Flower Gallery / Orchid. Orchid is one of the most successful and adaptable family of plants. Some orchids which prefer a more acidic condition, will encourage ants to live on them, even in some instances creating suitable chambers for their guests to live in, and in addition to warding off their enemies, the ants increase the acidity on the plant through their own use of formic acid as a defense system. The orchid in this picture is a cymbidium orchid.