noun, plural hy·dro·rhi·zae [hahy-druh-rahy-zee] /ˌhaɪ drəˈraɪ zi/.

the rootlike base of a hydroid colony, by which it is attached to the substratum.

Origin of hydrorhiza

From New Latin, dating back to 1860–65; see origin at hydro-1, -rhiza
Related formshy·dro·rhi·zal, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for hydrorhiza

Historical Examples of hydrorhiza