporopollenin precursors for exine formation.
in Angiosperms: morphology, function, distribution, and relation with tapetum types.
Palynology is the science that studies contemporary and fossil palynomorphs, including pollen, spores, orbicules
, dinoflagellate cysts, acritarchs, chitinozoans and scolecodonts, together with particulate organic matter (POM) found in sedimentary rocks and sediments (Jansonius and McGregor 1996).
The circular patterns in this piece of ijolite are called orbicules
--circular or ovoid structures that grow in concentric shells around a central core.