A genus of probably only two species in temperate E. Asia, closely allied to Schizophragma and perhaps to be included in it. Apart from the immaterial difference that the species of Pileostegia are evergreen against deciduous in Schizophragma, there is really nothing to separate the two genera except that in the latter some flowers are sterile and bear large showy sepals, whereas in Pileostegia all the sepals are normal. But as Dr Stapf pointed out in the article accompanying Bot. Mag., t. 9262, some species included without question in Hydrangea lack the showy ray-flowers shown by the majority of the species (e.g. H. hirta and H. serratifolia). If the presence or absence of this character in Hydrangea is not considered to be of generic value, it is scarcely justifiable to use it to separate Pileostegia from Schizophragma. Dr Stapf accordingly transferred P. viburnoides to Schizophragma, which was the first of the two genera to be described.