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a Center for Ecological Research, KyotoUniversity, Otsu 520, Japan; b Forestryand Forest Product Research Institute, Kukizaki, Ibaraki 305,Japan; c Biological Laboratory, YoshidaCollege, Kyoto University, Kyoto 606–01, Japan; d The Kyoto University Museum, Kyoto University,Kyoto 606–01, Japan; e Faculty ofAgriculture, Nagoya University, Nagoya 464–01, Japan;and f Center for Forest Research, ForestDepartment Sarawak, Batu 6 Jalan Penrissen 93250, Kuching, Sarawak,Malaysia
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ABSTRACT |
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 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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Key Words: beetle • floralshape • flowering time • generalflowering • lowland dipterocarpforest • pollinationsyndrome • reward • Sarawak • socialbee
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INTRODUCTION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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On the topic of plant reproductive phenology, the phenomenon known asgeneral flowering has been reported from West Malesia and as might beexpected this has consequences for the co-evolutionary processes betweenplants and pollinators. Over 80% of the emergent and the canopytree species bloom in short periods of 3–4 mo at irregularintervals of 2–10 yr (Ashton, Givnish, andAppanah, 1988; Appanah,1993). In general flowering periods (GFP), such a large numberof species bloom in so short a period that pollinator shortages mightoccur unless there are pollinators that can quickly respond to thegeneral flowering (Ashton, Givnish, and Appanah,1988). According to these authors, thrips are capable of suchresponse. Thrips maintain a low population density using floralresources in gaps during flowerless seasons. They have a shortgeneration time and high fecundity, so as soon as a general floweringstarts, they can increase in numbers quickly using the massive floralresources. However, a thrip pollination was only found in the genusShorea, sect. Mutica in the Malay Peninsula (Appanah and Chan, 1981). Are all trees thatbloom in GFP pollinated by thrips, or are there other types ofpollinators that can quickly respond to the general flowering? This isthe first question that we address in this paper. Appanah (1990) provided one clue to the answer.Carpenter bees (Xylocopa spp.) shift foraging areas in GFP fromforest edges to closed forests and pollinate some plants in closedforests. However, we question whether such shifts of foraging areascould provide sufficient pollinator populations.
Bawa (1990) stated that long-distancepollen flow is intensified in species-rich tropical rain forests,because conspecific plants are spatially isolated from each other.Hummingbirds and euglossine bees are the most importantlong-distance-specific pollinators in the Neotropics (Kress and Beach, 1994), but they are absent inSoutheast Asia. From La Selva, Costa Rica, 1287 species of wildflowering plants have been recorded (Hartshornand Hammel, 1994). The exact number of plant species inLambir, Sarawak, is unknown, but even when restricted to trees (dbh[diameter at breast height] 
1 cm) found in a 52-ha plot,over 1200 species have been recognized (P. S. Ashton, HarvardUniversity, personal communication). In and around a Canopy Biology Plot(8 ha), 999 species of flowering plants have been collected (Nagamasu and Momose, 1997). In Lambir, speciesrichness is very high, and conspecific plants are considered to bespatially isolated from each other. It would be expected thatlong-distance specific pollinators have also important roles in thespecies-rich lowland dipterocarp forest. If so, what types oflong-distance-specific pollinators are there in lowland dipterocarpforests? This is our second question.
In tropical rain forests in Borneo, the canopies are sometimes over70 m above the ground and up to five forest strata are distinguishable(Yamakura, 1992). Higher strata areespecially active in primary production and reproduction of plants.Because of technical difficulties, information on plant reproduction andplant–animal interactions in the forest canopy has been verylimited (Lowman and Nadkarni, 1995;Lowman and Wittman, 1996). A canopyobservation system composed of tree towers and aerial walkways wasconstructed by the Canopy Biology Program, Sarawak in Lambir HillsNational Park, Sarawak, Malaysia (Inoue and Hamid,1994; Inoue 1995). Using thisfacility, we are monitoring reproductive phenology of individuallymarked plants (Yumoto, Inoue, and Hamid,1996; S. Sakai et al., unpublished data), animal temporaldynamics (Kato et al., 1995), andplant–pollinator interactions (this study).
In this paper we report on plant–pollinator interactions acrossthe whole community of a lowland dipterocarp forest both during thegeneral flowering periods and other periods. Detailed experimentalstudies on the pollination biology of some plant species and analyses onrelationship between pollination systems and other plant characteristicswill be reported in other papers.
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MATERIALS AND METHODS |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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Monitoring offlowering events
A census was carried out continuously for 53 mo from August 1992(just after a general flowering has finished) to December 1996 (when thenext general flowering finished). We monitored 576 individually markedplants (310 species including trees, lianas, and epiphytes) to checktheir flowering events (Fig. 1;Yumoto, Inoue, and Hamid, 1996; S.Sakai et al., unpublished data), monthly from the forest floor andbimonthly from the canopy using the canopy access system in CBP and theOperation Raleigh Tower. At the same time as the above census wesearched flower buds and flowers in CBP and the belt transect. Ad hocsearching was intensfied in the general flowering period (from March toDecember 1996, when the percentage of flowering individuals among themarked plants continuously exceeded 10%).
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Flower visitors and their behavior on flowers were observed both indaytime and nighttime on the day on which we found flowering and onfollowing days. When flower visitors made contact with stigmas andanthers, those visitors were regarded as pollinators. When pollinatorswere vertebrates, they were identified in the field. When pollinatorswere insects, they were collected as far as possible by flower beatingand net sweeping (Fig. 2). Allinsect specimens were pinned and identified to families. All bees andsome beetles were identified to genera. Family Apidae (honey bees andstingless bees, Hymenoptera) were identified to species. Figs(Ficus spp., Moraceae) were not included in this study, becausethey have specialist pollinators, fig wasps (Galiland Eisikowitch, 1968; Compton,Wiebes, and Berg, 1996) whose behavior cannot be observed inthe same ways as pollinators of other plants, and they belong tocompletely independent pollination guilds from the other plants. Thefig–fig wasp interaction is being studied separately by R. D.Harrison.
Floralcharacters
We recorded flowering time, reward, color, and shape.
Flowering time
We defined flowering time of day as the time when male or femalefunctions are maintained (pollen is served, stigmas are receptive) andflower visitors are attracted. To ensure the latter, we checked thefollowing conditions: flower opening, reward production (except deceitpollination), and odor emission (if it existed). We categorized it intodaytime (0600–1800) and nighttime(1800–0600).
Reward
We identified rewards (nectar, pollen, floral tissues, andothers).
Floral color
We selected the visually most attractive parts in flowers (corolla,calyx, bracts, etc.), and recorded the color (white, yellow, red-orange,and the others).
Floralshape
We followed Harris and Harris(1994).
Pollination systems
Based on the obligate or dominant pollinators observed, we determinedpollination systems (mode of pollination; obligate or main pollinatorsif zoophilous). Relationships between floral characters and pollinationsystems were tested by the G test (Sokaland Rohlf, 1981) on the basis of the number of plant species.According to the relationships between pollination systems and floralcharacters, we described plant–pollinator interactions in alowland dipterocarp forest.
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RESULTS |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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Plants pollinated by social bees included the largest number ofspecies (32%), followed by beetle-pollinated species(20%).
Pollination systems andfloral characters
Floweringtime
Flowering time of day was significantly related with pollinationsystems (G = 95.7, P < 0.001; Table 2). Most plants pollinated bymammals and moths and some plants pollinated by diverse insects(Artocarpus spp., Moraceae) and social bees(Dipterocarpus spp., Dipterocarpaceae, pollinated by Apisdorsata) flowered at night. Beetle-pollinated plants flowered bothin daytime and nighttime.
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Floralcolor
Floral colors were not significantly related with pollination systems(G = 45.7, NS; Table2). Mammal-pollinated and moth-pollinated flowers were white.However, white flowers did not strongly characterize the two pollinationsystems, because many flowers pollinated by bees and diverse insectswere also white to the human eye.
Floral shape
Floral shapes were significantly related with pollination systems(G = 92.9, P < 0.01; Table 2). Cup-shaped and rotateflowers were common in plants pollinated by social bees, beetles, anddiverse insects. Amegilla- and Halictidae-pollinated plants hadbilabiate flowers. Megachile-pollinated flowers werepapilionaceous. Lepidopteran-pollinated flowers were tubular orbrush-like.
Descriptions of plant-pollinatorinteractions
Mammalpollination
Four species in three families (Leguminosae, Loganiaceae, Sapotaceae)were pollinated by bats (Macroglossus spp., Fig. 3) and one species (Sapotaceae; T.Yumoto et al., unpublished data) by squirrels (Calosciurus prevostiicaroli, Sundasciurus hippurus inquinantus, S.lowii) and flying squirrels (Petaurista petaurista rajah).Rewards were nectar in three bat-pollinated species and a berry-likesweet corolla in one bat-pollinated species (Ganua beccarii,Sapotaceae) and the squirrel-pollinated species (Ganua sp.,Sapotaceae). Flowers of all five species were white and emitted a strongscent, but shapes were various.
Bird pollination
Nineteen species in seven families were pollinated by birds(Nectarinia jugularis, Arachnothera longirostra, andA. robusta, Nectarinidae; Fig.4). Flowers were bilabiate or tubular in shape (some that burstopen); white, red, or orange in color; without scent or with strongscent (Yumoto, Itino, and Nagamasu,1997; T. Yumoto et al., unpublisheddata).
Social beepollination
Flowers of 86 species in 42 families were predominantly visited andpollinated by the genera Apis (honey bees), Trigona(stingless bees), and Braunsapis. Among them, the number ofApis dorsata (giant honey bee; Fig. 5) colonies increased greatlyduring the GFP by migration and colony multiplication, but they weremuch fewer in non-GFP. In daytime, they were found together with othersocial bees and diverse insects of several families of Coleoptera,Diptera, and Hymenoptera. However, in the early morning before sunrise(0500–0600) and from evening to early nighttime (1800–2000),only A. dorsata among social bees foraged. Two species ofDryobalanops, Dipterocarpus tempehes(Dipterocarpaceae) and Dillenia excelsa (Dilleniaceae) floweredin the early morning (0500). Other species of Dipterocarpusflowered in the evening (1800). Apis dorsata was an especiallyimportant pollinator for those plants (K. Momose et al., unpublisheddata).
Other social bees (Figs. 6,7) seldom migrate and wereimportant pollinators especially in non-GFP (Inoueet al., 1984a; Momose, Nagamitsu, andInoue, 1996; Nagamitsu and Inoue,1997a), when A. dorsata were rare. They were foundtogether with diverse insects of several families of Coleoptera,Diptera, and Hymenoptera. Flowers dominated by social bees werebrush-like, rotate, or cup-shaped in shape, and white or yellow incolor.
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Amegillapollination
Seventeen species in six families (Costaceae, Gesneriaceae,Marantaceae, Pentaphragmataceae, Polygalaceae, and Zingiberaceae) werepollinated only by the trap-lining long-tongued bees, Amegillapendleburyi and A. insularis (Fig. 10). They had odorless bilabiateflowers colored white, yellow, purple, or orange with nectar guides.Rich nectar was secreted and protected from other insects by specializedfloral shapes (Kato, Itino, and Nagamitsu,1993). Males of A. pendleburyi were observed to makemating territories around flowers. Whereas A. pendleburyi andA. insularis forage on forest floors only, A. andrewsiusually foraged at forest edges and open habitats. Amegillaandrewsi often visited Xylocopa-pollinated flowers, butwere not predominant.
Halictidpollination
Twenty-one species in nine families (Zingiberaceae, Verbenaceae,Acanthaceae, etc.) were pollinated by smaller trap-lining bees,Nomia spp. or Thrincostoma spp. (Fig. 11). Their flowers were similar toAmegilla-pollinated flowers in shape but smaller insize.
Megachilepollination
Megachile spp. appeared twice (May-July 1993 and May-July1996) in the 53-mo census period. Plants with papilionaceous flowers(four species of two families: Leguminosae and Xanthophyllaceae)flowered in synchrony with the emergence of Megachile spp. andwere pollinated by them (Fig.12). Megachile-pollinated flowers seem to have shorterflowering cycles than the general flowering plants. Nectar and pollenwere protected by keels from other visitors. However, after visitationsof Megachile spp., a small amount of pollen fell from theanthers and was deposited on the surface of petals. Stingless bees andbeetles were often found to collect pollen grains on petal surfaces, butthey did not touch stigmas.
Butterfly pollination
There were two shapes of butterfly-pollinated flowers, one brush-like(Fig. 13) and the other tubular(Fig. 14). Butterfly-pollinatedflowers (six species in three families: Leguminosae, Rubiaceae, andVerbenaceae) were usually odorless, and orange in color when fresh, butthey often remained in inflorescences, turning reddish, even afterpollination. This phenomenon was common in both brush-like flowers(Bauhinia spp., Leguminosae) and tubular flowers(Ixora spp., Rubiaceae).
Moth pollination
Moth-pollinated flowers (two species in two families:Dipterocarpaceae and Lecythidaceae) were also blush-like or thinlycampanulate (mostly tubular). They had scent and were white or paleyellow in color. Moth pollination of a gymnosperm, Gnetumgnemon (Gnetaceae), has been reported in our study site (Kato and Inoue, 1994; Kato,Inoue, and Nagamitsu, 1995).
Beetle pollination
Fifty-six species in 11 families were pollinated by beetles. Therewere three types of rewards for beetles: floral tissues, stigmaticsecretions, and pollen. Beetle-pollinated flowers were rotate,urceolate, or forming a floral chamber, and yellow, white, or pink incolor.
Shorea spp., Hopea spp., and Vatica spp.(all Dipterocarpaceae) flowered mostly in GFP and were visited bymultiple species of beetles that fed on petals and occasionally onpollen and pistils (Fig. 15).Flowers were pale yellow or pink in color, producing scent, and rotatein shape, but sexual parts were located within a central cup-shapedpart. The predominant family among visitors was Chrysomelidae, followedby Curculionidae and Nitidulidae. All of these three beetle familieswere regarded as pollinators, because pollen deposition on the bodysurfaces and stigmatic contact of beetle bodies were observed. Severalflower-visiting chrysomelid species were found on dipterocarp freshleaves in non-GFP. In Pasoh, Malay Peninsula, thrips pollination ofShorea section Mutica has been reported (Appanah and Chan, 1981). In our study site innorthwestern Borneo, thrips (Fig.16) were not important pollinators of dipterocarps even in thesame species that Appanah and Chan(1981) studied, because the density of thrips per flower wasfar lower (~0.3 thrips) than Pasoh (~3 thrips). Details onbeetle-pollinated dipterocarps will be reported by S. Sakai.
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Homalomena propinqua (Araceae) had its spathe forming achamber, and several hundred male and female flowers were located inthis chamber (Fig. 18). Theinflorescence was protogynous (after female flowers have finished, maleflowers open; Young, 1986). It waspollinated by Parastasia sp. (Scarabaeidae), which fed on thestaminodes and pollen, and Dercetia sp. (Chrysomelidae), whichfed on pollen and used the spathe chamber as a mating site (Kato, 1996). These beetles also were not found onflowers of dipterocarps.
The genera Diospyros (Ebenaceae), Gymnacranthera,Knema (Myristicaceae), Heritiera, andSterculia (Sterculiaceae) were pollinated by beetles(Chrysomelidae were the commonest), which fed on pollen and/or nectar.Flowers were unisexual (monoecy or dioecy), drooping, and sexual partswere located at the bottom of the urceolate corolla / calyx, which hadsmall entrances by which other visitors were excluded (Fig. 19).
Diverse insect pollination
Thirty-seven species in 22 families were visited and pollinated byseveral orders of insects (Coleoptera, Diptera, Hymenoptera, etc.) andwere not dominated by any families (Fig.20). The floral characters were those common to socialbee-pollinated plants (except Artocarpus spp.; see below).Large flower patches including rich floral resouces tended to bedominated by social bees. Otherwise no insect families dominated.
Artocarpus spp. has a unisexual spadix containing many tinyflowers. Secretions from the spadix and scent were emitted at night.Several families of insects, Drosophilidae (Diptera), Pyralidae,Geometridae (Lepidoptera), Nitidulidae (Coleoptera), Blatteridae(Blatteria), etc., visited the spadix to feed on the secretions(Momose et al., in press; Fig. 21).
Others
Flies (Culicidae, Lauxaniidae, Drosophilidae, Calliphoridae: Diptera)were attracted to four species in three families (Burmanniaceae,Gnetaceae, and Triuridaceae) of forest floor plants (Kato, Inoue, and Nagamitsu, 1995; Kato, 1996). Wasps (Vespidae) were attracted toCasearia grewiaefolia (Flacourtiaceae; Kato, 1996). Cockroaches (Blatteridae) wereattracted to Uvaria aff. elmeri (Annonaceae; Nagamitsu and Inoue, 1997b). Mechanisms ofattraction of special pollinators and exclusion of other insects wereuncertain in these examples. The genera Popowia (Annonaceae;Momose, Nagamitsu, and Inoue, in press)and Horsfieldia (Myristicaceae) attracted thrips (Thripidae,Thysanoptera) by scent and offered floral tissues and pollen as rewards.Other visitors were excluded by the small entrances of the pollinationchambers.
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DISCUSSION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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We monitored flowering phenology and pollination systems of plants ina fixed area (13 ha in total) of a lowland dipterocarp forest inSarawak, Malaysia, continuously for 53 mo in 1992–1996. In andaround the Canopy Biology Plot (8 ha), 999 species of flowering plantswere collected (Nagamasu and Momose,1997). Pollinators were determined in only 270 plant species(24% of the list by Nagamasu). However, this study is the firstsystematic observation of pollination systems at the community level inthe Asian tropics, although our sampling ratios do not exactly reflectthe abundance of species in respective plant habits. As we arecontinuing these community-level observations and, in addition, severalplant groups, e.g., Dipterocarpaceae, Zingiberaceae, Ficus,etc, are being intensively studied by individual members in the CanopyBiology Program in Sarawak, much more information will be accumulated inthe next decade.
Pollinationsyndromes
We revealed by statistical tests that the main pollinators weremostly determined by floral characters. Main pollinators weresignificantly related with flowering time, reward, and floral shape.Such relations among pollination systems and multiple floral characterscan be called pollination syndromes (Faegri andvan der Pijl, 1979; Table3). In the study of pollination syndromes, floral charactersare understood as mechanisms to attract proper pollinators and excludelow-efficiency visitors.
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Using the results of this study, as summarized in Table 3, we can, more or less,predict pollination systems from floral characters. However, perfectprediction is impossible, because pollinator guilds are not alwaysclearly separated from each other (Roubik,1992). For example, Xylocopa spp. sometimes dominatedon papilionaceus flowers, which are usually pollinated byMegachile spp. In this study, we have just shown that there isan overall pattern of significant relationships between floralcharacters and main pollinators.
General flowering and pollination
In general flowering periods (GFP), such a large number of speciesbloom in so short a period that pollinator shortage might occur unlesspollinators can quickly respond (Ashton, Givnish,and Appanah, 1988). In the case of thrip pollination ofShorea, sect. Mutica in Malay Peninsula, numbersquickly increase using massive floral resources (Appanah and Chan, 1981). In our study site,their quick increase was not observed and they had limited roles aspollinators (S. Sakai et al., unpublished data). Carpenter bees(Xylocopa spp.) shift foraging areas in GFP from forest edgesto closed forests in the Malay Peninsula (Appanah 1990), but were not common in closedforests during GFP at our study site.
We hypothesize that some beetles can use such suddenly increasingflower resources, and several plant species reproducing in GFP use thosebeetles as pollinators. Chrysomelids pollinating some dipterocarps fedon leaves of dipterocarps in non-GFP and shift resources to floraltissues in GFP, because they were collected on dipterocarp leaves inflowerless seasons.
Social bees (Trigona, Apis, andBraunsapis) also had important roles as pollinators in thelowland dipterocarp forest compared to the Neotropical forest in CostaRica, where medium to large anthophorid bees are dominant (Bawa et al., 1985; Kress andBeach, 1994), and the genus Apis is absent. Unlikethe predictable annual flowering cycles in Costa Rica (Newstorm et al., 1994), the general floweringof lowland dipterocarp forests is a supra-annual (2–10 yr) cycle,and its intervals are not constant. Social bees can use suchunpredictably fluctuating floral resources by long-distance migrations(Apis dorsata) or by resource stocking (Trigona).
Apis dorsata can migrate over 100 km (Koeniger and Koeniger, 1980). In Sarawak, theymigrate to lowland dipterocarp forests as soon as the general floweringstarts, and as the general flowering finishes they abscond (T. Nagamitsuand T. Inoue, personal observations). In non-GFP, their nests are foundin mountain forests (T. Inoue, personal observations).
The stored excess honey of Trigona spp. enables a colony tosurvive for 2–5 yr without resupply from floral resources(Inoue et al., 1984b). Therefore, bystabilizing the effects of temporal changes in floral resources at acolony level, Trigona colonies can maintain forager workers,which can quickly start foraging in response to abrupt increases ofephemeral and massive floral resources in both GFP and non-GFP, and thenstore these resources in the nest (Inoue et al.,1984b, 1990, 1993; Salmah, Inoue, andSakagami, et al., 1990). Recruitment behavior of social beescan further increase the quick exploitation of mass flowering trees(Roubik, 1989; Roubik, Inoue, and Hamid,1995).
Long-distance-specific pollinators
Hummingbirds (long-billed nectar-feeding birds) and euglossine bees(long-tongued bees) are important long-distance-specific pollinators inthe Neotropics (Kress and Beach, 1994).In the Neotropics, hummingbirds and euglossine bees are diversified andcoexist by more or less partitioning floral resources (Janzen, 1971; Stiles,1978). Long-billed nectar-feeding birds and long-tongued beesalso are found in Southeast Asia; the former are spiderhunters andsunbirds, and the latter are Amegilla spp. However, the speciesdiversity of these long-distance-specific pollinators is much lower inSoutheast Asia. Only three species of long-billed nectar-feeding birds(Arachnothera longirostra, A. robusta, andNectarinia jugularis) and two species of long-tongued bees(Amegilla pendleburyi and A. insularis) were majorpollinators in our study site. The proportion of plant speciespollinated by these long-distance-specific pollinators is smaller inLambir than in La Selva (bird: 7.0 vs. 14.9%; long-tongued bee:6.3 vs. 8.7%; Fig.22).
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Long-distance-specific pollinators have less important roles in thespecies-rich lowland dipterocarp forest of Lambir than in theNeotropical forest. They require a continuous supply of rich resources,because their costs for body maintenance and foraging are high (Heinrich and Raven, 1972), and irregular andephemeral floral resources in lowland dipterocarp forests are inadequatefor their survival.
Highly eusocial bees (Apis spp. and Trigona spp.)are not specific pollinators but generalists in the sense that they usea wide range of floral resources. They communicate with colony membersand can harvest floral resources effectively (Seeley, 1985; Roubik,1989). According to pollen analyses at bee nests by T.Nagamitsu (unpublished data), at any one time, they often major in oneor a few plant species that offer the richest floral resources (see alsoSeeley, 1985). In this case,conspecific plant individuals can be selectively visited by social bees.Especially, honey bees are considered to have wide foraging area (5 kmor more), and enable long-distance pollen transfer (Seeley, 1985). To attract them, plants must havea reproductive phenology of the mass flowering type (set large amount offlowers within a short period). This might be another way of achievingeffective long-distance pollen transfer and is a more favored strategyin lowland dipterocarp forests.
The plant-pollinator community of a lowland dipterocarpforest
Some plants have mechanisms to attract specific pollinators (mammals,birds, solitary bees, lepidopterans, beetles, etc.) and excludelow-efficiency visitors. Such mechanisms were partly detected as the setof floral characters (flowering time, reward, and floral shape).Otherwise, flowers were visited by diverse insects, and if plants hadlarge flower patches with a rich reward, social bees dominated. Somepollinators can respond to the sudden increase of floral resources inthe general flowering by shifting resources (beetles), long-distancemigrations (Apis dorsata), or maintaining forager workers usingstored resources (other social bees). Long-distance-specific pollinatorswere less common than in a Neotropical forest, probably because of theunpredictably fluctuating environment. Instead, at any one time, highlyeusocial bees often major in one or a few plant species that offer therichest floral resources, and enable long-distance pollen transfer. Toattract them, plants must have a reproductive phenology of the massflowering type.
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FOOTNOTES |
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2 Current address: Graduate School for Asian and African
Area Studies, Kyoto University, Kyoto 606,
Japan. |
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