Arctostaphylos tomentosa arc·tos·tap·hylostomentosa uncommon noun 1. erect openly branched California shrub whose twigs are woolly when young Synonymsdowny manzanitawoolly manzanitaArctostaphylos tomentosa Related words Broader terms manzanita WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.