The Orchidoideae, or the orchidoid orchids, are a subfamily of the orchid family (Orchidaceae). They typically contain the orchids with a single (monandrous), fertile anther which is erect and basitonic. The subfamily Orchidoideae and the previously recognized subfamily Spiranthoideae are considered the closest allies in the natural group of the monandrous orchids because of * a shared terrestrial habit * sectile (capable of being severed) or granular pollinia * erect anthers. The Orchidoideae contain two subclades with the following tribes : * Habenariinae * Orchidinae