blechnum ferns, first vegetals after volcanic eruption, piton de

ferns fern pioneer vegetal vegetation piton fournaise volcanic volcano reunion france rock ripple move circular shape pattern details fronds desolate desolation lines lava flow flows molten ripples folds pahoehoe wrinkles viscous basalt basaltic blechnum tabulare lomariocycas tabularis mountain cracks crevice ropy vegetals eruption