C.R. Long 1964 forming a continuous band. The Sesuvium is found on the southeast end alone. The Cassytha is found on Heliotropium and on Suriana but is not as conspicuous on Motu Upou as on Cook island nor does the parasitized vegetation seem in as bad a condition. The Scaevola on Motu Upou seems to have smaller flowers than that observed previously. I think that this particular group of plants is quite distinct from the ones observed and collected on Palmyra. Perhaps the water availability is a key factor. The vegetation resembles the south end of Cook Island although there is less Tribulus and Boerhaavia. Boerhaavia does occur on Motu Upou in dense patches on the inner parts of the island. In the Heliotropium - Lepturus association on the west side of Motu Upou the action of the nesting shearwaters has had the tendency to mound the soil with the plants on top of the mound. June 16, 1964 - L. Huber, F. Sibley and I were forded to the peninsula of Christmas Island which was northeast of Motu Upou. We followed the road east through the Cocos groves and past the airfield to the northeast point. We then continued south along the shore road along the Bay of Wrecks and along the southeast shore to the point where the shore line turns south. I fell behind the others at the northeast point while collecting - later overtaking them and passing as I continued southeast along the road. It was a hot day and the plants wilted fast. In order that I could botanize on the return trip I left at dusk and rode along the Bay of Wrecks after dark sleeping at the roadside from 8 pm. until 3:30 when a shower awakened me. I waited for first light and retraced the previous days route collecting along the way. The long southeast peninsula is interesting and I hope that we will have the opportunity to do a more thorough job in that area. The large land area of Christmas Island makes for a variety of plant associations which were observed along the southeast shore. On the rocky, uplifted sites along the road occur Scaevola - Lepturus and/or Heliotropium associations. The latter species usually occurs in sandy soils where the beach has "blown out" or in wind blow sand pockets in the coral rubble. Along the shore occur stunted or half dead plants of Messerschmidtia. The prevailing wind is from the east and this would seem to be a factor. In the depressed inner part of the island where the wind does not have full desiccating effect the Messerschmidtia grows quite high and has much less dead wood per tree. Large parts of the inner portion of the island are filled with Scaevola, open areas of solid Lepturus, and Lepturus - Sida. The low "lakes" or inner lagoons have rings of vegetation with Sesuvium on the inner side and forming a solid mat on the floor of the depression. On the higher, dry sides one finds seedlings of Portulaca, and then a bare area with a few Lepturus seedlings followed by more solid clumps further back from the edge of the Sesuvium mat. Several score of yards from the edge the Lepturus and Scaevola are mixed and then one finds a solid Scaevola stand. The following associations were observed: 1. Scaevola - Lepturus - Messerschmidtia 2. Messerschmidtia - Heliotropium - Portulaca 3. Lepturus - Sida - Scaevola 4. Lepturus - Portulaca 5. Digitaria - Pimbristylis (Digitaria covering large areas to the east of the road east and south of the airfield.) 6. Sesuvium - Messerschmidtia - Lepturus 7. Lepturus - Suriana - Messerschmidtia - Portulaca 8. Suriana - Heliotropium The controls on the spread of any one species or species association are many: wind protection or not; soil base - from fine coral sand to coarse