Orchidaceae is a large family of plants found in temperate-cold to tropical environments and widespread on all continents. Over 25,000 species have been described, distributed in more than 700 genera, but this is an underestimate because new "cryptic" species are still being discovered in tropical forests, which are of extremely small size and live on tree branches (so they are difficult to see). Tropical species are predominantly epiphytic, while species from temperate areas are rooted in the ground. In both cases, however, they have characteristic bilaterally symmetrical, brightly colored and showy flowers. Moreover, these plants have intimate relationships with symbiotic fungi on which they depend from germination onwards. Orchids are famous for their symbolic meaning, are often used as gift plants and represent an important passion for many collectors. They are also plants of great commercial interest; one of the most widely known species, vanilla, is extracted from the beautiful climbing orchid Vanilla planifolia Andrews, which is native to Mexico.
About 53% of orchid species are at risk of extinction (Orchis conservation news, Issue 2, September 2020). Among the causes of disappearance are: habitat destruction in tropical areas to make way for monocultures; the extinction of pollinating insects, since in this group often only one species of insect pollinates a single species of orchid; frequent hybrid creation, especially if carried out in the places of origin, which can result in a reduction in their biodiversity; and finally, the widespread cultivation of exotic species for commercial purposes in tropical countries, which can lead to the replacement of indigenous species in their natural habitats.
Our collection includes various temperate orchid species, cultivated since the 1990s in the area dedicated to geophytes, while in the Fern and Orchid Greenhouse, tropical forms are hosted. There are over 150 specimens in the greenhouse, belonging to 49 genera and 114 species. A small number compared to the total number of known genera and species, just about 0.5% of the total known species, but not negligible for conservation, which is one of the missions of botanical gardens. Such a collection is also an interesting educational opportunity for many aspects related to botany, ecology, and ethology.