Is horseradish and Wasabi the same thing or are they different, what are the differences in taste and texture, if there are indeed any?
They are different plants -- two different members of the mustard/cabbage family. Both have a similar sharp, pungent flavor and penetrating aroma, but wasabi is generally considered to be more potent. In prepared form, horseradish is somewhat coarsely grated, while wasabi is ground to the finest possible paste. Some (but not all) cultivars of wasabi are green; for others, green coloring is often added during processing.