Varieties ending in -maru (-丸)

[bispurious]

This is for the Japanese speakers out there: many varieties of fukiran end in the character 丸, pronounced 'maru'. I know that this character is a common suffix for the name of a ship (i.e. the famous whaling vessel Nisshin Maru, 日新丸), and I was wondering if its use in naming fukiran varieties is related to this meaning. Anyone know for sure?

(Its more usual meaning, circle, is also a possibility, I guess, but I'd say the ship-naming suffix reading is more poetic...)