HISTORY OF TERRESTRIAL VASCULAR PLANTS 



23 



TABLE 3 



Plants Reported from Enewetak Atoll but Found 

 Only as Drift Seeds on Beaches 



Division TRACHEOPHYTA 

 Class ANGIOSPERMAE 



Subclass DICOTYLEDONEAE 

 Family HERNANDIACEAE 



Hernandia sonora L.: St. John, 1960 

 Family FABACEAE 



Caesalpina bonduc (L.) Roxbury: St. John, 1960. 

 Dioclea reflexa Hook, f.: St. John, 1960 

 Entada phaseohides (L.) Merrill: St. John, 1960. 

 Mucuna urens (L.) Medicus: St. John, 1960. 

 Family EUPHORBIACEAE 



Aleurites moluccana (L.) Willdenow: St. John, 1960. 

 Family SAPINDACEAE 



Sapindus saponaria L.; St. John, 1960. 



TABLE 4 



Collection Data of Newly Recorded Terrestrial 

 Vascular Plants from Enewetak* 



Family GRAMINAE 



Lepturus repens (Forst. f.) R. Brown var. subuhtus Fosberg. 

 Enewetak Islet; Mar. 1976; Enjebi Islet: s.n.s.d., coll. by 

 R. Warner (MPRL). 

 Family MUSACEAE 



Musa sapientum L. Enjebi Islet: Planted in Lawrence Livermore 

 Laboratory experimental garden. Japtan Islet: Planted near 

 homes. 

 Not collected. 

 Family ARACEAE 



Epipremnum pinnatuw (L.) Engler cv. "Aureum" Enewetak Islet: 

 Mar. 3 1975, under air conditioner (MPRL). 

 Family AGAVACEAE 



Cordvline terminahs (L.) Kunth. Enewetak Islet: Feb. 12, 1975, 

 near buildings, coll. by E. H. Bryan, Jr. (BPBM). 

 Family RUTACEAE 



Citrus aurantifolia (Christm.) Swingle. Enjebi Islet: Planted in 

 Lawrence Livermore Laboratory experimental garden. 

 Not collected. 

 Family MALVACEAE 



Hibiscus sp. (hybrid, H. rosasinensis x schizopeta/us?). 

 Enewetak Islet: Mar. 1975, near chapel (MPRL). 

 Family APOCYANACEAE 



Plumeria obtusa L. Enewetak Islet: Feb. 1975, near 



buildings (MPRL). 

 Pluweria rubra L. Enewetak Islet: Feb. 1975, near buildings, 

 coll. by E. H. Bryan, Jr. (BPBM). 

 Family VERBENACEAE 



Vitex trifolia L. Enewetak Islet: Feb. 1975, near buildings at 

 southwest end of runway; eilso collected Feb. 12, 1975 by 

 E. H. Bryan, Jr. (MPRL, BPBM). 



"Taxa are listed in the same order as in Tables 1 through 3. 

 Specimens were collected by J. O. Lamberson, 1975 through 

 1977, except as noted, were determined by H. St. John and 

 F. R. Fosberg, and are deposited in the U. S. National Museum 

 Herbarium (USNM), the Bishop Museum Herbarium (BPBM), and 

 the Mid-Pacific Research Laboratory Reference Collection 

 (MPRL). 



the Pteridophyta correlates with that given by Fosberg et 

 al. (1979, 1982). 



Thirty-six species (28.1% of the total) are introduced 

 weeds, and 30 species (23.4%) are introduced ornamentals 

 or food plants. Nineteen of these species occur only under 

 cultivation and are considered transient members of the 

 flora (Table 2). Seven species (5.5%) have been reported 

 only as drift seeds found on beaches (Table 3). New 

 records for the atoll reported in this chapter (Table 4) 

 bring the total number of species recorded from the atoll 

 to 128. 



Enewetak Atoll averages 125 to 150 cm of rain annu- 

 ally and is much drier than atolls farther south, which are 

 closer to the tropical convergence zone just north of the 

 equator. Observations during the period 1975 to 1977 

 and meteorological records show that there is a definite 

 seasonality on Enewetak: dry and windy from November 

 through April, with more rain and less wind the other half 

 of the year. 



The plants of Enewetak reflect this seasonality, produc- 

 ing more flowers and fruit in summer and shedding some 

 or most of their leaves in winter, depsending on the 

 species. Pisonia forests become open and light in the 

 winter because Pisonia trees shed most of their leaves. 

 This species flowered abundantly in January and February 



1976, and the flowers were followed by the sticky fruits 

 and new growth of leaves in March and April. Terminalia 

 trees shed almost all of their leaves, which turn yellow and 

 drop in the dry season. Cordia, Tournefortia, Guettarda, 

 and Scaevola shed some of their leaves during the dry sea- 

 son and produce more flowers and fruit during the summer 

 months. Premna and Hibiscus tiliaceus shed many of their 

 leaves in winter, and new growth is produced in April or 

 May. Pemphis, Suriana, Cocos, and Morinda produce 

 flowers and fruit year round, though the plants may 

 appear more wind-blown and dry in winter, and the seeds 

 usually germinate in early summer. 



Many of the ground plants and weedy species also 

 reflect the seasonality. Annuals such as Con\/za, Physa/is, 

 and some of the grasses are seen mostly in summer, as 

 are Laportea and Portulaca. Ipomoea species are present 

 year round but flower in summer. Tacca dies down in 

 October or November and grows from the underground 

 tubers in April or May, producing flowers in June and 

 seeds in July. Ci^perus species flower in summer, although 

 Fimbristy/us is in bloom year round. Euphorbia sp>ecies arc 

 present year round, but Phxjlhnthus is much more 

 abundant in summer. Waltheria also dies down in winter, 

 and new growth is seen in April or May. 



Tropical storms, though uncommon in the Marshall 

 Islands, do occasionally occur in the vicinity of Enewetak, 

 and storm waves sometimes wash over the islands. The 

 dense shrub growth at the top of most of the island 

 beaches affords some protection to plants farther inland, 

 but storms may wash away parts of the islands or damage 

 the larger trees, esp)ecially Pisonia, which is soft and easily 

 broken. A typhoon approached the atoll in the summer of 



1977, causing some damage to the Pisonia on the leeward 



