Plate 23. Morphological features of palynomorphs [larger image]
380 Annulus and Operculum 381 Os and Vestibulum 382 Diagram of aspidate grain showing os, pore, vestibulum, nexine, and sexine 383 Exine: Nexine and Sexine 384 Lophate pollen and lacuna 385 Equatorial view of tricolporate pollen with lalongate pore	386 Diagram of colporate pollen grain showing pore dimensions (h = pore height; w = pore width) 387 Reticulate sculpture: Lumen and Murus 388 Monolete spore with perisporium 389 Polar view of tricolpate grain showing polar area 390 Polar view of syncolporate pollen and apolcolpial field 391 Ulcus