ABOVE: Illustration of Ficus fistulosa (as Covellia subopposita) from Choix Pl. Buitenzorg (1864) illustrating a plant from Java. Note that the basal veins are very variable often one sided (uneven) and the angle from the midrib matches that of the other side veins. This is in contrast to F. variegata in which the basal veins are matched, straight and prominent and join the midrib at a smaller angle. This is true of both the adult and the juvenile leaves.
FICUS FISTULOSA Reinw. ex Blume (1825) SECTION: SYCOCARPUS
Latin: fistulosus =hollow, referring to the hollow young twigs. See photo above;
Habit: Large shrub to small twisted tree to 18 m, one of the most common secondary forest figs often found growing along riverbanks or streams. Also often along forested roads in urban areas.
Leaf: Large 8-22 cm (but up to 34 cm) long by 4-9 cm wide with pale veins. Young leaves sometimes flush pink. Normally 6-10 pairs of side veins. The leaves are very variable and young leaves are dentate (with saw teeth) similar to the young leaves of Ficus variegata.
Fig: The medium sized figs (1-3 cm) grow in bunches on the trunk (cauliferous) and individually along the branches (ramiflorus). The figs occasionally grow on stubby branchlets as in the photo above although this is more characteristic of Ficus rosulata. Figs ripen greenish yellow and are dispersed primarily by small Cynopterus fruit bats and also by palm civets.
The inner surface of female figs ripen bright scarlet to purple. This is also characteristic of Ficus tengerensis.
Male figs may ripen pale yellow to almost white and are larger than female figs. Both male and female figs attract ants of at least two species which feed on both pollinating (beneficial) and parasitic fig wasps. As with all male figs these rot on the tree or fall uneaten to the ground. At Bidanu, Brunei Plantain Squirrels gnawed open ripe make figs so that they could eat the emerging fig wasps.
Similar species and their differences
(1) F. variegata. Figs may ripen green, pink or red. Trunk is very tall, straight and white with large buttresses not short and twisted. With both species the figs grow in bunches on the trunk (cauliferous) and branches (ramiflorus).
(2) F. septica. Similar sized small tree also common in urban areas. Leaves have prominent white veins. Figs are clearly ridged longitudinally and are heavily marked with dots. The fig colour tends to be grayish green not bright green.
(3) F. lepicarpa: Leaves very similar but usually 8-12 pairs of side veins not 6-10 pairs. Figs often have brown scurfy markings. Figs always have an “equator line” around the fig and usually one or two flat bracts on the side of the fig fruit. Figs grow in the leaf axils not cauliferous
(4) F. rosulata: Very similar but has a prominent cone shaped peak of black bracts around the ostiole. Fig colour varies from brown to green.
(5) F. satterthwatei Very similar but has bracts or ridges on the side of the fig.
Note that Berg & Corner (2005) and Berg (2011) describe two additional varieties of F. fistulosa which also occur in Borneo (a) With figs that ripen reddish (rare in Borneo) and (b) F. fistulosa variety tengerensis (normally 4-6 pairs of side veins).
On this website F. tengerensis is regarded as a separate species.
Distribution: Abundant in most areas of Borneo up to 2,000 m, including urban areas such as Bukit Padang and Signal Hill in Kota Kinabalu.
Range: NE. India east to Taiwan, south to Java and east to New Guinea. A common fig of secondary forest, parks and gardens in Singapore.
ECOLOGY: In Singapore fruiting was “big bang” with up to 5 crops (female) and 7 crops (male) per tree per annum, but with no synchrony between individual trees. Some female trees were never without figs. Most female figs were taken and eaten by small Cynopterus fruit bats when still hard and green. Male figs turned yellow and dropped uneaten to the ground at wasp exit time. (Corlett 1987)