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Related to Hydrorhiza: Hydrocaulus, perisarc


n.1.(Zool.) The rootstock or decumbent stem by which a hydroid is attached to other objects. See Illust. under Hydroidea.
References in periodicals archive ?
caspia is difficult to control because colonies are able to regress, forming menonts, which are small pieces of tissue within the perisarc of either the hydrocauli or hydrorhiza.
Colonies stolonal or erect, up to 19 mm (n = 10) in height, arising directly from creeping hydrorhiza 80-240 [micro]m (n = 10) in diameter.
Colony height did not exceed three millimeters and the hydrorhiza was well developed.