Root like structures called rhizoids are present. In funaria root like structures called Rhizoids are present. Sporangiophores arise among distinctive, root-like rhizoids. Protonema is a combination of chloronema, caulonema and rhizoids. Ribbed bog moss anchors to the substrate with rhizoids. They are typically anchored to the littoral substrate by means of branching underground rhizoids. Lichen physically weather rocks by penetrating the rock's small crevasses with their rhizoids. "R. oryzae" has abundant, root-shaped rhizoids. Both nuclei migrate out of the zoosporangium and into the conjoined rhizoids where they fuse. There are many long rhizoids on the underside of the thallus but no ventral scales. This thallus is often extensive, infecting many host cells, with highly branched, fine rhizoids. In the last group, rhizoids of compatible strains meet and fuse. The underside is covered by many root-like rhizoids which attach the plant to the soil. They are attached by rhizoids or haptera to a rocky surface or other alga. Thalli are coenocytic and usually form no true mycelium (having rhizoids instead).