Floristic value of Nee Soon swamp 
61 
Table 4. Number of species and tree species (> 5 cm DBH) from the vegetation plots in each 
national conservation status (natives) or invasive status (non-natives). 
Category 
No. of species 
No. of tree species 
Native 
660 
285 
Not threatened 
120 
50 
Vulnerable 
144 
55 
Endangered 
111 
53 
Crit. End. 
232 
106 
Not assessed 
—Previously presumed Extinct 
38 
13 
—New records 
13 
8 
—Others 
2 
0 
Exotic 
8 
3 
Cultivated only 
1 
0 
Casual 
4 
2 
Naturalised 
3 
1 
Cryptogenic Weed 
3 
0 
Total 
671 
288 
Discussion 
The Nee Soon catchment harbours 53 presumed Nationally Extinct species according 
to the most recent Singapore Red Data Book, as well as 11 species records and two 
varieties which are new to or had been overlooked in previous checklists of the 
Singapore flora (e.g., Chong et al., 2009). Our findings reinforce published opinions 
(e.g., Turner et al., 1994; Turner et al., 1996a) that the Nee Soon Swamp Forest merits 
the highest conservation priority in Singapore, and is of comparable floristic value to 
the more well-known Bukit Timah Nature Reserve. 
It does not necessarily follow that one should automatically confer upon 
rediscovered species the status of Critically Endangered. One example is Uvaria 
curtisii, which has been collected from multiple localities in the nature reserves in 
recent years. Another example from previous rediscoveries is Grenacheria amentacea 
(C.B.Clarke) Mez, which appears to be fairly widespread in Nee Soon (Table 3) and also 
in the part of the Central Catchment Nature Reserve along Mandai Road (K. Y. Chong, 
personal observations). It is likely that these species belong to poorly documented 
