Ficus diamantiphylla (sect. Ficus ser. Auratae Corner) is described as a new species from Borneo, F. sciaphila (sect. Sycidium Miq. ser. Copiosae Corner) as a new species from New Britain. Both are small pachycaul trees of limited distribution presenting the most primitive vegetative and floral characters in their series. They contrast with the leptocaul species which, with advanced structure, become the common and widespread members of the series. Both species illustrate the manner in which subgeneric evolution, origin and dispersal can be learnt from the pachycaul-leptocaul sequence. F. diamantiphylla places the origin of ser. Auratae in Borneo where the series is mainly endemic. It links with the widespread ser. Eriosyceae Corner, and it is shown how subsect. Eriosycea (Miq.) Corner bears upon the Sino-Himalayan origin of ser. Cariceae Corner with F. carica L. Specific evolution involves the production of new growth-forms and the occupation of new habitats; vicariism plays so little, if any, part that primitive and advanced species live in the same forest. F. sciaphila places the origin of ser. Copiosae, so far as the species with smooth seeds is concerned, in Melanesia in close proximity with ser. Phaeopilosae Corner and ser. Scabrae Miq. It is the pachycaul antecedent to the common and widespread F. copiosa Steud. and F. wassa Roxb.