Although elsewhere this fern is found in mountains, in Singapore it grows on our coastal cliffs. In particular, sedimentary rock cliffs which are increasingly rare as we lose them to development.
This beautiful fern was considered common in different parts of Singapore about 65 to 33 years ago, but is now listed as 'Critically Endangered'. In recent history, four of the seven locations where they were found has been lost. Those in Labrador were wiped out in a landslide and have not returned, while those in other locations were lost to development: building of reservoirs, reclamation. Currently, all existing populations are within military areas.
Joseph Lai first saw this fern at Pulau Sarimbun in 2003. We were lucky to have Joseph Lai lead us on a trip to Pulau Sarimbun in 2005 to have a look at them. Dr Chua Ee Kiam posted about the ferns and our trip there on his website.
According to the paper, Dipteris conjugata prefers to grow on 'active cliff environments', i.e., cliffs that tend to collapse in landslides. Though unstable, these habitats provide sufficient light that the plants need. On more stable slopes, they would be shaded out by other beach vegetation.
The paper notes that "it is therefore expected that populations of Dipteris conjugata around Singapore would be relatively transient" and "it is therefore important that active conservation of this species though habitat conservation be carried out".
Read more about the plant in The status and distribution in Singapore of Dipteris conjugata Reinw. (Dipteridaceae). A. F. S. L. Lok, W. F. Ang and H. T. W. Tan. Pp. 339–345. [PDF, 2.55 MB] on the Nature in Singapore site of the Raffles Museum of Biodiversity Research.
More links about Dipteris conjugata
- 'Fossil' ferns found: The discovery of Dipteris conjugata on Pulau Sarimbun, Western Johor Straits, 4 March 2003 by Joseph Lai on his eart-h.com website.
- A curiosity at Labrador by Joseph Lai on his eart-h.com website.
- Pulau Sarimbun by Dr Chua Ee Kiam on his simply green website.
- Dipteris conjugata on the NParks website of the Singapore Red Data Book 2008 (PDF)