By Allison Kubo Hutchison
A scientific study of orchids revealed why they were so difficult to cultivate: they lacked an important aspect of the orchid habitat. Many species of orchids rely on a complex symbiosis with mushrooms to propagate their seeds and thrive in the wild. These mushrooms, commonly called orchid mycorrhiza, specialize in each type of orchid and are often only found in association with their preferred species of orchid. During the seed stage, these reciprocal mushrooms inhabit and feed the seed, which has not evolved to have nutrient stores of its own. The symbiosis of the two organisms continues over the life cycle of the orchids, and different fungi, each orchid having a variety of cooperating species, feed the plants on phosphorus, nitrogen and carbon. When the fungal networks break down, the plants can even ingest them through their roots. As the orchid ages, the complexity and biodiversity of the fungi with which it works increases. Given the immense biodiversity of orchids, orchid mycorrhizas make up about 10% of the total botanical biodiversity on earth.
In 1902, Lewis Knudson, a botanist at Cornell University, introduced a method of cultivating orchids that mimicked the environment created by the symbiotic fungus. With agar gel or some other rich nutrient solution, the small seeds were able to grow in an extremely hygienic environment. With the ability to grow from seeds, gardeners have created 100,000 unique hybrid orchids, which has also brought the price down significantly. Orchid growing is a tedious process, and it takes years for the beautiful variety of grocery stores to grow from tiny seeds to Mother’s Day gifts.
Photo credit: Illustration by Sarah Ann Drake from Sertum orchidaceum: A Wreath of the Most Beautiful Orchid Flowers (1838), selected by John Lindley.