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 insolation for Christmas Island is very high and the 
neat 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 Pluchea. 
This latter genus is also found around the‘old barracks and buildings in 
the general area. The Pluchea 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 . Cass.ytha .mixing with one or all of: Portulaca , Sida, Boerhaavia, 
Scaevola . Cocos forms a heavy litter. A layer of blue green algae was observ¬ 
ed 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 Keliotropium 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 Hesserschmidtia are 
found along the shore bluff. About one-quarter mile past site M on the left 
one finds the Suriana — Iieliotropium association. On the rise toward the beaoh 
Scaevola is found. Hear the twin antennae installation are large areas 
covered with Lepturus — Sida with Messerschmidtia along the outer shore, 
above the beach. / 
June 17, 19^4 - Motu Upou - Information for vegetation mapping was secured. 
Pour 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 abobe 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. Lep¬ 
turus - Heliotropium ; 2. Iieliotropium - Cassytha - Boerhaavia ; 3. Heliotro - 
pium - Portulaca - Lepturus ; and, 4» Messerschmidtia - Suriana - Heliotropium 
- Cassytha . 
June 18, 1964 - Prom 6 am. to </am. I firmed the stakes placed the previous 
day and took a soil profile sample in the Heliotropium - Cassytha - Leoturus 
stand near the west end of the island just in back of the camp area. He 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 irith 
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 associa¬ 
tion forms a nesting area for many• shearwaters. L. Huber infoms 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 trill provide an area where burrows 
can be made - the vegetationless Leewards were cited as examples. I saw one 
