Pollen from false barley (Hordeum murinum, Poaceae).
This pollen type is typical of the grass family - pollen from giant bamboos looks extremely similar to pollen from lawn grass.
Grass pollen starts off as a rough sphere but often becomes folded or crumpled with time.
Technical description of Hordeum murinum pollen, from PalDat (Tweraser & Loos, 2016): medium-sized heteropolar monads, spheroidal or irregular, circular or irregular in polar view, ulcerate/monoporate with annulus, with areolate/microechinate/perforate exine.
In action photo