A marrow seedlings self-sown in my garden when I turned it over; so I just let them grow. The plant became pretty large and had typical marrow shaped leaves. The female flowers started to produce perfectly round, and bright yellow fruits. I had a pumpkin out front the year before for halloween, and thought that maybe a seed somehow got into the garden. I was surprised when they matured into round marrows that look very pumpkin like. I cut one open just to make sure it was a marrow. This marrow is 36 inches around and weighs around 20-25 pounds (using fish scale).