Photo above: Earth Fig Ficus megaleia (male fig fruits) growing at Sapulot in Sabah. Earth fig fruits typically grow at ground level on root like stolons that grow from the base of the fig tree trunk. The fig fruits are often covered by leaf litter and may be difficult to find. Photo by Anthea Phillipps.
Earth Fig Leaves typically are very large, soft and slightly hairy with toothed (dentate) edges. Often the base of the leaf is lobed on one side (decurrent) . The leaves of young plants which often grow by the roadside in wet areas are usually much bigger than the leaves of adult trees. The photo above shows the leaves of Ficus uncinata near the entrance to the Kinabalu Mountain Garden at Kinabalu Park HQ.
HOW TO DISTINGUISH THE 8 DIFFERENT EARTH FIGS IN BORNEO
For photos of individual species see the links below
Eight different species of earth figs occur in Borneo in Section SYCOCARPUS. They are all dioecious with separate female and male plants. The two sexes look similar and can only be distinguished by their ripe fruit. Note that only female figs produce seeds and male figs only produce fig wasps.
Earth figs are common in wet forested areas of Borneo, often growing along roadsides. They are distinguished by their very large, often asymmetric, hairy leaves (which are never opposite). To confirm the ID, search at ground level for long root like stolons emerging from the base of the plant with curious dark crimson fruit covered in large bracts.
- F. megaleia:Large dentate leaves with uneven lobed base. 6-24 pairs of side veins not 3-7 pairs (uncinata). Fig has dark crimson glaborous flat bracts which overlap like the scales of a snake not upstanding and hooked like F. uncinata. Unlike Ficus uncinata, F. megaleia only produces figs from stolons on the trunk as an adult, at which stage the leaves shrink in size and become symmetrical. Ficus megaleia, Sapulot, Sabah
- F. geocharis Oblong entire leaves which are symmetrical apart from a very distinctive auricle or “ear” at the leaf base .Ficus geocharis, Kipandi, Crocker Range, Sabah
- F. bukitrayaensis: Large dentate leaves with uneven lobed base. Figs glaborous. Figs with poorly formed bracts. Figs ripen pale pink to white to green.Ficus bukitrayaensis, Tongod, Sabah
- F. stolonifera: Leaf dentate and hairy. Base only slightly uneven. Few bracts on the figs. Soft bright red figs with white spots often on stolons hanging high on the trunk.Ficus stolonifera, Crocker Range, Sabah
- F. subterranea : Leaf entire and symmetrical. Leaf glaborous (not hairy). No auricle. Normal drip tip.Ficus subterranea, Crocker Range, Sabah
- F .beccarii: Leaves entire symmetrical, narrow, with very long drip tips.Ficus beccarii: Introduction
- F. malayana: Leaf dentate with uneven lobed base. Fig densely hairy with hooked bracts.Ficus malayana, Ulu Ulu Resort, Temburong, Brunei
- F. uncinata: Leaf dentate with uneven lobed base. Only 3-7 side veins. Bracts on fig thick and strongly hooked. Figs usually glaborous or only sparse hairs Unlike F. megaleia young plants produce figs. Mature trees develop small symmetrical leaves. Ficus uncinata, Kinabalu Mountain Garden
Taxonomic Notes: The taxonomy of Borneo’s earth figs was originally summarised by Corner in Berg (2005). This treatment was later revised by Berg et al (2007) in A study of the taxonomy of some stoloniferous species of ficus subsection sycocarpus (Moraceae) in Thailand and Malesia.
However it is obvious that the vast variety of the 8 different earth figs found in Borneo do not fit easily into such a rigid framework. In particular;
- It is likely that some earth figs with very large leaves may actually be the juvenile forms of other species (differences in adult and juvenile leaves are very common in the Moraceae plant family) and
- There appear to be intergrades between some species (perhaps hybrids) – particularly F. megaleia, F. uncinata and F. bukitrayensis which all produce very similar large hairy, dentate leaves with asymmetrical bases as juvenile plants. In adult trees the leaves are different again, so the written descriptions given above may not be sufficiently clear cut to identify some individuals.
Ecology: Earth figs are probably dispersed by ground mammals such as rats, porcupines, deer and pigs. The bracts or hairs covering the fig fruits are believed to have evolved to prevent ground birds such as partridges and pheasants from swallowing the figs whole. Toothless ground birds use grit filled gizzards to grind up small seeds and are therefore potential seed predators of earth figs.
The tendency for morphological variation in earth fig leaves and earth fig fruits indicates lower dispersal ability (both of seeds and pollinating fig wasps) compared with bird and bat dispersed figs in Borneo resulting in the genetic drift of relatively isolated earth fig populations. However variations in the DNA of Borneo’s earth fig populations has yet to be studied.
EARTH FIG GLOSSARY:
Asymmetric: Leaf shape is uneven usually with a large lobe on one side at the base of the leaf
Dentate: Toothed edge to leaf
Entire: Smooth edge to leaf
Glaborous: Smooth/shiny with no hairs or sparse hairs
Stolon: Root like “runners” or strings usually produced from the base of the trunk sometimes higher up with figs growing at intervals along the stolon. Stolons may also root to the ground.