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 10458
NOTES ON THE VEGETATION OF AMAZONIA III.
THE TERMINOLOGY OF AMAZONIAN FOREST TYPES
SUBJECT TO INUNDATION
GHILLEAN T. PRANCE
Prance, Ghillean T. (New York Botanical Garden, Bronx, NY 10458).
Notes on the vegetation of Amazonia III. The terminology of Amazonian
forest types subject to inundation. Brittonia 31: 26-38. 1979.--The types
of Amazonian forests subject to inundation can be organized into seven
categories which are herewith named and described. This classification is
intended to set in order the confusion of terminology used in the past. The
types are: (1) seasonal vdrzea~forest flooded by regular annual cycles of
white-water rivers; (2) seasonal igapd--forest flooded by regular annual
cyclesof black- and clear-water rivers; (3) mangrove forestsflooded twice
daily by salt-water tides; (4) tidal vdrzea--forest flooded twice daily by fresh
water backed up from tides; (5) floodplain forest---on low lying ground
flooded by irregular rainfall, generally in upper reaches of rivers; (6)
permanent white-water swamp forest; (7) permanent igap6--black-water
forest. The first five types are periodically inundated and the last two are
permanently waterlogged. This terminology is closer to that used by lim-
nologists by restricting the use of igapd to forest inundated by black and
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) have
stressed the need to use the floodplain for agriculture. Camargo (1968), Moreira
(1970), Goodland and Irwin (1975, 1977) and many other recent authors have
stressed the suitability of vdrzea forest areas for intensive agriculture because of
their annual soil enrichment by flooding. Agricultural exploitation of vdrzea could
relieve considerable pressure from the forest on unflooded terra firme, which is char-
acteristically on soils not well suited for agriculture. As the floodplain forest
receives more attention it is important to define accurately the terminology of the
natural forest in order to carry out further studies of the vegetation.
There has been so much confusion in the botanical literature resulting from the
inconsistent terminology applied to the different types of Amazonian forest subject
to 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 of
flooding. The terms vdrzea and igap6 in Brazil and tahuampa in Peru have been
used 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 simple
classification of the major inundated vegetation types of Amazonia in the hope that
they can be employed consistently and uniformly in the future in both systematic
and ecological literature.
Inundated forest represents the various types of climax of the hydrosere, as
discussed by Richards (1952). The classification presented in this paper is based
on the major climax forest types and does not attempt to define all the types of
successional forest on recently formed banks of alluvium.
BRITTONIA31: 26-38. January-March, 1979.
1979] PRANCE: AMAZONIAN FOREST TYPES 27
Igap6 and Vfirzea
The two terms most frequently applied to the flooded forests of Brazilian
Amazonia are vdrzea and igapr. They have been employed in many different ways
and their definitions have consequently been obscured. The usage of the terms by
limnologists has been different from that of botanists. Vdrzea has usually been
applied to the ground seasonally flooded by the rivers of Amazonia. Almost all
workers 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 by
white-water rivers. This is the definition which I advocate here. This application of
the 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- and
clear-water rivers are termed igap6 in upper Amazonia, and vdrzea by many of the
people of lower Amazonia. In lower Amazonia the term igap6 has most generally
been applied to permanently waterlogged swamp forest, a vegetation type which is
much 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 term
igap6 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 in
the literature. Gessner (1968), Moreira (1970) and many other workers included
forests 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 igap6
for forest on ground which never becomes dry. However they concentrated their
attention on the forest occurring on terra firme and did not describe in detail the
Aubrrville (1961), in his book on the vegetation types of Brazil, also used the
term vdrzeafor all periodically flooded forest and igap6 for all permanently flooded
forest. He pointed out the important distinction between "high vfirzea," which is
flooded only for a short period when the rivers crest, and "low vfirzea," which is
flooded for a much longer period. He also clearly drew attention to the differences
in 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 tidal
vdrzea near Belrm and one of the seasonal igap6 on the Rio Negro. The latter
inventory was done by William A. Rodrigues, who used the term vdrzea for the
riverine vegetation of the black-water Rio Negro.
Takeuchi (1962) applied igap6 to forests growing on very low ground with only
a very short dry period, regardless of water type. For example, the area described
by Takeuchi at Lago Janauaca is clearly subject to white-water flooding with many
species of plants that do not grow in association with black-water, and the Rio
Cuieiras area is one of black water with its characteristic vegetation. In Prance
(1975) I also followed the commonest usage of these terms in botanical literature
by defining temporarily flooded areas as vdrzea and permanently flooded ones
The most satisfactory vegetational classification of inundated forest to date is
that 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 along
either black- or clear-water rivers.
Earlier Sioli (1951) had proposed a revised terminology with the term vdrzea
restricted to white-water flooded areas and igap6 for black-water flooded areas.
Irmler (1977) also followed Sioli's terminology and clearly applied vdrzeato forest
flooded by white water and igap6 to black water. In addition, Irmler recognized
28 BRITTONIA [VOL. 31
three types of vdrzea and two of igap6 based on the degree of flooding and the
distribution of the benthic macrofauna. Irmler helped greatly to clarify the differ-
ence between vdrzea and igap6, but did so primarily by differentiating the benthic
fauna 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 clearly
the 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 English
equivalents is obviously confused and there is a need for redefinition of the inundated
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 Amazonia
An important factor in the composition of the inundated forest vegetation is the
water type. There are three main types of water in the rivers of Amazonia. Certain
riverine plants grow only in one water type, mainly because of differences in acidity
and 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 of
alluvium. The Rio Solim6es, a white-water river, has a pH of 6.9-7.4 (Schmidt,
Black waters appear dark blue to black and contain clear water which is stained
dark brown by a colloidal suspension of plant compounds. The black water of
the 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 largest
is 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) gives
the humic contents of the three main Amazon water types as follows:
Rio Negro (black water) 26.6 rag/liter
Rio Solim6es (white water) 14.1 mg/liter
Rio Tapaj6s (clear water) 2.26 mg/liter
Further details about Amazonian water contents are given in the various studies
of the Max Planck LimnologyInstitute in P16n, for example in Anonymous (1972),
Schmidt (1972a, 1972b), Sioli (1965, 1967), and in Williams et al. (1972). It
is obvious that such great differences in pH, nutrients and humic matter will have
an influence on vegetation type, yet current definitions of the flooded forest types
largely ignore the water characters.
The Vegetation Types of Inundated Forest
There are seven main types of vegetation on inundated ground in Amazonia,
five of which are periodically inundated and two of which are permanent swamp
forests. These may be defined both by vegetation cover and by the type of water or
duration of flooding. These seven types of flooded vegetation are defined in the
key below, and the associated vegetation discussed in some detail. The classification
below differs from previous vegetational definitions in that it follows the practice
adopted by limnologists which restricts the term igap6 to black- and clear-water
1979] PRANCE: AMAZONIAN FOREST TYPES 29
Key to the principal types of Amazonian forests subject to inundation
1. Periodically inundated forest.
A. Flooded by regular annual cycles of rivers.
i. White water. 1. SEASONAL VARZEA
ii. Black and clear water. 2. SEASONAL IGAPO
B. Flooded by tidal movements.
i. Salt water. 3. MANGROVE
ii. Fresh water backup. 4. TIDAL VARZEA
C. Flooded by irregular rainfall (flash floods).
5. FLOODPLAIN FOREST
2. Permanently inundated forest.
i. White water. 6. PERMANENT SWAMP FOREST
ii. Black and clear water. 7. PERMANENT IGAPO
Apart from the seven major types of inundated forest distinguished above, there
are 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 widespread
and 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 Allantoma
lineata (Mart. ex Berg) Miers ranges from the upper rlos Orinoco and Negro in
Venezuela to the vicinity of Bel6m. In southern Venezuela in the Rio Negro region
Fi~. 1. Aspect of seasonal vdrzea (swamp) forest, Riozinho, Pardi, Brazil. In flood s.eason
the trees in this photograph will be about 2 meters deep in water.
30 BRITTONIA [VOL. 31
Fro. 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 comparative
ecological 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 TYPES
SOME CHARACTERISTICTREESOF SEASONALV/~RZEAFOREST
Bombax munguba Mart.
Bothriospora corymbosa Hook.
Calycophyllum spruceanum (Benth.) K. Schum.
Carapa guianensis Aubl.*
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.
* Also widespread outside vdrzea.
occurs to find out whether there are any association communities definable in
terms of their vegetation, as Irmler (1977) found in terms of the benthic fauna.
1. Seasonal vfirzea (swamp) forest = Mata de vdrzea
This 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) and
pneumatophores are common. There is considerable variation in the seasonal
vdrzea forest because of the length of the annual flood period. On sloping river
banks the duration of inundation decreases with distance from the river bank. This
is the most extensive and widespread of all types of flooded forest in Amazonia and
occurs along all the major white-water rivers, often extending several kilometers
back from the river bank. The herbaceous zone of the forest is rich in individuals of
Heliconia (Musaceae) and Costus (Zingiberaceae). Some of the many species of
trees characteristic of this forest are listed in Table I. Many of the predominantly
vdrzea species in Brazil are not confined to vdrzea in Amazonian Peru, where the
climate is wetter, or in extra-Amazonian tropical America. Pires (1961) made a
geographic division of the vdrzea into "vdrzea forest of lower Amazonia" and
"vdrzea forest of upper Amazonia." This division is not used here since it is
preferable to wait until there is a firm basis for subdividing the various types of
seasonal swamp forest according to association communities.
2. Tidal v~irzea (swamp) forest = Mata de vdrzea estuario
This forest is flooded and drained twice daily by the tidal movements, because
high tides temporarily block the flow of rivers in the estuarine region and cause
them to flood the adjacent forest. Curiously this more consistently wet type of
forest is very similar to the seasonal vdrzea both in species composition and in
physiognomy. 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. 31
FIG. 3. Black-water igap6, Rio Negro near Manaus, further down river than in Fig. 5 where
there 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 various
vegetational subdivisions. The estuarine areas subject to daily tides are obviously
more swamp-like than land flooded only by spring tides, the latter tending to be
similar to the seasonal vdrzea.
Areas dominated by palms are frequent in the tidal vdrzea as well as the prevalent
mixed forest. The commonest palms, Mauritia flexuosa L.f. and Euterpe oleracea
Mart., often found in pure stands, are also found in other habitats, whereas Raphia
taedigera Mart. and Manicaria saccifera Gaertn. are two abundant species restricted
to tidal areas throughout their range.
Common trees of the tidal vdrzea forests include Virola surinamensis Warb.,
Cedrelinga castanaeformis Ducke, Ceiba pentandra Gaertn. and Mora paraensis
Ducke. One of the most characteristic species of the forest margin and succession
is 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 igap6
This term is restricted here to the forest which is annually flooded by black- or
clear-water rivers. Igap6 usually has sandy soil which sustains a much poorer
vegetation 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 species
and displays xeromorphic adaptations, such as sclerophyllous leaves. The forest is
often interspersed with sandy beaches. There is much less species diversity, and the
trees tend to be low and tortuous. Sclerophyllous leaves are characteristic and
there is a greater number of insects (Adis, 1977). However, denser and physi-
1979] PRANCE: AMAZONIANFOREST TYPES 33
FIG. 4. Black-water igap6, Rio Negro near Manaus. Even at the low-water level there are
shrubs 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, especially
in 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 forest
often descends almost to the low-water level, and consequently some of it has only
a two-month dry period (Figs. 3, 4, 5 & 6). Many species of trees and shrubs are
endemic 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 understory
palms of this forest is Leopoldinia pulchra Mart. (Fig. 5). Another common palm
of igap6 is Mauritia aculeata H.B.K.
SOME CHARACTERISTIC PLANTS OF IGAPO
Aldina latifolia Benth. var. latifolia
Couepia paraensis (Mart. & Zucc.) Benth.
Eugenia inundata DC.*
Eschweilera (lugastrum ) eoriaeeum (DC.) Miers*
Licania apetala (E. Mey.) Fritsch
Macrolobium acaeiae[olium (Benth.) Benth.*
Parkia peetinata (H.B.K.) Benth.
Crudia amazoniea Benth.
Tabebuia barbata (E. Mey.) Sandw.
* Also occur less abundantly in white- or mixed-water areas.
34 BRITTONIA [VOL. 31
FIG. 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 a
more diverse vegetation than the areas flooded for longer periods in Figs. 3 & 4.
4. Mangrove forest = Mangue
Mangrove forest occurs abundantly in the estuarine region of Amazonia in areas
which are flooded daily by brackish water. The mangrove formation is well known
and easily recognized. It is included here only because it is one of the inundated
1979] PRANCE: AMAZONIAN FOREST TYPES 35
forest types of Amazonia. Where it extends into fresh water it is often part of the
succession colonizing newly formed banks, rather than a climax forest type. This
typical 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 mangrove
Rhizophora racemosa G. F. Mey. extends as far upstream as the tides in some
places and thus is not confined to brackish water.
5. Floodplain forest
This term refers to forest that is flash-flooded by irregular rainfall. It exists
mainly in the upper reaches of Amazonia and beside small creeks. Floodplain
forest is subject to flash flooding by heavy rainfall at any time of year rather than
by the regular seasonal flooding of large rivers. It is physiognomically similar to
seasonal vdrzea and shares many of the same species. Where flooding is usually
of short duration only, various species characteristic of terra firme forest also occur.
6. Permanent swamp forest (permanent igap6 and permanent white-water swamp
Permanent swamp forest, on ground that is continuously waterlogged, is rarer
in Amazonia than the periodically flooded forest types. It is often of the "back
swamp" type and occurs behind the main river banks in depressed areas that never
fully drain out in the dry season and that are created by a bank or levee of riverine
alluvium which forms between them and the river. In lower Brazilian Amazonia
the 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 is
restricted to the black- and clear-water areas since the two vegetation types are
quite different. There are very few black-water permanent swamps or permanent
igap6s 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 is
more open than in the vdrzea and the ground flora is rich in Cyperaceae. This type
of swamp forest was termed "igap6 do estudrio" by Pires (1961) and is best referred
to as tidal permanent swamp forest. All the permanent swamp forests of the
Amazon basin proper are fresh-water swamps in the sense of Richards (1952) and
Whitmore (1975), overlying gleyed soil. In the coastal region of the Guianas peat
swamp forest occurs, locally termed pegass swamp. The conditions which lead to
the 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 tropica'
Far East where both kinds occur extensively (Whitmore 1975).
7. Mixed water inundated forests
In the region of Manaus, Brazil, where the large black-water Rio Negro and the
large white-water Rio Solim6es come together, and in other river confluences with
differing water types, the forest falls under the influence of both types of water since
the rivers crest at slightly different times. Another example of this is seen in the
northern part of the Anavilhanas Archipelago in the Rio Negro, where the influenr/
36 BRITTONIA [VOL. 31
Fic. 6. Adventitious rooting is a characteristic of black-water igap6, photographed here
beside the Rio Negro, above Manaus.
of the large white-water river, the Rio Branco, influences the igap6 vegetation of the
Rio Negro. In the northern part of the Anavilhanas the physiognomy of the igap6
is more similar to that of white-water vdrzea.
This brief review of the major types of inundation forest points to the lack of
good data on plant association communities by which to define the various vegeta-
1979] PRANCE: AMAZONIAN FOREST TYPES 37
tion types. There is an obvious need for further study of the inundated forest types
to differentiate the subdivisions of the categories defined here according to their
vegetation and physiognomy rather than by the degree of flooding and type of water.
Recent work in Amazonia has been supported by National Science Foundation
grant 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 for
offering many helpful suggestions.
Adis, J. 1977. Programa mlnimo para anfilises de ecosistemas: Antr6podos terrestres em
florestas 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 et
contribution 5. la connaissance des for~ts de 1'Amazonie 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. Anais
Acad. 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. New
York Bot. Gard.
Irmler, U. 1977. Inundation--Forest types in the vicinity of Manaus. Biogeographica 8:
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 of
Central Amazonia along the new road Manaus-Caracaral. Amazoniana 3(2): 199-207.
1972b. Amounts of suspended and dissolved substances in the middle reaches of
the 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):
1965. Bemerkungen zur Typologie amazonischer Fliisse. Amazoniana 1: 74-83.
1967. Studies in Amazonian waters. Atas do Simp6sio s6bre a Biota Amaz6nica 3:
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. 31
Whitmore, T. C. 1975. Tropical rain forests of the Far East. Clarendon Press, Oxford.
Williams, W. A., R. S. Loomis & P. T. Alvim. 1972. Environments of evergreen rain forests
of the lower Rio Negro, Brasil. Tropical Ecology 13: 65-78.
Polygonaceae (Buckwheat Family) of New York State. Richard S. Mitchell and
J. Kenneth Dean. Contributions to a Flora of New York State I, edited by
Richard S. Mitchell. Bulletin 431, 79 pp. + index, illus., maps. New York
State Museum, Albany. 1978. $2.50.
This account of the Polygonaceae of New York state, floristic in scope but
essentially monographic in depth and originality, is the first contribution to a state
flora which, when completed in the same style, promises to become a classic in
its field. The Buckwheat family is represented in New York by the common
rhubarb, 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 in
the area. At the outset the authors have tackled a group notorious for its com-
plexity, which involves in Rumex hybridization and polyploidy and in Polygonum
the vexed status of the amphibious species and of the cosmopolitan weeds. It is
an 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 read
and to handle. It consists of a short preface, the floristic substance, appendices
listing fungi and some insects associated with Polygonaceae in New York, an
impressive bibliography, and an index to Latin names. The descriptive matter
includes a detailed description of each genus, keys to the species, and for each of
these an original account, an illustration (habit-sketch with significant organs
appropriately enlarged), a map of dispersal in the state, followed by paragraphs on
taxonomic variation and economic uses. A box paragraph immediately following
the name of each species encapsulates several of its leading features: common
names, taxonomic synonyms, protolog, geographic origin, habitat, habit of growth
and duration, season of flowering, and dispersal outside the state. A peculiarity of
the generic and specific descriptions is the inversion of the traditional order of
presentation 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 virtue
of this inversion is to place emphasis on the organs of production which furnish
the basis of classification. While the evaluation of the species is conservative,
care has been taken to note internal complexity and unsolved problems; no dust
is swept under the rug. The discussion of Polygonum amphibium, clearly derived
from original observations of a sort detectable throughout the contribution, is
Dr. Mitchell, Dr. Dean, the council of the Flora Committee and the State
Museum 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 popular
accessibility, a textbook that will be used and enjoyed no less by technical botanists
than by plain people. We look forward with anticipation to further contributions
and ultimately to a comprehensive account of New York's rich and varied flora.
--RUPERT C. BARNEBY, New York Botanical Garden, Bronx, NY 10458.