Orchid mycorrhiza allowed for the identification of specific taxa forming symbiotic relationships which are of interest in the study, cultivation, and conservation of orchids. This is especially important in the trade and preservation endangered species or orchids of commercial value like the vanilla bean. There have been seen trends in the type of symbioses found in orchids, depending primarily on the life-style of the orchid, as the symbiosis is primarily of benefit to the plant. Terrestrial orchids have been found to commonly associate with Tulasnellaceae, however some autotrophic and non-autotrophic orchids do associate with several ectomycorrhizal fungi. Epiphytic fungi, however, may associate
Affine variety algebraic varieties; that is to say, general algebraic varieties such as projective varieties are obtained by gluing affine varieties. Linear structures that are attached to varieties are also (trivially) affine varieties; e.g., tangent spaces, fibers of algebraic vector bundles. An affine variety is, up to an equivalence of categories a special case of an affine scheme, which is precisely the spectrum of a ring. In complex geometry, an affine variety is an analog of a Stein manifold. The most concrete point of view to describe an affine algebraic variety is that it is the set of solutions in an algebraically