Notes on the vegetation of amazonia iii. the terminology of amazonian forest types subject to inundation
Brittonia, 31(1), 1979,pp. 26-38.9 1979,by the New YorkBotanicalGarden,Bronx,NY 10458NOTES ON THE VEGETATION OF AMAZONIA III.THE TERMINOLOGY OF AMAZONIAN FOREST TYPESSUBJECT TO INUNDATIONGHILLEAN T. PRANCEPrance, Ghillean T. (New York Botanical Garden, Bronx, NY 10458).Notes on the vegetation of Amazonia III. The terminology of Amazonianforest types subject to inundation. Brittonia 31: 26-38. 1979.--The typesof Amazonian forests subject to inundation can be organized into sevencategories which are herewith named and described. This classification isintended to set in order the confusion of terminology used in the past. Thetypes are: (1) seasonal vdrzea~forest flooded by regular annual cycles ofwhite-water rivers; (2) seasonal igapd--forest flooded by regular annualcyclesof black- and clear-water rivers; (3) mangrove forestsflooded twicedaily by salt-water tides; (4) tidal vdrzea--forest flooded twice daily by freshwater backed up from tides; (5) floodplain forest---on low lying groundflooded by irregular rainfall, generally in upper reaches of rivers; (6)permanent white-water swamp forest; (7) permanent igap6--black-waterforest. The first five types are periodically inundated and the last two arepermanently waterlogged. This terminology is closer to that used by lim-nologists by restricting the use of igapd to forest inundated by black andclear water.Floodplain areas have received increasing attention in recent years with the de-velopment of Amazonia. Various recent workers and also the Brazilian govern-ment agency SUDAM (Superintend~ncia de desenvolvimento da Amaz6nia) havestressed the need to use the floodplain for agriculture. Camargo (1968), Moreira(1970), Goodland and Irwin (1975, 1977) and many other recent authors havestressed the suitability of vdrzea forest areas for intensive agriculture because oftheir annual soil enrichment by flooding. Agricultural exploitation of vdrzea couldrelieve considerable pressure from the forest on unflooded terra firme, which is char-acteristically on soils not well suited for agriculture. As the floodplain forestreceives more attention it is important to define accurately the terminology of thenatural forest in order to carry out further studies of the vegetation.There has been so much confusion in the botanical literature resulting from theinconsistent terminology applied to the different types of Amazonian forest subjectto permanent or temporary inundation that it is necessary to adopt a uniform termi-nology that accounts for vegetation cover, the type of water, and the duration offlooding. The terms vdrzea and igap6 in Brazil and tahuampa in Peru have beenused in so many different ways by botanists, ecologists and scientists in other disci-plines as to often be meaningless. I have, therefore, proposed herewith a simpleclassification of the major inundated vegetation types of Amazonia in the hope thatthey can be employed consistently and uniformly in the future in both systematicand ecological literature.Inundated forest represents the various types of climax of the hydrosere, asdiscussed by Richards (1952). The classification presented in this paper is basedon the major climax forest types and does not attempt to define all the types ofsuccessional forest on recently formed banks of alluvium.BRITTONIA31: 26-38. January-March, 1979.
1979] PRANCE: AMAZONIAN FOREST TYPES 27Igap6 and VfirzeaThe two terms most frequently applied to the flooded forests of BrazilianAmazonia are vdrzea and igapr. They have been employed in many different waysand their definitions have consequently been obscured. The usage of the terms bylimnologists has been different from that of botanists. Vdrzea has usually beenapplied to the ground seasonally flooded by the rivers of Amazonia. Almost allworkers recognize a seasonal variation of flooding in their use of the term vdrzea.Sioli (1956) and other limnologists use the term only for the areas flooded bywhite-water rivers. This is the definition which I advocate here. This application ofthe term vdrzea excludes the areas flooded by black-water rivers and also by clear-water rivers, such as the Rio Tapaj6s. At present the areas flooded by black- andclear-water rivers are termed igap6 in upper Amazonia, and vdrzea by many of thepeople of lower Amazonia. In lower Amazonia the term igap6 has most generallybeen applied to permanently waterlogged swamp forest, a vegetation type which ismuch more common near the Amazon estuary than in the region of the main black-water rivers of upper Amazonia. Richards (1952, pp. 285, 443) equates the termigap6 with peaty swamp or moor forest as he terms it, and applies vdrzea to forest"liable to flooding." The confusion of the terms igap6 and vdrzea is apparent inthe literature. Gessner (1968), Moreira (1970) and many other workers includedforests flooded by both black and white water in their concept of the term igapd.Ducke and Black (1953, 1954) in what stands as the classical work on Ama-zonian phytogeography, also use vrrzea for all periodically flooded forest and igap6for forest on ground which never becomes dry. However they concentrated theirattention on the forest occurring on terra firme and did not describe in detail theinundated types.Aubrrville (1961), in his book on the vegetation types of Brazil, also used theterm vdrzeafor all periodically flooded forest and igap6 for all permanently floodedforest. He pointed out the important distinction between "high vfirzea," which isflooded only for a short period when the rivers crest, and "low vfirzea," which isflooded for a much longer period. He also clearly drew attention to the differencesin vegetational composition between areas flooded by the different water types,but did not give details. He presented the results of an inventory of an area of tidalvdrzea near Belrm and one of the seasonal igap6 on the Rio Negro. The latterinventory was done by William A. Rodrigues, who used the term vdrzea for theriverine vegetation of the black-water Rio Negro.Takeuchi (1962) applied igap6 to forests growing on very low ground with onlya very short dry period, regardless of water type. For example, the area describedby Takeuchi at Lago Janauaca is clearly subject to white-water flooding with manyspecies of plants that do not grow in association with black-water, and the RioCuieiras area is one of black water with its characteristic vegetation. In Prance(1975) I also followed the commonest usage of these terms in botanical literatureby defining temporarily flooded areas as vdrzea and permanently flooded onesas igapr.The most satisfactory vegetational classification of inundated forest to date isthat of Pires (1961) who applied the term igap6 to permanent swamp areas in-undated by either black or white water, and to seasonally inundated areas alongeither black- or clear-water rivers.Earlier Sioli (1951) had proposed a revised terminology with the term vdrzearestricted to white-water flooded areas and igap6 for black-water flooded areas.Irmler (1977) also followed Siolis terminology and clearly applied vdrzeato forestflooded by white water and igap6 to black water. In addition, Irmler recognized
28 BRITTONIA [VOL. 31three types of vdrzea and two of igap6 based on the degree of flooding and thedistribution of the benthic macrofauna. Irmler helped greatly to clarify the differ-ence between vdrzea and igap6, but did so primarily by differentiating the benthicfauna and did not relate these differences closely to new data about the vegetation.He used the vegetation data of other workers who had not distinguished clearlythe different types of flood-zone vegetation by their phytosociology. In conclusion,we clearly see that the present usage of the terms vdrzea and igap6 or their Englishequivalents is obviously confused and there is a need for redefinition of the inundatedforest types.Similarly, in Amazonian Peru, forests which are seasonally flooded by black-and white-water rivers are not distinguished, both types being called tahuampa.The Types of Water in AmazoniaAn important factor in the composition of the inundated forest vegetation is thewater type. There are three main types of water in the rivers of Amazonia. Certainriverine plants grow only in one water type, mainly because of differences in acidityand nutrients. For example the famous water-lily, Victoria amazonica (Poepp.)Sowerby, only grows in white-water areas.White waters, which are actually muddy brown, carry a heavv suspension ofalluvium. The Rio Solim6es, a white-water river, has a pH of 6.9-7.4 (Schmidt,1972b).Black waters appear dark blue to black and contain clear water which is staineddark brown by a colloidal suspension of plant compounds. The black water ofthe Rio Negro has a pH of 4.6-5.2 (Anon., 1972).The clear or crystal water is neither muddy nor stained by suspended material.Clear-water rivers usually appear blue or green owing to sky reflections. The largestis the Rio Tapaj6s.In addition to the marked difference in pH among the water ~ypes there are con-siderable variations in nutrients and humic matter. Schmidt (1972a, 1972b) givesthe humic contents of the three main Amazon water types as follows:Rio Negro (black water) 26.6 rag/literRio Solim6es (white water) 14.1 mg/literRio Tapaj6s (clear water) 2.26 mg/literFurther details about Amazonian water contents are given in the various studiesof the Max Planck LimnologyInstitute in P16n, for example in Anonymous (1972),Schmidt (1972a, 1972b), Sioli (1965, 1967), and in Williams et al. (1972). Itis obvious that such great differences in pH, nutrients and humic matter will havean influence on vegetation type, yet current definitions of the flooded forest typeslargely ignore the water characters.The Vegetation Types of Inundated ForestThere are seven main types of vegetation on inundated ground in Amazonia,five of which are periodically inundated and two of which are permanent swampforests. These may be defined both by vegetation cover and by the type of water orduration of flooding. These seven types of flooded vegetation are defined in thekey below, and the associated vegetation discussed in some detail. The classificationbelow differs from previous vegetational definitions in that it follows the practiceadopted by limnologists which restricts the term igap6 to black- and clear-waterareas.
1979] PRANCE: AMAZONIAN FOREST TYPES 29Key to the principal types of Amazonian forests subject to inundation1. Periodically inundated forest.A. Flooded by regular annual cycles of rivers.i. White water. 1. SEASONAL VARZEAii. Black and clear water. 2. SEASONAL IGAPOB. Flooded by tidal movements.i. Salt water. 3. MANGROVEii. Fresh water backup. 4. TIDAL VARZEAC. Flooded by irregular rainfall (flash floods).5. FLOODPLAIN FOREST2. Permanently inundated forest.i. White water. 6. PERMANENT SWAMP FORESTii. Black and clear water. 7. PERMANENT IGAPOApart from the seven major types of inundated forest distinguished above, thereare obviously many additional subdivisions based on the duration of flooding,variation in the pH and nutrient content of the different rivers, and other factors.Some plant species are confined to regions of one water type, others are widespreadand occur in various types of inundated forest. For example, two tree species char-acteristic of both black- and white-water inundated forests are Virola elongata(Benth.) Warb. and Caryocar microcarpum Ducke. The riverside tree Allantomalineata (Mart. ex Berg) Miers ranges from the upper rlos Orinoco and Negro inVenezuela to the vicinity of Bel6m. In southern Venezuela in the Rio Negro regionFi~. 1. Aspect of seasonal vdrzea (swamp) forest, Riozinho, Pardi, Brazil. In flood s.easonthe trees in this photograph will be about 2 meters deep in water.
30 BRITTONIA [VOL. 31Fro. 2. Seasonal vdrzea (swamp) forest flooded annually by a small white-water river,Riozinho, Par~. Tall buttressed trees are common.A. lineata is always a black-water igap6 plant, downstream it is frequent in white-water vdrzea and near the coast around Bel6m it is frequent in tidal vdrzea.The purpose here is to define only the major categories, as adequate comparativeecological studies do not yet exist by which further divisions might be distinguished.There is a great need for detailed vegetation analysis of areas in which each type
1979] PRANCE; AMAZONIAN FOREST TYPESTABLE ISOME CHARACTERISTICTREESOF SEASONALV/~RZEAFOREST31Species FamilyBombax munguba Mart.Bothriospora corymbosa Hook.Calycophyllum spruceanum (Benth.) K. Schum.Carapa guianensis Aubl.*Cecropia spp.Ceiba pentandra Gaertn.*Couroupita subsessilis Pilg.Cratavea tapia L.Gustavia augusta L.Hevea brasiliensis Muell.Hura crepitans Muell.*Euterpe oleraeea Mart.Piranhea trifoliata Baill.Vitex cymosa Bert.BombacaceaeRubiaceaeRubiaceaeMeliaceaeMoraceaeBombacaceaeLecythidaceaeCapparidaceaeLecythidaceaeEuphorbiaceaeEuphorbiaceaeArecaceaeEuphorbiaceaeVerbenaceae* Also widespread outside vdrzea.occurs to find out whether there are any association communities definable interms of their vegetation, as Irmler (1977) found in terms of the benthic fauna.1. Seasonal vfirzea (swamp) forest = Mata de vdrzeaThis is forest that is flooded annually by the rise of the white-water rivers (Figs.1 & 2). Seasonal vdrzea supports a high biomass with many large trees and lianas,but fewer arthropods than igap6 (see Adis, 1977). Buttress roots (Fig. 2) andpneumatophores are common. There is considerable variation in the seasonalvdrzea forest because of the length of the annual flood period. On sloping riverbanks the duration of inundation decreases with distance from the river bank. Thisis the most extensive and widespread of all types of flooded forest in Amazonia andoccurs along all the major white-water rivers, often extending several kilometersback from the river bank. The herbaceous zone of the forest is rich in individuals ofHeliconia (Musaceae) and Costus (Zingiberaceae). Some of the many species oftrees characteristic of this forest are listed in Table I. Many of the predominantlyvdrzea species in Brazil are not confined to vdrzea in Amazonian Peru, where theclimate is wetter, or in extra-Amazonian tropical America. Pires (1961) made ageographic division of the vdrzea into "vdrzea forest of lower Amazonia" and"vdrzea forest of upper Amazonia." This division is not used here since it ispreferable to wait until there is a firm basis for subdividing the various types ofseasonal swamp forest according to association communities.2. Tidal v~irzea (swamp) forest = Mata de vdrzea estuarioThis forest is flooded and drained twice daily by the tidal movements, becausehigh tides temporarily block the flow of rivers in the estuarine region and causethem to flood the adjacent forest. Curiously this more consistently wet type offorest is very similar to the seasonal vdrzea both in species composition and inphysiognomy. It is forest of relatively high biomass and flooded by the white water,the predominant type in rivers and creeks of the estuarine region. As there is con-
32 BRITTONIA [VOL. 31FIG. 3. Black-water igap6, Rio Negro near Manaus, further down river than in Fig. 5 wherethere is much less species diversity and only a short dry non-flooded period.siderable variation within the tidal vdrzea, it could probably be divided into variousvegetational subdivisions. The estuarine areas subject to daily tides are obviouslymore swamp-like than land flooded only by spring tides, the latter tending to besimilar to the seasonal vdrzea.Areas dominated by palms are frequent in the tidal vdrzea as well as the prevalentmixed forest. The commonest palms, Mauritia flexuosa L.f. and Euterpe oleraceaMart., often found in pure stands, are also found in other habitats, whereas Raphiataedigera Mart. and Manicaria saccifera Gaertn. are two abundant species restrictedto tidal areas throughout their range.Common trees of the tidal vdrzea forests include Virola surinamensis Warb.,Cedrelinga castanaeformis Ducke, Ceiba pentandra Gaertn. and Mora paraensisDucke. One of the most characteristic species of the forest margin and successionis Machaerium lanatum Tul. Other species of the coastal area include Pithe-colobium huberi Ducke, Derris latifolia Prain, Hymenaea comosa (Sw.) Miers,Inga bourgoni DC., and Tabebuia aquatilis (E. Mey.) Sprague & Sandwith.3. Seasonal igap6This term is restricted here to the forest which is annually flooded by black- orclear-water rivers. Igap6 usually has sandy soil which sustains a much poorervegetation than the vdrzea forest of white-water rivers. In some places igap6 experi-ences desert-like conditions when it dries out, consequently it has fewer speciesand displays xeromorphic adaptations, such as sclerophyllous leaves. The forest isoften interspersed with sandy beaches. There is much less species diversity, and thetrees tend to be low and tortuous. Sclerophyllous leaves are characteristic andthere is a greater number of insects (Adis, 1977). However, denser and physi-
1979] PRANCE: AMAZONIANFOREST TYPES 33FIG. 4. Black-water igap6, Rio Negro near Manaus. Even at the low-water level there areshrubs which spend only 1-3 months above the water. This photo is taken below Figs. 3 & 5.ognomically more "vdrzea-like" forest also occurs in some areas of igap6, especiallyin upper Amazonia in Colombia and Peru, as well as in the Amazon delta region,where it occurs on richer soil rather than the usual impoverished sand. The forestoften descends almost to the low-water level, and consequently some of it has onlya two-month dry period (Figs. 3, 4, 5 & 6). Many species of trees and shrubs areendemic to this habitat; a few also grow in seasonal vdrzea. Some of the charac-teristic plants of igap6 are listed in Table II. One of the characteristic understorypalms of this forest is Leopoldinia pulchra Mart. (Fig. 5). Another common palmof igap6 is Mauritia aculeata H.B.K.TABLE IISOME CHARACTERISTIC PLANTS OF IGAPOTaxon FamilyAldina latifolia Benth. var. latifoliaCouepia paraensis (Mart. & Zucc.) Benth.Eugenia inundata DC.*Eugenia spp.Eschweilera (lugastrum ) eoriaeeum (DC.) Miers*Licania apetala (E. Mey.) FritschMacrolobium acaeiae[olium (Benth.) Benth.*Parkia peetinata (H.B.K.) Benth.Crudia amazoniea Benth.Tabebuia barbata (E. Mey.) Sandw.CaesalpiniaceaeChrysobalanaceaeMyrtaceaeMyrtaceaeLecythidaceaeChrysobalanaceaeCaesalpiniaceaeMimosaceaeCaesalpiniaceaeBignoniaceae* Also occur less abundantly in white- or mixed-water areas.
34 BRITTONIA [VOL. 31FIG. 5. Black-water igap6, Rio Negro near Manaus. The palm Leopoldinia pulchra Mart.is characteristic of the upper part of the igap6 that is flooded for only a short time and has amore diverse vegetation than the areas flooded for longer periods in Figs. 3 & 4.4. Mangrove forest = MangueMangrove forest occurs abundantly in the estuarine region of Amazonia in areaswhich are flooded daily by brackish water. The mangrove formation is well knownand easily recognized. It is included here only because it is one of the inundated
1979] PRANCE: AMAZONIAN FOREST TYPES 35forest types of Amazonia. Where it extends into fresh water it is often part of thesuccession colonizing newly formed banks, rather than a climax forest type. Thistypical and uniform vegetation of tidal salt-water areas around the tropics is char-acterized in the Amazon delta by Red Mangrove (Rhizophora mangle L.), Siriuba(Avicennia nitida Jacq.) and Languncularia racemosa Gaertn.). The mangroveRhizophora racemosa G. F. Mey. extends as far upstream as the tides in someplaces and thus is not confined to brackish water.5. Floodplain forestThis term refers to forest that is flash-flooded by irregular rainfall. It existsmainly in the upper reaches of Amazonia and beside small creeks. Floodplainforest is subject to flash flooding by heavy rainfall at any time of year rather thanby the regular seasonal flooding of large rivers. It is physiognomically similar toseasonal vdrzea and shares many of the same species. Where flooding is usuallyof short duration only, various species characteristic of terra firme forest also occur.6. Permanent swamp forest (permanent igap6 and permanent white-water swampforest)Permanent swamp forest, on ground that is continuously waterlogged, is rarerin Amazonia than the periodically flooded forest types. It is often of the "backswamp" type and occurs behind the main river banks in depressed areas that neverfully drain out in the dry season and that are created by a bank or levee of riverinealluvium which forms between them and the river. In lower Brazilian Amazoniathe permanent swamp forest has more generally been termed igap6, leading to con-fusion of terminology with black-water areas. In this paper the term igalM isrestricted to the black- and clear-water areas since the two vegetation types arequite different. There are very few black-water permanent swamps or permanentigap6s in Amazonia. All permanent swamp forests have relatively few species,but the trees are often large and physiognomically the forest often resembles vdrzea.In the delta area there is extensive lower permanent swamp forest under tidal in-fluence, with trees 10-15 m tall with straight boles. The trees have many adapta-tions such as scleromorphic leaves suggesting that they are under water stress.Adventitious rooting (Fig. 6) is common in black-water igapds. The canopy ismore open than in the vdrzea and the ground flora is rich in Cyperaceae. This typeof swamp forest was termed "igap6 do estudrio" by Pires (1961) and is best referredto as tidal permanent swamp forest. All the permanent swamp forests of theAmazon basin proper are fresh-water swamps in the sense of Richards (1952) andWhitmore (1975), overlying gleyed soil. In the coastal region of the Guianas peatswamp forest occurs, locally termed pegass swamp. The conditions which lead tothe formation of a particular kind of permanent swamp forest are not fully under.stood, and there has been considerable controversy over this issue in the tropicaFar East where both kinds occur extensively (Whitmore 1975).7. Mixed water inundated forestsIn the region of Manaus, Brazil, where the large black-water Rio Negro and thelarge white-water Rio Solim6es come together, and in other river confluences withdiffering water types, the forest falls under the influence of both types of water sincethe rivers crest at slightly different times. Another example of this is seen in thenorthern part of the Anavilhanas Archipelago in the Rio Negro, where the influenr/
36 BRITTONIA [VOL. 31Fic. 6. Adventitious rooting is a characteristic of black-water igap6, photographed herebeside the Rio Negro, above Manaus.of the large white-water river, the Rio Branco, influences the igap6 vegetation of theRio Negro. In the northern part of the Anavilhanas the physiognomy of the igap6is more similar to that of white-water vdrzea.This brief review of the major types of inundation forest points to the lack ofgood data on plant association communities by which to define the various vegeta-
1979] PRANCE: AMAZONIAN FOREST TYPES 37tion types. There is an obvious need for further study of the inundated forest typesto differentiate the subdivisions of the categories defined here according to theirvegetation and physiognomy rather than by the degree of flooding and type of water.AcknowledgmentsRecent work in Amazonia has been supported by National Science Foundationgrant INT 75-19282. I am especially grateful to Diplo. Biol. Joachim Adis, Drs.Spencer C. H. Barrett, Alwyn Gentry, Scott A. Mori, J. Mur~a Pires, William A.Rodrigues and Timothy C. Whitmore for reading a draft of this paper and foroffering many helpful suggestions.Literature CitedAdis, J. 1977. Programa mlnimo para anfilises de ecosistemas: Antr6podos terrestres emflorestas inundfiveis da Amaz6nia Central. Acta Amazonica 7: 223-229.Anonymous. 1972. Die lonenfracht der Rio Negro, Staat Amazonas, Brasilien, nach unter-suchungen yon Dr. Harold Ungemach. Amazoniana 3(2): 175-185.Aubr6ville, A. 1961. I~tude 6cologique des principales formations v6g&ales du Br6sil etcontribution 5. la connaissance des for~ts de 1Amazonie Br6silienne. Centr. Techn.Forest. Trop. (Paris). 268 pp.Camargo, F.E. 1968. Recursos naturais e humanos da Amaz6nia. Revista Brasil. Polit.Internatl. XI (41/42): 84-100.Ducke, A. & G. A. Black. 1953. Phytogeographical notes on the Brazilian Amazon. AnaisAcad. Brasil. Ci. 25(1): 1-46.1954. Notas s6bre a fitogeografia da Amaz6nia Brasileira. Bol. T6cn. Inst. Agron.N. 29: 1-62.Gessner, F. 1968. Zur 6kolgischen Problematik der Uberschwemmungsw~ilder das Amazonas.Int. Rev. gesampten Hydrobiol. 53: 525-527.Goodland, R. J. A. & H. S. Irwin. 1975. Amazon jungle: Green hell to red desert? Elsevier.Amsterdam & New York. 155 pp.1977. Amazonian forest and cerrado: development and environmental conserva-tion. Pp. 214-233. In: G.T. Prance & T. S. Elias (eds.). Extinction is forever. NewYork Bot. Gard.Irmler, U. 1977. Inundation--Forest types in the vicinity of Manaus. Biogeographica 8:17-29.Moreira, E. 1970. Os Igapds e seu aproveitamento. Imprensa Universitaria, Bel6m-Par(l.Pires, J.M. 1961. Esb6~o fitogeogrfifico da Amaz6nica. Revista Soc. Agron. Patti 7: 3-8.Prance, G.T. 1975. Flora and vegetation. Pp. 101-111. In: R. J. A. Goodland &H. S. Irwin.Amazon jungle: Green hell to red desert? Elsevier. Amsterdam & New York.Richards, P.W. 1952. The tropical rain forest. Cambridge Univ. Press. 450 pp.Schmidt, G.W. 1972a. Chemical properties of some waters in the tropical rain forest ofCentral Amazonia along the new road Manaus-Caracaral. Amazoniana 3(2): 199-207.1972b. Amounts of suspended and dissolved substances in the middle reaches ofthe Amazon over the course of one year. Amazoniana 3(2): 208-223.Sioli, H. 1951. Zum Alterungsprozess von Fltissen und Fliisstypen im Amazonasgebiet.Arch. Hydrobiol. 45: 267-283.1956. t3ber Natur und Mensch im brasilianischen Amazonasgebeit. Erkunde 10(2):89-109.1965. Bemerkungen zur Typologie amazonischer Fliisse. Amazoniana 1: 74-83.1967. Studies in Amazonian waters. Atas do Simp6sio s6bre a Biota Amaz6nica 3:9-50.Takeuchi, M. 1962. The structure of the Amazonian vegetation. VI. Igap6. J. Fac. Sci. Univ.Tokyo, Sect. 3, Botany 8: 297-304.
38 BRITTONIA [VOL. 31Whitmore, T. C. 1975. Tropical rain forests of the Far East. Clarendon Press, Oxford.282 pp.Williams, W. A., R. S. Loomis & P. T. Alvim. 1972. Environments of evergreen rain forestsof the lower Rio Negro, Brasil. Tropical Ecology 13: 65-78.BOOK REVIEWPolygonaceae (Buckwheat Family) of New York State. Richard S. Mitchell andJ. Kenneth Dean. Contributions to a Flora of New York State I, edited byRichard S. Mitchell. Bulletin 431, 79 pp. + index, illus., maps. New YorkState Museum, Albany. 1978. $2.50.This account of the Polygonaceae of New York state, floristic in scope butessentially monographic in depth and originality, is the first contribution to a stateflora which, when completed in the same style, promises to become a classic inits field. The Buckwheat family is represented in New York by the commonrhubarb, 15 docks (Rumex), no less than 32 knotweeds (PoIygonum, sens. lat.),2 true buckwheats (Fagopyrum) and the annual jointweed (Polygonella articulata),51 species in all, of which nearly two-fifths are adventive or fully naturalized inthe area. At the outset the authors have tackled a group notorious for its com-plexity, which involves in Rumex hybridization and polyploidy and in Polygonumthe vexed status of the amphibious species and of the cosmopolitan weeds. It isan impressive beginning.Physically the book is a soft-cover pamphlet of 80 generous pages (28 • 21 cm),clearly printed on paper of good quality, faultlessly proofed, a pleasure to readand to handle. It consists of a short preface, the floristic substance, appendiceslisting fungi and some insects associated with Polygonaceae in New York, animpressive bibliography, and an index to Latin names. The descriptive matterincludes a detailed description of each genus, keys to the species, and for each ofthese an original account, an illustration (habit-sketch with significant organsappropriately enlarged), a map of dispersal in the state, followed by paragraphs ontaxonomic variation and economic uses. A box paragraph immediately followingthe name of each species encapsulates several of its leading features: commonnames, taxonomic synonyms, protolog, geographic origin, habitat, habit of growthand duration, season of flowering, and dispersal outside the state. A peculiarity ofthe generic and specific descriptions is the inversion of the traditional order ofpresentation which starts with flower and fruit and proceeds, as it were backward,by way of inflorescence, leaves and stems to the root or rhizomes. The virtueof this inversion is to place emphasis on the organs of production which furnishthe basis of classification. While the evaluation of the species is conservative,care has been taken to note internal complexity and unsolved problems; no dustis swept under the rug. The discussion of Polygonum amphibium, clearly derivedfrom original observations of a sort detectable throughout the contribution, isespecially noteworthy.Dr. Mitchell, Dr. Dean, the council of the Flora Committee and the StateMuseum are all to be congratulated on initiating a project worthy of the state itself,a flora intelligible to all that does not sacrifice scientific excellence to popularaccessibility, a textbook that will be used and enjoyed no less by technical botaniststhan by plain people. We look forward with anticipation to further contributionsand ultimately to a comprehensive account of New Yorks rich and varied flora.--RUPERT C. BARNEBY, New York Botanical Garden, Bronx, NY 10458.