FIGURE 2 in ×Polascontria (Cactaceae), a nothogenus that represents the gene flow between Escontria and Polaskia

FIGURE 2. Pollen micromorphology of Polaskia chichipe, Escontria chiotilla and hybrids. A, D, G and J: E. chiotilla; B, E, H and K: hybrids; C, F, I and L: P. chichipe. A. Seeds of E. chiotilla (oval, black-brown and rugose seeds with smaller cells toward hilum forming a spanded border as those of hybrids). B‒C. Seeds of P. chichipe (oval, black-brown, but ruminate, with interstices cratered, the cells close hilum are smaller and form a spanded border around it). D. Cuticle of seeds in E. chiotilla [striate as in hybrids (E, top), although some hybrids produce some seeds with irregular striations on seed coat, specially forming cuticles thickness extended and hardly visible between cells walls, mainly on lateral regions (E, bottom)]. F. Cuticle in P. chichipe (striate). Pollen grains in E. chiotilla (G), hybrids (H, upper) and P. chichipe (I) (spheroidal, radiosymetric and tricolpate). The exine in all taxa is tectate, perforate and spinulose (J−L). The aperture membrane is granular (K). The hybrids produce several non-viable pollen grains that are empty and collapsed (H, in the bottom). Scales are: A, B and C=500 μm; D, E (in the top) and F=100 μm, E (in the bottom) =10 μm; G, H (in the top and in the bottom) and I= 10 μm; J, K and L= 1μm.