platanaceæ

from The Century Dictionary.

• An order of apetalous trees of the series Unisexuales, consisting of the genus Platanus, and characterized by having monœcious flowers in dense globose heads, without calyx, and with but few or minute bracts, by the ovary with one cell and one ovule, and the fruit a ball of numerous long achenes, each narrowed iuto a slender base surrounded with long hairs. See cut under plane-tree.