Refers to a local variety of cannabis that was taken from its native land and propagated in another geographic location while maintaining its original genetics. This means that the strain is pure, having never been crossed and always grown in its natural environment. The landrace strains are commonly named after their native regions (ex. Afghani, Thai, Colombian, Hawaiian, etc.) and the traces of these native strains are sometimes detectable in the names of its crossbred progeny.
Merriam-Webster Online Dictionary
heirloom (noun)1.
a piece of property that descends to the heir as an inseparable part of an inheritance of real property
2.
something of special value handed on from one generation to another
3.
a horticultural variety that has survived for several generations usually due to the efforts of private individuals
heritage, traditional, ancestral, original, vintage