Excoecaria agallocha

Excoecaria agallocha View in CoL ( Euphorbiaceae ) was common in the Islands and found to inhabit the landward edges of mangrove forests along with terrestrial vegetation.

Lythraceae

Lythraceae View in CoL sensu lato was represented by four species from the genus Sonneratia viz ., Sonneratia alba View in CoL , Sonneratia caseolaris View in CoL , Sonneratia griffithi , and Sonneratia ovata View in CoL , of which only S. alba View in CoL was reported by all the reviewed literature. While Parkinson (1923) had reported S. alba View in CoL as a species with restricted distribution at Betapur of Middle Andaman, it was found to be commonly distributed in all the regions across various habitats, either alone (Burmanallah and Shoal Bay of South Andaman) or together with stands of Avicennia View in CoL and Rhizophora View in CoL (Dugong Creek of Little Andaman) in our surveys. Further, the Sonneratia species reported as Sonneratia acida View in CoL (actually S. caseolaris View in CoL ) by Parkinson (1923) had white petals in contrast to their characteristic dark red petals. Nehru and Balasubramanian (2011) reported S. caseolaris View in CoL from four re-colonizing mangrove habitats viz ., Kamorta, Katchall, Nancowrie, and Trinket of Nicobar Islands, although the corresponding photograph (figure 3D, p 255) in the article suggests that S. alba View in CoL has been misidentified as S. caseolaris View in CoL for the following reasons: 1) mucro with no re-curved point, 2) white staminal filaments, 3) dull pericarp, and 4) cup-shaped hypanthium. Sonneratia apetala View in CoL has not been recorded during the present study, although it has previously been reported from the Islands by several authors ( Table 3). A few trees of Sonneratia griffithi were observed at Betapur (Middle Andaman) during our surveys, as recorded by Ragavan et al. (2013). Subsequent et al. (2009) at Burmanallah (South Andaman) was conto the new record of S. ovata View in CoL from Radhanagar of Havelock firmed to be a variegated form of B. gymnorrhiza during in the Andaman group of Islands ( Dam Roy et al. 2009, our surveys. As B. gymnorrhiza and B. sexangula View in CoL are mor- Goutham-Bharathi et al. 2012) and from tsunami-impacted phologically similar, the number of colleters (finger-like mangrove habitats of the Nicobar Islands (Nehru and Bal- glandular structures inside the base of stipules) could be asubramanian 2012), our surveys revealed its presence at a useful diagnostic character ( Sheue et al. 2005). Wandoor (South Andaman), thus, indicating that regional Although two species of Ceriops viz ., Ceriops tagal View in CoL and endemics may have a wider distribution in the Islands. Ceriops decandra View in CoL have previously been reported from the Islands, only the former was found in the present study.

Dagar et al. (1991) reported C. decandra View in CoL from Chidiyatapu

Meliaceae View in CoL (South Andaman) two decades ago as a very rare species. Dagar and Singh (1999), Debnath (2004), and Yao et al.

Tomlinson (1986) recognized three species of Xylocar- (2011) have also reported C. decandra View in CoL from the Andaman pus ( Meliaceae View in CoL ) viz ., Xylocarpus granatum View in CoL , Xylocarpus View in CoL and Nicobar Islands but without giving a description or meckongensis (= Xylocarpus gangeticus View in CoL ), and Xylocarpus View in CoL locality data.

moluccensis View in CoL on the basis of habitat, trunk, fruit size, Of the four previously reported Rhizophora species, and root elaboration, of which only the former two are only three viz ., Rhizophora apiculata View in CoL , Rhizophora mucroregarded as true mangrove species. Parkinson (1934), too, nata, and Rhizophora stylosa View in CoL were found in our studies. recognized three different species of Xylocarpus View in CoL and high- Identification of mangrove hybrids is problematic (Duke lighted the problems in differentiating X. granatum View in CoL from et al. 2002). Singh et al. (1987b) was the first to record X. meckongensis . However, there is a great deal of ambi- Rhizophora lamarkii (a sterile hybrid between R. stylosa View in CoL guity in Xylocarpus species due to deficient taxonomic x R. apiculata View in CoL ) from Havelock amidst R. apiculata View in CoL and descriptions ( Tomlinson 1986, Jayatissa et al. 2002). Two R. mucronata View in CoL stands ( Table 2). It was subsequently species of Xylocarpus viz ., X. granatum View in CoL and X. moluccensis View in CoL added to the mangrove flora by several authors ( Table 3). (= X. gangeticus View in CoL and X. meckongensis ), were found in our However, our present study revealed the presence of Rhizsurveys. Of these, the former was commonly distributed, ophora hybrids at Havelock (South Andaman) and Kimious whereas the latter was rare and found only at Baratang Bay (Car Nicobar), which stresses the importance of periof Middle Andaman. However, X. moluccensis View in CoL was also odic surveys in mangrove stands where parental species observed at Havelock (South Andaman) and at Karmatang of Rhizophora View in CoL taxa typically co-occur ( Duke 2007) as there of Mayabunder (North Andaman) by the investigating are major taxonomic problems with Rhizophora View in CoL (Duke et al. team during a pre-tsunami period (2003). 1998) despite its ubiquitous occurrence throughout the tropical world ( Tomlinson 1986, Duke et al. 2002). Further,

it is important to note that hybrids of Rhizophora View in CoL were pre-

Myrsinaceae viously reported by Ragavan et al. (2011) from Havelock. The inclusion of Kandelia candel in the mangrove

One species representing Myrsinaceae , Aegiceras cornicu- flora of the Islands by several authors ( Table 3) could not latum, was commonly encountered in our surveys. be explained as it has not been observed since Brandis (1907).

Rhizophoraceae

Three species of the genus Bruguiera viz ., Bruguiera cylindrica , Bruguiera gymnorrhiza , and Bruguiera parviflora were reported in our surveys, among which B. gymnorrhiza was found to be the most common in the middle and upper intertidal zones. Singh et al. (1987b) were the first to record Bruguiera sexangula in the Andaman and Nicobar Islands, and it was reported in all subsequent studies. However, it was not encountered during our surveys across the Islands. It is important to note that the Bruguiera species reported as B. sexangula by Dam Roy

Rubiaceae