Ficus deltoidea growing in a hothouse at the Royal Botanic Gardens Edinburgh in July 2016. From herbarium collections Ficus deltoidea is Borneo’s most common fig but because it grows mainly in the canopy and on the summits of high hills and  mountains it is rarely encountered by casual visitors.
Ficus deltoidea leaves can be recognized  by the  distinctive black glands on the underside of the leaf. These glands  produce a waxy secretion intended for consumption by ants that protect the tree against leaf eating insects such as butterfly and moth caterpillars.
Ficus deltoidea leaves also have distinctive glands on the upper side of the leaf. These glands are called hydathodes and are used by many plants to excrete waste water containing dissolved minerals.
Ficus deltoidea. Note the active hydathodes on the upper surface of this fig leaf as well as the three “ant” glands at the base of the leaf blade.
Ficus deltoidea. This is the under surface of the leaf shown above with multiple ant glands.


Visitors to the Flora Malesiana 10 Conference held at the Royal Botanic Gardens Edinburgh in July 2016 admiring a Ficus deltoidea growing in one of RBG hothouses.