C.R. Long 1964 coral rubble, or, hardpan soils; standing water - salt or fresh; salt spray; enclosed lakes or "lagoonlets"; rainfall; insolation and reradiation of light energy. The insulation for Christmas Island is very high and the heat accumulation over the large land area is great despite the prevailing winds. There were showers every late afternoon and early evening of our stay on the island. On the northeast part of the island where the Cocos plantations are being extended many bare areas are being drained. Under the Cocos trees one finds Lepturus and where the shade is not dense Plucheas. This latter genus is also found around the old barracks and buildings in the general area. The Plucheas grows to a height of 10 feet. The Suriana - Messerschmidtia stands which are found most commonly around the shores of the lagoon have abundant litter. In some areas one finds no clearly defined associations with most of the herbaceous species being present. In one area the following species were observed growing in the same area: Lepturus, Heliotropium, Cassytha, mixing with one or all of: Portulaca, Sida, Boerhaavia, Scaevola. Cocos forms a heavy litter. A layer of blue green algae was observed about one-quarter of an inch below the soil surface. On the bare areas surrounding the lagoon - composed of surfaces just an inch or two above the high tide waters - I think that Sesuvium and Lepturus are first colonists with Suriana following. Digitaria is commonly found on the northeast shore with Heliotropium and Scaevola. Past the Site Y cutoff Lepturus is found in a solid stand. The Scaevola is found in protected sites. If not, the plants are wind damaged and very compact in growth. On the sand hills across from the site M on the east side are Lepturus and Sida (in bloom). On the west side of the road are Scaevola and Messerschmidtia. Scattered Messerschmidtia are found along the shore bluff. About one-quarter mile past site M on the left one finds the Suriana - Heliotropium association. On the rise toward the beach Scaevola is found. Near the twin antennae installation are large areas covered with Lepturus - Sida with Messerschmidtia along the outer shore, above the beach. June 17, 1964 - Motu Upou - Information for vegetation mapping was secured. Four permanent markers were placed on this Motu: 1. fifty paces southwest along old water pipe line from the ne. shore; 2. thirty-seven paces due south of the mid point on the northeast shore; 3. as above but ninety paces further south; 4. forty paces south of the northeast shore toward the east point. All of these markers are at least 41 in. above the soil surface and were sprayed green in color. The following associations are represented: 1. Lepturus - Heliotropium; 2. Heliotropium - Cassytha - Boerhaavia; 3. Heliotropium - Portulaca - Lepturus; and, 4. Messerschmidtia - Suriana - Heliotropium - Cassytha. June 18, 1964 - From 6 am. to 9 am. I firmed the stakes placed the previous day and took a soil profile sample in the Heliotropium - Cassytha - Lepturus stand near the west end of the island just in back of the camp area. We then prepared our gear for Motu Tabu which is almost due south of Motu Upou. After setting up a tentless camp we set out to work over the island. The soils on Motu Tabu are based on sand - the top layers are whitish, the underlayer with moisture drawn up from the sea level lens beneath the island. This layer is light brown in color. The Phoenix Island petrels often make a semicircular depression at the base of a Lepturus clump. The Cassytha - Heliotrope association forms a nesting area for many shearwaters. L. Huber informs me that the wedgetailed shearwaters may burrow in abre sand if enough depth is present thus vegetation is not needed for the formation of certain soil types which favor burrowing. Thus an open sandy islet will provide an area where burrows can be made - the vegetationless Leewards were cited as examples. I saw one