In a corymbose manner; in the manner of or with the structure of a corymb.
From corymbose plus -ly adverbial suffix, creating an adverb form rarely used in botanical writing because plants don't really 'act' in adverbial ways, but preserved in technical literature.
Corymbosely is a ghost word—technically grammatical but almost never used because you don't usually describe verbs or actions in botanical writing. It's like a grammatically perfect sentence that almost never gets written. These orphan words tell us about the logical limits of language-building systems.
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