Polyporate grains
Earth History Research Center

The polyoprate forms (sometimes called periporate) characterize a large number of very common families such as Chenopodiaceae, Amaranthaceae, Convolvulaceae, Cucurbitaceae and many others. Because of the similarities between these forms, they are often classed together and "Cheno-Ams" during counting. A careful analysis of the surface features and diameters and number of pores can help work out the taxonomy with more precision.

The grain shown here on the left in two focal planes demonstrates well the "golf ball" aspect of the polyporate grains. In the middle is a grain from the prickly pear cactus (Opuntia), and on the left is a grain from the small mallow genus, Sida. Both these latter grains have been reduced in size relative to the Chenopodium on the left. Note particularly that the cactus grain is smooth, and the mallow grain is spiny.