Rare houseplants are plants that are not commonly found in nurseries or garden centers, and as a result, are considered rare or hard-to-find. These plants can be highly sought after by plant enthusiasts and collectors, as they can add a unique and unusual touch to any indoor plant collection. Human causes of rarity, direct and indirect, are identifiable for many rare plants. The more common are: Loss of habitat, which may already be limited by natural specialization. Loss of pollinators, dispersal agents, or other plant partners.