The diversity of plants in the rainforests of Asia is too much for one page!
Osbeckia lanata. Found in the understory in montane forests in Sri Lanka (Horton Plains, Sri Lanka).
Careya arborea (Jahoo Camp, Cambodia).
Many species in this genus have large red flowers. They are mostly found in the higher altitude forests of Asia.
Rhododendron arboreum, 'Ceylon Rhododendron'. Grows as a shrub in the open or small tree in more protected areas. Leaves greyish-brown on underside due to hairs. Large bunches of a dozen red flowers. Found in cloud forest, endemic to Sri Lanka. (Horton Plains).
Vaccinium leschenaultia, Indian Cranberry. Shrub or small tree. Found in montane forest in India and Sri Lanka. (Horton Plains, Sri Lanka).