patchily distributed. Rare to locally abundant, percentage 

 cover from less than 1% in herb mats of tiny motus to 60% in 

 tall Pisonia forest. Best represented on Nake, Long, Brothers, 

 South, Pisonia, Eitei, and Mannikiba, where coverage exceeded 

 50% in appropriate habitats. To 1.1 m tall on Kimoa. 



Ecology : Largest specimens found under Tournefortia. 

 Pisonia, Cocos, or Pandanus. Tiny (1-2 cm) and tougher in 

 sunny, exposed sites. Halophytic, pioneering in herb mats on 

 islets less than 0.75 ha in size (e.g., Fishball). Optimum habitat 

 is Tournefortia scrub, in sunny clearings, or belts behind beach 

 scrub. Uncommon in Pisonia forest. Occurs in both windward 

 and leeward sites, but in greater density leeward. Will persist 

 through several stages of plant succession if given adequate 

 shade. 



Phenology : Flowers and fruit in October. March, and 

 May. 



Substrata : Primarily beach gravel or coarse rubble. Also 

 rubble-sand mixtures; not lagoon silt. 



OLACACEAE 



* (#?) Ximenia americana L. (Fig. 1 1 ) 



Never previously collected. K-90-170 South Island. 

 50-100 m north of cistern, elevation 0.3 m. 10-20 m from 

 coastal Tournefortia fringe, within Cocos plantation. Collected 

 by crew of the yacht Amanita and posted by Anne Falconer to 

 AKK. 



Distribution and Abundance : Locally abundant in one 

 location, about 50 bushes ( 3—4 m high, 2-3 m wide ) spread over 

 about 100 m. Adjacent to indigenous scrub, on edge of Cocos 

 plantation near old settlement. 



Phenology : Flowering in July 1990. 



AMARANTHACEAE 



* Achyranthes canescens R. Br. (Fig. 16, PI. 41 ) 



Never previously collected. K-88-1 South Island, 

 Tr. 5, to 0.7 m, elevation 0.3 m, in Tournefortia fringe, coral 

 rubble. 



Distribution and Abundance : Quite widespread, primarily 

 in interior scrub and forest of 19 motus (Table 3), from tiny, 

 barely vegetated Fishball (0.73 ha) to the largest. South 

 (1 06 ha). Density variable: from less than 1 % in Tournefortia 

 scrub to 50% local ground cover in mixed Pandanus forest. 

 Primarily associated with Tournefortia. May be locally abundant 

 in clearings in Pisonia forests, pure or mixed. Often in a zone 

 dividing Tournefortia and Pisonia trees, especially on Pig, 

 Brothers, and Nake. 



Ecology : Never in natural herb mats. Needs shade but 

 requires some direct sun: rare in pure stands of Cocos and 

 Pisonia. Prefers small, sunny openings in forest or scrub. 

 Drought-resistent and probably partly halophytic. Dies back 

 annually in the dry season and reappears with winter rains 

 (Anne Falconer, personal communication). To 1.5 m tall. 

 Little or no capacity for dispersal by sea. On other islands, 

 seeds carried by birds, especially fruit pigeons (Guppy, 1906), 



but pigeons are absent from the Line Islands. Perhaps dispersed 

 by the long-tailed cuckoo (Ellis et al., 1990). 



Phenology : Flowers and fruit present in October, March, 

 and May. 



Substrata : Lushest growth in humus soils of forest interiors. 

 Often grows in pure rubble. 



NYCTAGINACEAE 



* Boerhavia repens L. (Fig. 17, PI. 34) 



Boerhavia diffusa L. 



Boerhavia hirsuta: Sensu Bennett, 1840 



Boerhavia species: Dixon. 1884 



Formerly Known Distribution : Reported 1 840, collected 

 1 884; L-32 1 0. 3324, 3239, 3225, 3252, 3262, 3289, 329 1 from 

 Windward, Tridacna, Nake. Long, Emerald, and South, 

 respectively. 



Present Distribution : Cosmopolitan, widespread in the 

 Pacific. K-90-164and 165 from Ana- Ana. Range extension on 

 Caroline from 6 to 33 motus (Table 3). 



Abundance : Present in every habitat, leeward and 

 windward, ranging from less than 1 to 80% cover. Often in 

 unpredictable patches. Best locations (>50% cover) on Nake, 

 Long, Windward. Pig, Brothers, Arundel. Tridacna. South. 

 Ana-Ana, Pisonia. and Pandanus Islets. 



Ecology : Mostly found beneath Tournefortia. either in 

 pure scrub or mixed with Pisonia. Cordia. Morinda. Suriana, 

 or Cocos. Not in deep Pisonia shade; rarely in herb mats. Thick 

 ground cover in indigenous scrub ( Shark ) or within clearings in 

 old Cocos-Ipomoea forest (South), where it mingles with 

 Phymatosorus, reaching a high density (PI. 34) and large size 

 (rooting at nodes, vines exceeded 1 mlong). BIRDS: Bristle- 

 thighed curlews fed within the Boerhavia mat in old Cocos 

 forests. South. Sticky seeds (.32 cm [one-eighth inch] long) 

 found entangled in preened down and adhering to contour 

 feathers of a juvenile great frigatebird (PI. 42). Species is 

 customarily dispersed around large oceanic areas and within 

 atolls by seabirds such as red-footed boobies (Guppy. 1906; 

 Ridley. 1930). 



Phenology : Small mauve flowers and seeds present in 

 October, March, and May. 



Substrata : Coral rubble with sand or humus, rarely pure 

 beach rubble. Lushest growth in humus-and-guano-laden 

 rubble clearings where Pisonia forest once grew. 



* Pisonia grandis R. Br. (Fig. 18; PI. 43) 



Formerly Known Distribution : Collected 1884; L-3280 

 4 m tree, north shore. South. Small grove, north end. Long. 



Present Distribution : Cosmopolitan, pan-Pacific. Caroline 

 range extension from 2 to 29 motus (Table 3). 



Abundance : A major plant community (see Plant 

 Communities section). Caroline^ Pisonia forests, some of the 

 last remaining groves in the Pacific, are of special conservation 

 value. 



Substrata : Occupies, and contributes to. best soils on atoll: 

 mixture of rubble, humus, and guano. 



18 



