VI LATIN AMERICAN BOTANICAL CONGRESS
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IAWA Journal, Val. 16 (1), 1995: 24-31
VI LATIN AMERICAN BOTANICAL CONGRESS
October 6 & 7, 1994, Mar deI Plata, Argentina
Conveners: Vera T. Rauber Coradin, Stella Maris Rivera, Fidel Roig and Aracely V. Gomes
ABSTRACTS OF PAPERS AND POSTERS
VERONICA ANGYALOSSY -ALFONSO* & REGIS B. MILLER * *, *Departemento de Botänica, Instituto
de Biociencias, USP, CP 11461, CEP 05422-970, Säo Paulo-SP, Brazil; **Center for Wood
Anatomy Research, USDA, Forest Service, Forest Products Laboratory, One Gifford Pinchot
Drive, Madison, Wisconsin 53705-2398, USA. - Wood and bark anatomy of Swartzia
Sehreber: Taxonomie eonsiderations.
The wood and bark anatomy of Swartzia is analysed in detail, with the purpose to group the
species. Fifty-three species and varieties were studied of Brazilian Swartzia and 7 other genera
of tribe Swartziae (Bocoa, Aldina, Cordyla, Mildbraediodendron, Lecoitea, Zollemia, Can-
doleodendron). For the wood of Swartzia the characters with major diagnostic value are: tangential
diameter of the intervessel pits; ray width (number of cells); storied rays; frequency of rays;
vessel diameter. A Single Linkage Cluster Analysis was done with these five characters for the
Swartzia species and the other genera of the tribe. This analysis indicated that four basic groups
exist as folIows: Benthamiana, Laxiflora, Arborescens and Simplex. Analysis of the bark characters
also produces the same grouping as did the wood anatomy. Two ofthe groups, Benthamiana and
Laxiflora, match those in the classification proposed by Cowan (1967).
JUAN CARLOS ARAVENA*, ANTONIO LARA * * & RICARDO VILLALBA ** *, *Laboratorio de Botanica,
Facultad de Ciencias, Universidad de Chile, Santiago, Chile; **Instituto de Silvicultura,
Universidad Austral de Chile, Valdivia, Chile; ***Laboratorio de Dendrocronologia, CRICYT,
Mendoza, Argentina. - Fitzroya cupressoides tree-ring ehronologies from southem Chile
and Argentina.
Fitzroya cupressoides (alerce) is a native Chilean conifer, endemie to the southern temperate
rain forests of Chile and adjaeent areas in Argentina. Reaehing ages of up to 3,600 years, aleree
tree-ring width analyses are a valuable tool for studying paleoenvironmental records. The objec-
tive of this project was to broaden the eoverage of alerce dendroehronologieal samples along its
geographie distribution, and to correlate tree-ring widths among and between stations: Los Pabilos
and Pichihue in the Cordillera de la Costa; Bosque Neumann, along the Valle Longitudinal; and
Lago Inexplorado, Lenea, and Rio Aleree, in the Andean Cordillera. In general, reeords at these
sites show medium to high eorrelations. This implies that the growth pattern of this speeies
corresponds largely with regional environmental patterns. However, reeords from sites along
the Andes and the Cordillera de la Costa correlate better among themselves than with eaeh other.
SIDAN DE BAEZ, OLGA MYRIAM BAEZ* & MIGUEL ADOLFO**, *Fundaei6n Miguel Lillo; **Fac.
de Cs. Naturales einst. Miguel Lillo U.N.T. San Miguel de Tueuman, Tueuman, Argentina. -
The applieation of dendroehronology to the study of the dynamies of erosion.
The eurrent investigation was earried out at the base of the mountain range 'Sierra de San
Javier' (Tueuman) in a small drainage basin encompassing an area of 10 ha. Due to the agrieultural
aetivity of this area since the beginning of the eentury, a system of gullies ('carcavas') has
developed within the old production areas. The objeetive of this research was to study the dynamics
of erosion by gulling ('earcavamiento'), using indieations in the vegetation that allowed us to
date this proeess. These indieators included the inclination and/ or the subsequent fall of
the trees, the presenee of vertieal shoots, the eurvature of the trunk, harp-shaped trees, etc. The
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methodology used involved, first, the inspection and mapping of the area, followed by the selection
of individuals within the eroded sector that could provide data about the stability or instability of
various sites, which involved the use of special methods and interpretations. The sampies were
taken out using an increment borer and cross sections. The data taken (tension wood, decreased
growth, etc.) were interpreted according to Alestalo (1971). With respect to dynamics of erosion
in the sector, the results showed a total volume of soilloss of approximately 279 m 3 . At one of
the gully-head ('cabecera') we estimated a loss of 6.5 m 3 of soil in 18 years (tension wood in
Cupania vemalia Camb). Moreover we detected the occurrence of an important erosion event in
1981 which produced the inclination and subsequent fall of trees in the low zones (Celtis iguanea
(Jacq.) Sarg.) and an extension of the gullY ('carcava'). Significant broadenings of the gully by
means of lateral collapses with the addition of material, were produced before 1983 (currenty
colonized by lO-year-old Psychotria carthagenensis Jacq.). In general the layer of soil affected
by creeping varies from 0.30 to 1.10 m in thickness (roots of Phoebe porphyria (Griseb.) Mez).
STEPHEN H. BULLOCK, Centro de Investigaci6n Cientifica y Educaci6n Superior de Ensenada
A. P. 2732, 22800 Ensenada, Baja California, Mexico. - Estimation of size-age relationships
for live species of very dry tropical forest.
Estimates of tree ages are necessary for understanding forest dynamics. In tropical forests
age estimates usually must depend on extrapolation from repeated measurements of girth. Five
species contrasting in phylogeny, anatomy, physiology, reproduction, density and 'successional'
niche have been under study for periods of 5 -11 years in deciduous forest in western Mexico
(with c. 700 mm annual precipitation). Total increments were used to simulate 1000 growth
trajectories per species by repeated random use of observed increments of trees of similar size
(protocol of Lieberman & Lieberman). The median growth trajectory neared maximum size at
about the age of 200 years in Jacaratia mexicana (Caricaceae), 90 in Cochlospermum vitifo-
lium (Cochlospermaceae), 50 in Cnidoscolus spinosus (Euphorbiaceae), and 150 in Cordia
elaeagnoides (Boraginaceae). Growth of Forchhammeria pallida (Capparaceae) was so slow
and constant that no asymptote was obvious by the age of 200 years. Of course, most trees die
when much smaller. The effect of the duration of the study on the age-size relation was examined
for Jacaratia: no conspicuous changes occurred in the median trajectory among intervals of 5,
7,9, and 11 years. This species has a density of 0.16, reaches diameters far exceeding the other
species, and may live as long as Forchhammeria (density 0.82) or Cordia (0.88). However,
confidence limits (95%) for Jacaratia over 11 years were wide; maximum size may be approached
in just 70 years with the Lieberman protocol. Thus, variations in growth rate are too large to
allow ages to be confidently assigned to individuals.
CATIA H. CALLADO* & CEcIUA GONC;:ALVES COSTA **, *Universidade Federal do Rio de Janei-
ro /Jardim Botanico do Rio de Janeiro, Brazil; **Jardim Botanico do Rio de Janeiro, Brazil.-
Wood anatomy of Beilschmiedia Nees (Lauraceae).
The wood anatomy was studied of Beilschmiedia brasiliensis (Kost.) Kost., B. rigida (Mez)
Kost. and B. taubertiana (Schw. & Mez) Kost. Material was collected from: Munidpio de Tefe-
AM, Reserva Eco16gica de Macae de Lima-RJ and Estac,:ao Eco16gica do Parafso-RJ, and it was
processed using the usual technique of light microscopy. These species have diffuse-porous
wood; simple perforation plates; alternate intervessel pits; paratracheal parenchyma; uniseriate
and multiseriate rays; storied fibres with inconspicuously bordered pits (2 1JIIl) on the radial
walls. Differences are found in: B. brasiliensis: silica bodies present in ray cells and oil cells
frequently associated with axial parenchyma; B. rigida: without inorganic inclusions; mucilage
cells present; B. taubertiana: calcium oxalate crystal sand in ray cells and abundant silica bodies
in the radial and axial parenchyma cells.
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- - - - - - -----
GREGÖRIO CECCANTINI, Departemento de Botänica, Instituto de Biociencias, Universidade de
Säo Paulo, CP 1146, Sao Paulo-SP, Brazil. - A new technique for observation of perforated
ray cells.
The technique used is based on paleopalynological methods, It provides an easy way for
finding perforated ray cells (PRC). Maceration was prepared by Franklin's method. Staining
was done with astra-blue and/or safranin. The length of cell elements was measured and the
cells were suspended in water by agitation. The suspension was passed through a sieve which
pores were smaller than the average length of vessel elements and fibres. Each group of cells
(fibres + vessel elementslPRSs + normal parenchymatous ray cells) was centrifuged in increasing
ethanol concentrations, until complete dehydration was achieved. The preparation was dropped
on a glass slide, with permanent mounting media, or on a SEM stub. It was possible to find about
10 PRC/cm 2 • The slide looked very homogeneous and many PRCs were easily found between
the normal ray cells. Slides with only vessel elements and fibres remaining after the separation
process were useful for the study of perforation plates.
CECILIA G. COSTA*, VERA T. RAUBER CORADIN** & CLÄUDIA M. CZARNESKI***, *LPF/Jar-
dirn Botänico do Rio de Janeiro/Bolsista CNPq; ** LPF/Laboratorio de Produtas Florestaisl
IBAMA, Brasilia, Brasil; ***Bolsista CNPq. - Bark anatomy of Leguminosae of cerrado
and gallery forest.
Studies on bark anatomy of Leguminosae of Cerrado and Gallery Forest of DF-Brazil aim
to contribute to improvement of classification within the family. U sual techniques in the study of
bark antomy were used. Terminology followed Trockenbrodt (1989). Nine species of
Caesalpinioideae and 8 species of Mimosoideae were studied. Gelatinous fibres and prismatic
crystal chains in axial parenchyma cells were observed in the analyzed species. Mimosoideae
are characterized by homocellular rays in the phloem; these rays are uniseriate to 1-3 cells
wide, and 3-5 cells in height. Other features such as type of sieve plates; number of sieve areas
per plate; dimension and arrangement of lateral sieve areas; arrangement of sclereids; contents
of sclereids; ray structure and presence of secretory cells, are diagnostic features used in keying
out species in both subfamilies.
MIGUEL GOMEZ, ISABEL TORREALBA & GLORIA MONTENEGRO, Departamento de Ecologfa, Fa-
cultad de Ciencias Biol6gicas, Pontificia Universidad Cat6lica de Chile, Santiago, Chile. -
Anatomical features of the wood of two species of Nothofagus.
In Chile there are 9 species of Nothofagus dominant in areas of temperate forests of the
southern region, between the 33° and 56° Southern latitude. The heavy use of these two species
as wood for houses and furniture as weil as for charcoal and firewood, plus the replacement of
their native areas with the introduced species Pinus radiata has caused some of these species to
be included within the List of Endangered Species that appears in the Red Book of Terrestrial
Chilean Flora. Nothofagus alessandri is an endangered species, while N. obliqua, N. glauca, N.
dombeyi, N. leonii and N. alpina are vulnerables. With this in mind, we thought analysis of the
biology of some of these species was urgently needed, and especially the wood anatomy and the
characteristics responsible for the quality of the wood. This was achieved by a thorough and
detailed analysis of the fibre quality and of the xylem vessels, and their distribution. The results
showed that both species have similar anatomical characters. Annual rings are visible. The wood
is ring-porous and has numerous isolated vessels and vessels in radial clusters of two or more
cells with a narrow diameter (about 20 to 100 lJII1 wide and up to l.l mm long). The rays are
heterocellular, 3 to 33 cells high, uniseriate in N. dombeyi and frequently biseriate in N. obliqua.
The fibres are short, less than 1.4 mm long. In the heartwood, tyloses and tannin deposition
occurs frequently, characteristics responsible for the high durability of the wood.
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PAULA M. HERMANN, Dept. de Biologfa, Universidad Nacional deI Sur, Bahfa Blanca, Argentina.
- Identification of wood from 'La Olla', an archaeological site in Monte Hermoso, Buenos
Aires.
The archaeological site 'La Olla' is located 6 km W of Monte Hermoso (38 0 57' 47" lat. S
and 61 0 22' 48" long. W) at the beach and under water. It was uncovered in two phases: 1984 and
1993. In the lauer one, a fragment of wood, 15 cm long and 2 cm in diameter, was recovered
from the deposits dated c. 7,000 years before present. Cross- and longitudinal sections showed
semi-ring-porous wood with a high number of solitary to short multiple pores with alternate
bordered pits with oblong apertures, numerous storied, uniseriate - rarely biseriate - rays, and
confluent parenchyma in interrupted bands. These peculiarities characterize the wood of GeojJroea
decorticans (Gill. ex H. et A.) Burkart (Chafiar).
HELGA LINDORF, Centro de Botanica Tropical, Apartado 20513, Caracas 1020, Venezuela. -
Correlation between wood structure and other plant features in species from a dry forest
of Venezuela.
When wood anatomy is studied in plants from arid environments, the degree of xeromorphism
that would be predicted is not always observed. The ability of trees to survive in water stressed
situations may be determined by adaptations in: foliar structure, phenology, root system depth,
hydraulic architecture, special photosynthetic pathways, etc. The correlations between wood
anatomy and the other characteristics is analysed in this paper. According to some authors
deciduousness can mitigate or 'buffer' the development of xeromorphic specializations in the
wood, but in the forest the majority of the deciduous species showed a remarkable xeromorphism
in their wood. Due to the predominance of deciduous species a high degree of foliar xeromorphism
was not observed. However, in some species with xeromorphic leaves a lower degree of
xermorphism in the wood was noted. In several of the species studied both leaf and wood show
xeromorphic features. In other species root depth, succulence, assimilating sterns or CAM meta-
bolism seem to buffer development of xeromorphic characters in the wood so that it appeared
somewhat mesomorphic.
CLAUDIA LUIZON DIAS LEME* & VERONICA ANGYALOSsY-ALFONSO**, *FAPESP GRANT;
**Departemento de Botänica, Instituto de Biociencias, USP, CP 11461, CEP 05422-970, Sao
Paulo-SP, Brazil. - Wood anatomy and stern and root of five Euphorbiaceae species.
In the present study we made a comparison between the wood anatomy of root and stern of
Alchomea sidifolia Muell. Arg., A. triplinerva (Spreng) Muell. Arg., Croton floribundus Spreng.,
Sapium glandulatum (Vell.) Pax and Sebastiana serrata (Baill.) Muell. Arg., all species from the
Atlantic forest. The woods show in common: axial parenchyma diffuse and diffuse-in-aggregates,
heterocellular rays and fibres thick-walled, with bordered pits. There are no significant differences
between these. However, the following diagnostic characteristics can help to separate the ge-
nera: ray width (number of cells), vessel diameter, intervessel pits diameter, ray canals and silica
bodies. The results show that, for these species, we can use root anatomy to identify the species.
This study also gave details about the development of transpierced fibres and disjunctive cells.
NORA E. MARTIJENA, Centro de Investigaci6n Cientifica y Educaci6n Superior de Ensenada
A. P. 2732, 22800 Ensenada, Baja California, Mexico. - Dendrochronology in Mexico.
In Mexico, tree-ring chronologies currently number 35, including one based on archaeological
collections. Most fieldwork was concentrated in the early 1970's. In search of good climatic
signals, expeditions were limited almost exclusively to arid and temperate regions of the Sierra
Madre Occidental and the mountains ofBaja California. In the last decade only eight chronologies
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have been derived or are in progress; some of these represent a southward expansion of the area
studied in mountain climates of the Transverse Neovolcanic ranges and the Sierra Madre dei Sur
(Oaxaca). The amplitude of the chronologies is variable. Some reach prehispanic times (initial
year before 1500), while others cover only part of the last century. The 20 species used are
exclusively conifers, of the genera Pseudotsuga, Pinus, Abies and Calocedrus. In hot tropical
climates, little dendrochronology has been done in spite of extensive regions with a prolonged
annual dry season. Two recent studies show significant relations between some components of
the precipitation regime and growth of some species in tropical dry forest. Preliminary analyses
of some species from the Pacific coast also suggest the existence of annual growth rings. In the
extensive xerophytic shrubland regions of Mexico, there have been no applications of den-
drochronology, although some species of Californian chaparral are known to form annual rings.
The purposes of studies using dendrochonology has diversified in recent years, although the
majority are still for the reconstruction of climatic characteristics (e. g. ENSO and ocean surface
temperature). Some new chronologies have been developed on the basis of ecological and
silvicultural interests, e. g. contrasting fire histories under different management regimes, and
the effects of air pollution on growth. However, the network of chronologies and the current
effort are smalI, considering the possibilities, their economic importance and rapid deforestation.
H.R.L. PUGIALLI, C.P. BARROS, C.H. CALLADO, M. CUNHA, c.G. COSTA & O. MARQUETTE,
Jardim Botänico do Rio de Janeiro, Brazil. - Wood antomy of Atlantic rain forest species.
The project 'Plant Anatomy of Atlantic Rain Forest Species' has been developed by the
Botanic Garden of Rio de Janeiro. The study concerns wood anatomy of the 13 species that have
a major value importance index and come from the Ecological Reserve ofMacae de Lima, Nova
Friburgo, Rio de Janeiro. They are: Beilschmiedia rigida (Mez) Kosterm., Ocotea divaricata
(Nees) Mez, Leandra breviflora Cong., Merianea robusta Cong., Mollinedia micrantha Tul., M.
gilgiana Perk., M. salicifolia Perk., Myrcia pulsipetala Miq., Plinia martinellii G.M. Barroso &
M. Peron, Coussareafriburguensis M. Gomes, Psychotria suterella Muell. Arg., P. velloziano
Benth. and Ormosia sp. nov. The material was processed using the usual techniques for light
microscopy and scanning electron microscopy. The aims of this study of the wood anatomy
were to find adaptations of these species to the environment and give support to taxonomy, to
establish species relationship, to increase knowledge of species in danger of extinction and to
start a wood collection in the Botanic Garden ofRio de Janeiro of sampies from the Atlantic rain
forest.
FIDEL A. RorG J. & FIDEL A. RorG, IANIGLA-IADIZA (CRICYT -CONICET), Mendoza, Argen-
tina. - Evidences of fires in the Patagonia Araucaria forests.
Dendrochronological and phytosociological studies were completed on fire-affected
Araucaria forests of the Carico-Araucarietum Oberd. association in the Icalma area, northern
Patagonia (Argentina-Chile frontier). Affected areas showed a dramatic change in plant
composition and a simplified forest structure in comparison with unburnt areas. Four strata were
recognizable in unburnt areas, the upper one (25 - 30 m) being composed of Araucaria araucana,
several Nothofagus species, Lomatia obliqua and Austrocedrus chilensis. In burnt areas only
two strata were recognizable, the upper one being represented by relictual giant Araucaria trees
and the lower one by shrubby species, including young Araucaria individuals. There were 50%
fewer species in unburnt areas, compared with burnt areas. Fire scarring, the most common
evidence of forest fire, is a rather difficult character to see in fire-surviving Araucaria individ-
uals. However, the older the Araucaria tree, the thicker the bark layer becomes, providing an
effective protection against fires of moderate intensity. Therefore, repeated fire-induced thinning
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and ash fertilization often influence the growth characteristics of the surviving trees, and, in
many cases, may be more easily detected than fire scars. To prove this hypothesis tree-ring
width and density parameters were analysed radiodensitometrically for several tree cores collected
from fire-affected and unaffected sites. A large growth ring increment was observed around the
1940's through the analysis of tree-ring series of trees several hundred years old. The long-term
anomaly was not detected in those Araucaria trees growing in sites very close to affected areas.
This out-of-phase fluctuation was primarily interpreted as a subsequent growth response to a
fire event. Maximum and minimum density variables did not show noticeable modifications for
trees in affected sites. Plant dynamics and climatic inferences also supply evidence of a fire
event at this time. A dense Araucaria forest regeneration stratum was established since the
1950's, surrounding the older mother trees. A young tree concentration of this kind was not
observed in unaffected sites. Instrumental and dendroclimatic reconstructions of temperature
show a peak during the beginning of the 1940's, especially in the Icalma area. The observed
1943/44 growth depression and the growth release abruptly starting in 1946, suggest a fire event
centred in the years 1944/45. Through this study, the combined climatic, phytosociological,
dendrochronologieal, and wood anatomy characteristics have proved the potential to date ex-
treme environmental disturbance (especially fires) in the Patagonia Araucaria forests.
PATRICIA SOPPIATH* & VERONICA ANGYALOSSY -ALFONSO**, *FAPESP GRANT; **Departemen-
to de Botänica, Instituto de Biociencias, USP, CP 11461, CEP 05422-970, Säo Paulo-SP, Brazil.
- Wood and bark anatomy or live species or Myrtaceae.
The present work is a comparative study of wood and bark antomy of five species of
Myrtaceae: Eugenia cerasiflora Miq., E. uniflora L., Myrciariajaboticaba (Vell.) Berg, Myrcia
cv. glabra (Berg) Legr. and M. longipes Maersk. The wood anatomy of the species is very
similar, but bark anatomy shows great variation. Interspecific differences in wood anatomy are:
type ofaxial parenchyma, presence of crystals, vessel diameter and frequency, and ray widths.
The bark anatomy is highly variable in terms of type of sclerenchyma cells and type and number
of periderms. Since there are few studies in bark and wood anatomy on Brazilian Myrtaceae, it
is necessary to demonstrate the importance of using bark anatomy in conjunction with wood
anatomy as a means of helping in problems of identification in this family.
TERESA TERRAZAS, Department ofBotany, University ofNorth Carolina, Chapel Hill, NC 27599-
3280, USA. - Ecological wood anatomy trends in the Anacardiaceae.
The Anacardiaceae have a wide geographie distribution. Anacardiaceous taxa occur be-
tween latitudes 0° to more than 40° both N and S, and 0-2,500 m elevation. Habits and phenol-
ogies are also diverse. These diversities provide a system suitable for examination of trends in
ecological wood anatomy as proposed by Carlquist, Baas, and Rury & Dickison. Nearly 700
sampies belonging to 63 genera were studied and measured with the main objective of
understanding the wood anatomical character variation from an ecological perspective. Multi-
ple regression analyses showed that two to four variables (latitude, altitude, moisture availability,
phenology, and habit) explained a percentage of the total variance of quantitative wood anatomical
characters. The results suggest that habit and phenology have a major effect on the vessel
morphology, and moisture availability on fibre wall thickness and phenology on ray width. In
addition, a 't' -test showed statistically significant differences in four wood characters between
diffuse and ring-porous woods. Porosity type is mainly explained by latitude. In sampIes that are
diffuse-porous, there is a positive correlation between plant size and vessel element length,
suggesting a strong allometric trend. The decrease in plant size is correlated with adaptations to
dry or temperate habitats where seasonality is strong.
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MARIO TOMAZELLO FILHO* & NARCISO DA SILVA CARDOSO**, *Departemento de Ciencias
Florestais, ESALQ/USP, Caixa Postal 09,13418-900, Piracicaba, Sao Paulo, Brazil; **Instituto
de Technologia da Amazönia, Manaus, AM, Brazil. - Wood formation and growth ring
characteristics of teak (Tectona grandis L. f., Verbenaceae).
Evaluation of phenological stages and cambial activity of trees of a teak plantation in
Piracicaba-SP, Brazil were conducted weekly and related to the climatic variables, during a
period of 24 months. The results showed that teak trees present distinct phenological phases:
leaf fall during the dry season (November) and developmentlexpansion of leaves during the
rainy season (January); flowering beg ins with the rainy and warm season (January-February);
fruit set takes place during the rainy period (end of May-through November). The cambial
activity was related with phenological phases: periods ofhigher cambial activity were coincident
with leaf development and expansion (beginning of December, rainy-high temperature season)
and lower cambial activity coincided with the leaf abscission period (September, dry-Iower
temperature season). The growth rings were examined, both macro- and microscopically and
using the X-ray microdensitometry technique. The variation ofthe anatomical structure ofxylem
and growth rings were described and tree age was determined by densitometry. The application
of these results in tropical tree dendrochronology, using teak as a model, is discussed.
MARIO TOMAZELLO FILHO, Departemento de Ciencias Florestais, ESALQIUSP, Caixa Postal
09, 13418-900, Piracicaba, Sao Paulo, Brazil. - Dendrochronology in Brazil - current
situation and perspectives.
Dendrochronology is a science of dating tree rings including the information contained in
their structure and applying it to the reconstruction of previous events. It is arecent science in
Brazil. The first growth ring analysis was done with Auracaria angustifolia, parana-pine, a native
conifer in Brazilian temperate regions, and later with other introduced conifer species. Basic
studies are, however, necessary to determine the seasonality of cambial activity and age
determination. Research has been conducted in tropical and subtropical forests, including flooded
areas, using tree species of riparian and other forest types. Alvim (1964) observed that 35% of
the woods examined from the Amazon forest form distinct growth rings and 22% form slightly
marked growth rings, showing the potential use of dendrochronological studies for tropical trees.
In the present paper the main research results are discussed and the potential tree families for
dendrochronological studies suggested, based on their phenology and wood structure. Other
aspects related to equipment development, inclusion of the theme for undergraduate and graduate
programs, Brazilian literature, etc. are also proposed. Special emphasis is given to the development
of international research projects involving different Latin American coutries and others with
more tradition, and creation of the Institute of Dendrochronology in Brazil.
MARfA E. VIDELA & EA. ROIG, Facultad Ciencias Agrarias/UNC - IANIGLA (CRICYT-
CONICET), Mendoza, Argentina. - Wood anatomy of montane shrubby species from
Mendoza, Argentina.
This paper concerns a study of the wood anatomy of 30 species belonging to 15 families.
The study area comprises the dry, montane environment of the Argentine central Andes, at 30° S
latitude with a continental climate. Wood anatomy descriptions are according the IAWA
terminology. A phenetic cluster analysis was carried out to find which characters have diagnostic
value to separate species. Chiefly, 22 qualitative character states were used. Five groups can be
recognized: I: species having unusual wood owing to included phloem (Nyctaginaceae and
Chenopodiaceae); II: exclusively libriform fibres (some species ofCompositae and Leguminosae,
Labiatae and Anacardiaceae); II1: exclusively paratracheal parenchyma and the presence of
aggregated rays (Compositae, Ephedraceae and Umbelliferae); IV: spiral thickening in vessel
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walls, axial parenchyma scarce and fibre walls thin to thick (Solanaceae, Oleaceae, Rosaceae,
Polygalaceae, Sapindaceae and Verbenaceae); V-vessels without spiral thickenings, fibres very
thick-walled, abundant axial parenchyma and crystals (Leguminosae and Zygophyllaceae). The
solitary vessel character links groups IV and V. General common characters are simple perforation
plates, intervessel pits of medium size, absence of septate fibres and heterocellular rays. Ecological
implications are discussed. The results are combined with a classical dichotomic key.
PABLO E. VILLAGRA, IADIZA (CRICYT-CONICET), Mendoza, Argentina. - Wood structure
of Prosopis alpataco Phi!. and P. argentina Burk. and their possible links with different
edaphic characteristics.
Prosopis is a genus of great economic and floristic importance in Argentina. Two species of
different ecology were considered in this work: P. argentina, psammophilous and with a reduced
distribution in the mid-west of Argentina and P. alpataco, growing in clayey soils, somewhat
salty and liable to be flooded. Prosopis alpataco has a partly overlapping distribution, but is
more widely distributed than the former. Both are shrubs of 1- 2 m height. The aim of this work
is to determine whether the wood structure shows adaptations to different edaphic conditions.
Both species have highly similar woods. The growth rings are differentiated by the presence of
marginal parenchyma and differences in the vessel diameter between latewood and earlywood.
Theyare semi-ring-porous. Perforation plates are simple and intervascular pits are alternate and
small. Axial parenchyma is confluent paratracheal, aliform and vasicentric. Fibres are libriform
and thick-walled. Rays are heterogeneous and homocellular. According to Carlquist's categories,
these species show characteristics ranging from xero- to mesomorphic. The vessel elements are
short and the diameter has abimodal distribution. Nevertheless, P. alpataco has a greater
proportion of solitary and wide vessels, while P. argentina has a greater proportion of narrow
vessels, as weil as vessels grouped in clusters and a greater number of vessels per mm 2. These
differences are statistically significant. The wood structure in P. argentina suggests the
development of a hydraulic safety system which is more effective than that of P. alpataco. This
could be related to the fact that P. argentina is a plant that grows in dunes, where the probability
of droughts is extremely high. Prosopis alpataco reaches the phreatic water, achieving a relative
independence from the hydrological variations of the upper soillayers. Finally, a greater proportion
of gelatinous fibres in P. argentina could be related with the stern movement provoked by the
dunes' activity.
BEN J. H. TER WELLE, Utrecht University, Herbarium Division, Heidelberglaan 2, 3584 CS Utrecht,
The Netherlands. - Wood anatomy of neotropical species of Juniperus (Cupressaceae).
Juniperus, with about 60 species, has a wide distribution ranging from the Northern Arctic
region to the Tropics. In the Neotropics the distribution is restricted to the Southern USA, the
Caribbean and the western part of Central America. Wood sampies of 18 species (24 specimens)
were studied. Most sampies are from Mexico and the USA, but also from Guatemala and several
Caribbean islands. All material has been made available by R.P. Adams. Growth rings are distinct,
the number per mm is very variable, from 0.1-5.5. Tracheids have uniseriate rows of bordered
pits, with a diameter of 10-13(-16) 1JIIl, and apertures of 2-4(-5) 1JIIl. Rays are homogeneous,
4-9 per mm. The rays are generally uniseriate, and occasionally also biseriate. Height: rarely
over 10 cells, commonly 1-4 cells. Cross-field pits (1-)2-4(-5) per cross-field, cupressoid.
Parenchyma is usually abundant throughout the growth rings and often arranged in tangential
zones. The horizontal and tangential walls are pitted, often nodular. Conclusions: The wood
anatomy of the Neotropical species of Juniperus is very homogeneous. Differences are only
found in quantitative data, but cannot be used to separate species, as the variation within the
species is greater than between species.
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