A Phaius flower posseses 6 perianth leaves, better said three plus three perianth leaves. The three exterior perianth leaves are called sepals, the three interior ones are called petals. The median leaf of the inner circle of perianth leaves forms the lip and differs significantly from the two other petals. On the lip excrescences like lumps, callices or keels and extensions like a spur can be present. The column is the characteristic feature of an orchid flower, it is found in the centre of the flower. It is a coalescence of all the male and female reproductive organs and is often termed the Gynostemium. Regardless of its absolute and relative size, the reproductive parts are always at its tip. Only one stamen is left in Phaius, in slipper orchids two of them can be found, the distantly related lilies posses three male fertilizing organs. The stamen forms solid pollen-parts, the so called pollinia, in Phaius eight of them can be found.
The pollinia are tough, waxy and precisely delineated structures. The pollinia are held together by a sticky mass, a stipe interpolates itself between the pollinia and the sticky mass. The conglomerate of pollinium, sticky mass and stipe is called pollinaria. Until reaching maturity they are hidden under a structure called anther. The anther will fall off when the pollinaria are removed by a pollinator. The fine structure of the pollinaria provides the most important clues to the group of related species to which an orchid belongs.
The pollinaria are housed at the tip of the column in a cavity called clinandrium. The clinandrium may have a collar-like back wall. The stigma, which is the fertile female part of the flower, is usually located just underneath the clinandrium. A rostellum usually separates the stigma from the pollinarium. The rostellum is part of the stigma and is a kind of roof which prevents the flower from self-pollination. In Phaius it lacks in self-pollinating flowers, for example in Phaius tankervilleae var. antoninae.
If a Phaius flower bud would open normally, the lip of the flower would point upwards (see the flower bud on the left on the pic below). Before the bud opens a rotation of 180 degrees brings the lip in a new position so that the lip points straight to the observer.