The plant Tolmiea menziesii is the only member of the monotypic genus Tolmiea. It is known by the common names youth on age, thousand mothers, and piggyback plant. It is a perennial plant commonly kept as an ornamental. It is native to the west coast of North America, especially in regions dominated by redwoods. It requires moisture and does not tolerate much sun or dry conditions.
The plant is most interesting for its reproductive habits. It grows plantlets from the petiole near the base of each leaf. The plantlets drop off, fall in the soil, and take root there. It will also reproduce by rhizome and by seed propagation. It bears small flowers of various colors, usually brownish-purple to white depending on the cultivar. It has hairy, toothed leaves and a capsule fruit containing spiny seed.
The plant is also unusual in that it is sometimes diploid and sometimes tetraploid, due to autopolyploidy.
The genus was named after the Scottish-Canadian botanist William Fraser Tolmie.