Horse Radish Plants
The horse radish belongs to the small company of plants that have given up the habit of producing seed. It is propagated solely by division, and therefore is not subject to improvement by selective breeding. Mr. Burbank once facetiously offered to give a thousand dollars an ounce for horseradish seed. He received many packages of seeds in response to this offer; but none of them produced horseradish plants. Mr. Burbank says the offer is still open, but there is small probability that any one will win the prize, for the horseradish seems to have permanently abandoned the habit of seed production.
This image is from: Luther Burbank: his methods and discoveries and their practical application. Volume 7 Chapter 5