Marie,
Waimea Falls park is an amazing croton repository. I saw that Ram's Horn and a spectacular clone of Mercer as well. That's where I first saw Monarch, General Marshall and Imelda Marcos (Lemon Top). There are also plants labeled Noblis Major and Davis #17 on the property, near the main house. The groundskeeper at the time was very knowledgeable and said most of the plants were donated by Dr. Brown in the 1980's.