NAT. HIST. BULL. SIAM Soc. 38 : 117 ・133 ， 1990 TAXONOMY ，ECOLOGY AND CONSERVATION OF RAFFLESIA KERRII MEIJER IN SOUTHERN THAILAND Willem Willem Meije r* and Stephen Ellio tt** ABSTRACT Rafflesia Rafflesia kerrii Meijer ，Th ailand's largest flower ，is described from buds exam ・ ined ined at Khao Sok National Park ，Surat Th ani Province ，southem Th ailand ， in greater detail 由加 previously 陀 ported. Current knowledge of the distribution ，s凶 us and ecology of 白E species species is reviewed. 百官'eats to 白e survival of R. kerrii include habitat destruction and ove ト collection collection by local villagers for medicinal purposes and other reasons. R. kerri i' s status is vulnerable ，according to IUCN Red Data Book criteria. We suggest 出at R. kerrii should be promoted promoted as a tourist attraction ，in conjunction with a well planned education program ，to provide provide an economic incentive for local people to protect 白e species. We also suggest that the the govemment enact legislation to protect Th ailand's botanical treasures ，including R. ker- rii ，from commercial exploitation. INTRODUCTION The flowers of R a_ 伊esia kerrii Meijer (R afflesiaceae) (in 官 lai "bua poot" or "bua toom 勺訂'e undoubtedly the largest ， most magnificent and most bizarre in Th ailand ，reach- ing ing a diameter of 70 cm or more (Fig. 1). Yet ，despite its obvious attractions ， very little is is known of this extraordinary plan t. It was not even in cI uded in the revision of the Raf- flesiaceae flesiaceae in Flora of Thailand (HANSEN ， 1972). This is surprising as the species may be endemic endemic to Th ailand and could become a major tourist attraction ， if adequate steps are taken taken to conserve both the species itself and the habitat where it grows. Li ke all members of the Rafflesiaceae ， R. kerrii is a parasite ，possessing no roots or or green leaves of its own. For most of the year it exists as microscopic filaments and plates plates of tissue growing inside the roots of a host plant ，usually a li 加 a in evergreen fores t. From time to time however ，it develops buds which burst through the bark of the host's roots ，grow to about the size of a football and eventually open to become one of the largest flowers flowers in the world. For a short time ， the foul smelling flowers a町 act insects ， which are thought thought to carry out po Ili nation ， but within a few days of opening ， the flowers shrivel and tum into a black ，putrescent mass. The seeds of this species have not yet been found. R. R. kerrii was first coll 配 ted by Dr. A. F.G. Kerr ，Th ailand's first govemment bota- nist ， in 1927 and 1929 from 4 locations in Southem Thailand (Fig. 17) (JACOBS ， 1962). 集 T.H. Morgan School of Biological Sciences ，Th omas Hunt Morgan Building ，Univer 冨ity of Kentucky ， Le xington 40506 ・0225 ，U.S .A. 料De partment of Biology ，Faculty of Science ，Chiang Mai University ， τ'h ailand 50002. 117 117 118 118 WILLEM MEUER AND S百四聞ELLI O'IT τ'h e most recent published report of the species w 錨 pt:O vided by N 町 OMDHAM & KUBAT (1 987) who photogr ョphed an open flower at Kh long Nakha Wildlife Sanc 伽釘y，Ranong Pr ovince ， in March 1987. In In an earlier paper (MEuE R ，1984) ， the seniof au 血 or identified R. kerrii as closely related related to ， but distinct 合OID ， R. cantleyi Solms- La ubach which occ 町 s in the Malay Pen- insula. 百首 s asse 凶on was based on examination of herbarium specimens and a phoωgraph of 佃 open flower made by Kerr held at the Kew herbarium. However ， because the speci- mens were cut into 白泊 slices and not pre 田 :rved 鎚 whole flowers in alcohol ，some fea 加res could could not be de 闘 rnined with complete acc 町 acy. Th e observations presented here come from examination of fresh buds at Kh ao Sok National Park and 白ey help 加 cαnple 飽白e description description of the species. We reaffmn the view that R. kerrii is a distinct species ， but now suggest 白紙 it is not as closely related to R. cantleyi 錨 previously thought. We also discuss conservation conservation m 回 S町 es which may be necessary to save 血e sp 回 ies 企'om extinction. DESCRIPTION In In March 1989 ，血 e junior au 血or visited Kha o Sok National P 紅 k (8 ・54'-9 ・08' N ，98 ・28'-98 ・ 46'E) Surat Th ani Pro vince ，southern 官凶land ， to search for R. kerrii. No living living specimens were found in the vicinity of the national p釘 k headquarters ， but the species species w 踊 commonly collec 削 by local people fi 町 medil 伽 al purposes. Th e pho 旬伊:p hs and and description below therefore come from several 1釘 ge buds (T able 1) obtained from local local villagers ，who unfortunately had recently cut them 合国n the hos t. R. kerrii flowers m 壱 unisexual. One female bud grew on 血e same host root 槌 several males ， but it is not known whether this indicates a single mon 田 cious R. kerrii individual or several dioecious Table Table 1. Details of Rafflesia kerrii Meijer buds examined at 貼 ao Sok National Park. Sex Bud diame 加「 Cupula No.of No.of (cm) (cm) diameter Pr ocesses An thers (cm) (cm) M 25 14 36 28 M 21 11 41 30 F 18 11 42 M 16 8 27 26 M 44* 31* *From the dried central disk of a male flower kept 錨 a curio by a local villager. RAFFLES/A KERR/1 MEIJER IN SOUTHERN THAILAND I 19 Peri gone Lobe Di aphragm Host Root 20 cm Fi gure I . An open flower of Rajjlesia kerrii Meijer. Processes Scale Central Di sk Peri gone Lobe Anther -----, Diaphragm Collar of Di sk Ramentae Annulus Peri gone Tube Sul cus Column Annulus Cupul a 10 cm L.---- Root of Host Liana Figure 2. Longtituclinal sec tion through a male bud of R. kerrii. 120 WJLLEM MEJJ ER AN D STEPJ-J EN ELLJO'IT 3 4 Figure 3. A young R. kerrii bud, just emerging through the root bark of the host li ana. Figure 4. Two R. kerrii buds. The left one is still enclosed by scales. but the scales of the right one have parted slightl y. exposing the pink under surface of the perogone lobes. The white ruler in thi s and subsequent figures is 15 cm long. RAFFLE S/A KERR II ME IJ ER IN SOUTHERN THA IL AND 12 1 5 6 ~~圃園田園圃圃園田園...::!ーーーー-ーーー 7 ー『司圃 品噌 E 困 ー=置 --司 Figure Figure 5. U nd er sur face of diaphra gm. T hro ll gh th e ce ntral op 巴nin g of th e diaphragm ，th e upp er sllrf ace of of th e peri go n巴 lob 巴S ca n be see n. Figur e 6. C lose- lI p of lI PP 巴r surf: 日ce of perigon e l obes showi ng wh it e m arg in ，s m all warts and shall ow depr ess ion s Figur e 7. C lose- up of un der surf ace of diaph ragm showmg transition from white dot s to ramentae. 122 WJLLEM MEJJER AND STEPI-IEN ELLIO'IT 8 9 Figure 8. Bonom ha lf of ma le R. /.:errii bud showing central disk and proce sses . Figure 9. Close-up of processes, showing slightly darkened tips. RAFFLESJA KERRJJ 勘fE UER 町 SOUTHERN THAILAND 123 ones. ones. Except when stated otherwise ， measurements are for the largest bud examined (a male ，25 cm in diameter). Technical terms for bud and f1 0wer p訂 ts are indicated in Figures 1 and 2. In itially ， buds develop beneath the bark of the roots of the host liana. Th e rl ∞t bark bark appears to expand and thicken as the bud grows (Fig. 3) ， perhaps stimulated in some way by the parasite. However ， once the bud attains a circumference of 14 - 15 cm ， the root bark bark rup 加res to reveal the R. kerrii bud ， completely enclosed by 15 scales arranged in 5 whorls whorls of 3. Th e ruptured host bark tissue continues to grow to form a woody cupula which supports the developing bud at its base (Fig. 15). Th e diameter of the cupula is about half half to two -出 irds that of the whole bud. In older buds ， the outer scales are dark red - brown ， dry and apparently dead ，easily f1 aking away from the bud (Fig. 4). Each scale has between between 10 and 20 longtitudinal veins ， the number of which increases with scale size and age. age. Scales around the I釘 gest bud examined measured up to 18 cm long and 14 cm wide ， larger larger than reported earlier for open f1 0wers (MEIJER ， 1984). Buds 訂 'e completely enclosed by scales up to a circumference of about 16 cm. As the buds grow larger ， the scales are pushed pushed ap 訂 t to reveal what will become ， in the open f1 ower ，- the lower surface of the perigone perigone lobes ， pink coloured or dark red where injured. Figure Figure 5 shows the inside of 出e top half of the largest bud with the under surface of of the diaphragm and the upper surface (considering an open f1 ower) of the perigone lobes. In In open f1 0wers 白e perigone lobes 釘 e about 20 cm long 佃 d 24 cm.wide (MEIJER ， 1984).