(1975) and Walker and Walker (1984) showed that it lacked columellae below the reticulum but was otherwise angiosperm-like, with a normal sulcus rather than a proximal monolete scar, supratectal spinules on the reticulum, and a thick nexine made up of foot layer around most of the grain, plus endexine below the sulcus, as in Chloranthaceae and fossil pollen identified as Clavatipollenites.
Pollen adhering to the carpels and found in isolated stamens from Portugal (Friis et al., 2006, 2010) has supratectal spinules, a sculptured sulcus, and a thick nexine made up of foot layer, plus endexine under the sulcus, as in Ascarina, Clavatipollenites, Hedyosmum, and Asteropollis.
The exine is 2.80 m thick and the ectexine is thicker than the endexine. Intine thickness is 0.54 m.
The exine is 2.52 m thick and the ectexine is thicker than the endexine. Intine thickness is 0.51 m.
Endexine was reticulated, and ectexine was intectate.
According to Saenz de Rivas (1976), exine is composed by endexine, which is an internal reticulated layer, and by an external gemmate layer called ectexine that shows a striate without tectum.
The exine has a very thin endexine
layer, and a fibrilar intine with numerous invaginations coated by the plasmalemma can be observed.
4), pollen endexine
thickening, and operculum of pollen absent (Chen & Zhang, 1991; Zhu et al., 2014a, b).
data) reflecting the process of endexine
development in the same species (El-Ghazaly et al., 2001).
layer differs from the endexine
in having fewer lipids and more proteins
The systematic value of endexine
ornamentation in some Psychotrieae pollen (Rubiaceae-Rubioideae).