Stamen of vegetable marrow with pollen grains. These grains are slightly smaller than pollen of common hollyhock, and have similar shape (sphere with small spikes), but on these grains we can see also bigger spikes. For comparison, here is electronic microscopy image of marrow pollen grain:
Gear: my usual “snowflake” macro setup (i described it in article about snowflake macro photography). Daylight from left side, no diffusor, no reflector. Averaged stack of 64 identical shots.
Looks better in original resolution: 800 * 800 pixels.