participates_in participates in whole plant gametophyte development stage thallus A whole plant in the gametophytic phase that has a flat growth form and no distinct organs. thalli (exact, plural) PO_GIT:317 PO:0030027 葉状体 (Japanese, exact) rwalls A thallus is a gametophyte of liverworts and pteridophytes and develops from a short-lived protonema. Roughly two dimensional growth results from division of a single apical cell. Thalli may be ribbon or heart shaped or almost filamentous. Although there are no distinct organs, there may be tissue differentiation and dichotomous branching. talo (Spanish, exact) plant_anatomy prothallium (broad) 2011-04-12T08:35:16Z