Kagoshima University Research Center for the Pacific Islands, Occasional Papers No.34, 141-144, 2001
Part 2, Section 2, Report 1. The Progress Report of the 1999 Survey of the Research Project“Social Homeostasis of Small Islands in an Island-zone”

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EDIBLE PLANTS AND POISONOUS PLANTS IN MICRONESIA(1) POISONOUS PLANTS IN YAP
Takeomi ETOH

Abstract
Poisonous plants in Yap were surveyed by the literature. In total, there exist 15 poisonous plants
as follows; Barringtonia racemosa Roxb., B. speciosa Forst., Callicarpa cana L., Cassia occidentalis
L., Cycas circinalis L., Derris elliptica Benth., D. melaccensis Prain, Dioscorea bulbifera L., D.
pentaphylla Hook.f., Excoecaria agallocha L., Leucaena glauca Benth., Ormocarpum sennoides DC.,
Pangium edule Reinw., Semecarpus venenosa Volkens and Tacca pinnatifida Forst.
A few of these are very poisonous, and some of the rest are used as fish poison. Besides, there
is a possibility that Laportea interrupta (L.) Chew is poisonous.
Key words: fish poison plant, poisonous plant, YapIntroduction
In Micronesia, there exist many edible plants and also poisonous plants. Unknown origin of
those edible plants in Micronesia, or unknown original habitat of those introduced edible plants,
will be clarified, and they will be classified into endemic and introduced plants. The relationshipbetween the plants in the original habitat and those introduced to Micronesia will be studied, andthe movement of those edible plants will be clarified. The movement of those edible plants must
be related with that of people to Micronesia. Then, clarification of the movement of edible plants
will help us to confirm the ancient movement of people to Micronesia.
Poisonous plants in Yap, Micronesia, and the tropics were already referred by M ERLIN etal. (1996), by K ANEHIRA (1933), and by CORNER & WATANABE (1969), respectively. However,the survey was not sufficient. It is necessary to find out all the poisonous plants and to supply
full information on the poisonous plants to the visitors or travelers and the indigenous people. It
might be necessary to publish a useful illustrated book of those poisonous plants in the tropics
for the safety of people, especially of the visitors. Moreover, it is necessary to study unidentified
poison of those plants. There is a possibility that some useful substances can be extracted fromthose plants. Most of the poisonous plants are well known among the indigenous people.
However, some of the poisonous plants must be unknown to the foreign botanists. The purposeof this research is to collect those poisonous plants in Yap of Micronesia by the literature as afirst step of the research.

Poisonous Plants Including Fish-poison Plants
Barringtonia racemosa Roxb. ; Lecythidaceae (Barringtoniaceae), Common Putat (E; Englishname), Wa’thol (Y; Local name in Yap), Waathul (Y), Sagaribana (J; Japanese name) It is said
that hogs are stupefied by the fruits of this plant (CORNER & W ATANABE, 1969).

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Barringtonia speciosa Forst.= B. asiatica Kurz ; Lecythidaceae (Barringtoniaceae), Sea Putat(E), Biuol (Y), Buiywoll (Y), Goban-no-ashi (J) The seeds of this plant have been used to stupefy fish and octopus in many Pacific islands. To stun fish in tidal pools of the reef, the firm
white seeds can be crushed, mixed with water, and thrown into pools where fish are found. Thismethod does not appear to harm the flesh of the fish as food. The bark is used by some on Yapfor medicine (M ERLIN et al. 1996).
Callicarpa cana L. = C. candicans Burm. f. ; Verbenaceae, Garwew (Y), Kuroshikibu (J),Uotorishikibu (J) The leaves are pounded and then used as a fish-poison. In Yap, the flowers,bark, and leaves are used for medicine, and the fruits are sometimes eaten raw (MERLIN et al.
1996).
Cassia occidentalis L. ; Leguminosae (Fabaceae), Habuso (J) All parts of the plant are poisonous, and this plant has insect-killing ability. The raw seeds or leaves are used as laxative(CORNER & WATANABE, 1969).
Cycas circinalis L. = C. rumphii Miq. ; Cycadaceae, Fal'tiir (Y), Cycad (E), Jawa-sotetu (J)The seeds contain poisonous phytosterin. The starch in the seeds and in the pith of the trunk isedible after washed with water (CORNER & W ATANABE, 1969).
Derris elliptica Benth. ; Leguminosae (Fabaceae), Yuub (Y), Derris (E), Tuba root of Malaya(E), Derisu (J), Toba (J), Haitoba (J), Shirotoba (J) The root contains rotenone, which is theraw material for insecticides against plant pests. The white milky exuded sap from the poundedroots is used as fish-poison, but it is not allowed in many areas because all the fishes are killedwith this. The indigenous people in Malay used this exuded sap from the roots as fish-poison orarrow-poison for hunting. This species is the most widely grown derris (IWASA, 1975).
Derris melaccensis Prain ; Leguminosae (Fabaceae), Yuub (Y), Tachitoba (J) The root contains
rotenone, and this plant is more poisonous than D. elliptica (CORNER & WATANABE, 1969). Thisis used as an insecticide. The roots are pounded and used as a traditional source of poison to stunfish in many tropical areas including Yap. Today, it is against the law for the general public to
use this plant for fish-poison, but people in a few villages can use it because of traditional rights.
Although all parts of the plant may be used in medicine, the roots are not used to make thosekinds of medicine that will be drunk or eaten (M ERLIN et al, 1996).
Dioscorea bulbifera L. v. sativa ; Dioscoreaceae, Rook (Y-south), Yoi (Y-north), Wild yam (E),Bitter yam (E), Air potato (E), Potato yam (E), Aerial yam (E), Kashu-imo (J) The big bulbils
formed at leaf axils and tubers contain dioscorine, which is a weak poison. The bulbils are bitter
when the skin is remained, and therefore, they are used as food after peeled, chopped and boiled
to remove dioscorine. The cooked roots are edible only after grated and washed with plant ash,or after chopped, boiled, and then washed for a few days. Wild plants are not edible (CORNER& W ATANABE, 1969). The round, smooth-skinned, underground tuber can be used in traditional
medicine (M ERLIN et al, 1996).
Dioscorea pentaphylla Hook. f. ; Dioscoreaceae, Doi (Y), Five-leaved yam (E), Goyodokoro (J)Edible Plants and Poisonous Plants in Micronesia (1) Poisonous Plants in Yap

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The tubers contain dioscorine and they are poisonous. The raw tubers are not edible (CORNER &W ATANABE, 1969).
Excoecaria agallocha L. ; Euphorbiaceae, Bat (Y), Bat’nigak’iy (Y), Blind-your-eyes (E),Shimashiraki (J), Metubushi-no-ki (J) The white milky sap exuded from the injured bark is poisonous. The poisonous sap can cause severe inflammation of the eyes, and may leave a person
blind for weeks. Even the smoke of burning wood of this plant is caustic and can cause severe
irritation to the eyes. Fijians sometimes used the bark to treat bad pains caused by the stings ofpoisonous fish (F ALANRUW et al. 1987; M ERLIN et al., 1996).
Leucaena glauca Benth. = L. leucocephala LMK. ; Leguminosae, Ganitnityuwan (Y), Wildtamarind (E), Gingoukan (J) The leaves are poisonous to horses (CORNER & W ATANABE,1969).
Ormocarpum sennoides DC. = O. cochinchinense (Lour.) Merr. ; Leguminosae (Fabaceae),Gaget? (Y), Hama-senna (J) Weak poison (CORNER & W ATANABE, 1969).
Pangium edule Reinw. ; Flacourtiaceae, Rowal (Y), Kupayan (J), Pangi-no-ki (J) This is a famous poisonous plant in Southeast Asia. The plant contains cyanide. The yellow pulp in the fruitcontains cyanide and smells bad rotten onion. It tastes sweet, but it is poisonous when eaten inraw. It is edible after soaked in water for a long time. The cyanide in the seeds is also poisonous.
The seeds are rich in oil and edible after pounded and washed with water. The leaves, resin, andbark are also poisonous, and they are used as fish-poison (N AKAMURA, 1983). The seeds are useful as insecticide, and they are also used to keep or preserve fish (KANEHIRA, 1933).
Semecarpus venenosa Volkens = S. venenosus ; Anacardiaceae, Changad (Y), Doku-urushi (J)The milky sap of the whole plant including leaves is very poisonous and dangerous. Care should
be taken when moving through forested areas that contain trees of this species. Severe skin irritations and rashes can result from contact with the poisonous sap secreted by this plant (M ERLINet al., 1996).
Tacca pinnatifida Forst. = T. leontopetaloides O.Kuntze ; Teccaceae, Chabchab (Y), Polynesianarroeroot (E), East Indian arroeroot (E), Tashiro-imo (J) The poisonous tubers of this plant
yield edible starch if prepared correctly (grated, squeezed, soaked, and allowed to settle beforecooking) (I WASA, 1980; M ERLIN et al. 1996).

Possible Poisonous Plants
Laportea interrupta (L.) Chew ; Urticaceae, Yoyol? (Y) In the same genus of this species, there
exist two poisonous plants ; L. kusaiana in Kusai Is. and L. saipannensis in Saipan Is. These twoplants have white hairs on their leaves. Skin irritations can result from contact with those leaves(K ANEHIRA, 1933). It is necessary to examine whether L. interrupta is poisonous or not.

Literature Cited
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Takeomi ETOHFALANRUW, M.C., WHITESELL, C.D., COLE, T.G., M ACLEAN, C.D. & AMBACHER, A.H. 1987.
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