umbellet

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A secondary umbel in a compound umbel, as in the carrot. Also called umbellule.

Century Dictionary and Cyclopedia

1. n. A little or partial umbel; an umbel formed at the end of one of the primary rays of a compound umbel; an umbellule. See cut under Osmorrhiza.

Wiktionary

1. n. a secondary umbel in a compound umbel such as the carrot; an umbellule

GNU Webster's 1913

1. n. (Bot.) A small or partial umbel; an umbellule.