Tree species diversity and forest structure in relation to microtopography in a tropical freshwater swamp forest in French Guiana

Diversity of tree association and forest structure were analysed in relation to microtopography and flooding intensity in a tropical freshwater swamp forest in the Sinnamary river basin, French Guiana. A 530-m-long vegetation transect was established through a hummock-hollow terrain. Nine 10 m× 50 m sample plots, perpendicular to the main transect, were located so that each was as microtopographically uniform as possible. Trees with dbh (diameter at 1.3 m) 10 cm were censused in all plots and trees with 2 cm dbh < 10 cm in three plots. Sixty tree species belonging to 39 genera and 30 families were recorded. The study area was divided into low and high sites according to microtopography and flooding intensity. According to the Czekanowski similarity matrix, the tree association in low, most frequently flooded, sites differed from that in the high sites under intermediate or low flooding intensity. The low sites had higher stand density and lower species richness than the high sites. Trees with dbh 10 cm in low sites were small and stand basal area (SBA) was about the same in low (69.6 m² ha^–1) and high (64.3 m² ha^–1) sites. The low areas were dominated by Pterocarpus officinalis (38% of stems with dbh 10 cm and 36% of SBA) and Malouetia tamaquarina (26 and 15%). Diospyros guianensis (13.4% of stems with dbh 10 cm and 6.1% of SBA), a Caraipa sp. (14.0 and 7.9%), Lecythis corrugata (6.6 and 3.5%) and emergent Caryocar microcarpum (0.9 and 13.9%) were abundant in high sites. Nodulated legume trees, P. officinalis, Hydrochorea corymbosa and Inga disticha, comprised 44% of stems in the low sites. The abundant nodulation suggests that symbiotic dinitrogen fixation may be an adaptation to N-depleted waterlogged soils. Other adaptive responses were litter accumulation between the buttresses of P. officinalis, which formed hummocks above surface water, and clonal growth habit of M. tamaquarina, which resulted in formation of monospecific groves in low sites.     

The diversity of 15 ha of lowland mixed dipterocarp forest, Central Kalimantan

Fifteen hectares of primary forest in Central Kalimantan were enumerated and all trees 10 cm dbh tagged and identified to species as far as possible. Tree density, relative abundance of families and species diversity were calculated, as was a mean additive species/area curve for 1 ha and a species/area curve for all 15 ha. The Jaccard index of similarity was also calculated for the 15 plots. The 15 ha enumerated contain 8771 trees with a dbh of 10 cm, belonging to 1298 morphospecies in 56 families. On average a single plot had 583 trees and 205 species. These figures are within the upper range of species diversity for the Malesian region as a whole. Dipterocarpaceae make up 14% of all trees in the plots, closely followed by Euphorbiaceae with 13%. A surprisingly low coefficient of similarity is found between the plots, the lowest being 3% and the highest 30%. Species/area curve construction showed that the asymptote is not reached in any of the 1 ha plots or when the 15 plots are added together.     

Structure,composition and species diversity in an altitude-substrate matrix of rain forest tree communities on Mount Kinabalu,Borneo

We studied forest structure, composition and tree species diversity of eight plots in an environmental matrix of four altitudes (700, 1700, 2700 and 3100 m) and two types of geological substrates (ultrabasic and non-ultrabasic rocks) on Mount Kinabalu, Borneo. On both substrate series, forest stature, mean leaf area and tree species diversity (both 4.8 cm and 10 cm diameter at breast height [dbh]) decreased with altitude. The two forests on the different substrate series were similar at 700 m in structure, generic and familial composition and tree species diversity, but became dissimilar with increasing altitude. The decline in stature with altitude was steeper on the ultrabasic substrates than on the non-ultrabasic substrates, and tree species diversity was generally lower on ultrabasic substrates than on non-ultrabasic substrates at 1700 m. The forests on non-ultrabasic substrates at higher altitudes and those on ultrabasic substrates at the lower altitudes were similar in dbh versus tree height allometry, mean leaf area, and generic and familial composition at 1700 m. These contrasting patterns in forest structure and composition between the two substrate series suggested that altitudinal change was compressed on the ultrabasic substrates compared to the non-ultrabasic substrates. Tree species diversity was correlated with maximum tree height and estimated aboveground biomass, but was not with basal area, among the eight study sites. We suggest that forests with higher tree species diversity are characterized by greater biomass allocation to height growth relative to trunk diameter growth under more productive environment than forests with lower tree species diversity.     

Contribution of tree species to the biodiversity of a 1ha Old World rainforest in Brunei, Borneo

Tree biodiversity data is presented for a 1-ha permanent study plot on a low slope position of the Kuala Belalong valley in Temburong District, Brunei, Borneo. This is the first study in the region to document the tree flora of a low slope. All trees 5cm at 1.3m were mapped, measurements of dbh and height taken, and identified to species and morpho-species level. The total and relative values of each family for density, diversity, dominance and Importance Value Indices were calculated. A total of 1062 stems were recorded on the plot (1019 live, 43 dead) with a total of 278 species representing 110 genera in 49 families. The most ecologically significant family as determined by the Family Importance Value (FIV) was Euphorbiaceae with a value of 40 and'the'most significant species, using the Importance Value (IV), was morpho-speciesFordia splendissima with an IV of 29. The total basal area of all living trees was 31.43m². Forest structure was marked by a few tall (>45m) emergents, for example,Koompassia excelsa, Crypteronia griffithii and two species of the Dipterocarpaceae family, however, lower understorey and sub-canopy species dominated the plot with the average height of all individuals over the hectare being 11m.     

Spatial distribution of canopy and subcanopy species along a sloping topography in a cool-temperate conifer-hardwood forest in the snowy region of Japan

The spatial distributions of canopy and subcanopy species (50cm stem length) were investigated within a plot extending from the top of a ridge to the valley bottom in a cool-temperate old-growth mixed forest, dominated by Cryptomeria japonica and Fagus crenata, in the snowy region of Japan. Based on the longitudinal profile of the slope, the study slope was divided into the relatively gentle upper slope position (US), the steep lower slope position (LS), the flat valley bottom (VB) and the boundary zone between the upper and lower slopes (BS). Spatial dispersal and the association patterns of species were analyzed in upperstory (10cm d.b.h) and understory (<10cm d.b.h) layers. Dominant species in the upperstory layer abruptly changed from Cryptomeria to Fagus at the BS site. In contrast, the understory trees of many species, including shade-intolerant and evergreen species, were independent of the location of conspecific upperstory trees or canopy gaps and extended their distributions on and around the BS site. Significant, diverse canopy and subcanopy species occurred at this site in both upperstory and understory layers. On the BS site, which is the lower margin of Cryptomeria-dominated vegetation, there were many medium-sized C.japonica that were killed by uprooting or breaking of the stems as a result of heavy snow pressure. It is suggested that the snow pressure gradient along a slope has a strong influence on community structure and the maintenance of diverse canopy and subcanopy species in this snowy mixed forest.     

A First Quantitative Census of Vascular Epiphytes in Rain forests of Colombian Amazonia

Epiphytism in Colombian Amazonia was described by counting vascular epiphytes in thirty 0.025-ha (5 × 50 m) plots, well-distributed over the main landscape units in the middle Caquetá area of Colombian Amazonia. Each plot was directly adjacent to a 0.1-ha plot at which the species composition of trees and lianas (diameter at breast height (DBH) 2.5 cm) had been recorded 3 years earlier. The purpose of the study was to explore abundance, diversity, and distribution of epiphytes between the principal landscape units. A total of 6129 individual vascular epiphytes were recorded belonging to 27 families, 73 genera, and 213 species (which included 59 morpho-species). Araceae, Orchidaceae, and Bromeliaceae were the most speciose and abundant families. A total of 2763 phorophytes were registered, 1701 (62%) of which with DBH 2.5 cm. About 40–60% of the woody plants with DBH 2.5 cm carried epiphytes, which points at low phorophyte limitation throughout all landscapes. Epiphytism was concentrated on stem bases. Just as trees, epiphyte species assemblages were well associated with the main landscapes. Contrary to trees, however, epiphyte abundance and diversity (species richness, Fishers alpha index) hardly differed between the landscapes. This calls for caution when explanations for distribution and dynamics of tree species are extrapolated to growth forms with a totally different ecology.     

Structure and floristic composition of the lowland rain forest of Los Tuxtlas,Mexico

Physiognomy, structure and floristic composition of one hectare of lowland tropical rain forest was studied in detail at Los Tuxtlas, Mexico. Physiognomically, the Los Tuxtlas forest should be classified as lowland tropical high evergreen rain forest. The forest showed a closed canopy at 30–35 m. Of all woody, non-climbing species with a DBH1.0 cm 89.4% (94.5% of all individuals) were evergreen, 25.4% (59.5% of the individuals) had compound leaves, and over 80% of species (and individuals) had leaves in the notophyll and mesophyll size classes. The forest structure was characterized by a low density (2976 individuals with a DBH1.0 cm, 346 individuals with a DBH10.0 cm, per ha, excluding vines) with an average basal area (38.1 m², DBH1.0 cm, 34.9 m², DBH10.0 cm, per ha, excluding vines). This was attributed to the relative maturity of the forest on the study plot. The study plot contained 234 species (11 208 individuals with a height 0.5 m), of which 55.1% (34.8% of individuals) were trees, 9.4% (6.8%) shrubs, 3.4% (44.3%) palms, 20.1% (5.2%) vines, 6.8% (8.7%) herbs and 5.1% (0.3%) of unknown lifeform. Furthermore, 58 species of epiphytes and hemi-epiphytes were found. Diversity of trees, shrubs and palms with a DBH1.0 cm was calculated as Shannon-Wiener index (4.65), Equitability index (0.65), and Simpson index (0.10). The dominance-diversity curve showed a lognormal form, characteristic for tropical rain forest. The community structure was characterized by a relative dominance of Astrocaryum mexicanum in the understorey, Pseudolmedia oxyphyllaria in the middle storeys, and Nectandra ambigens in the canopy. Species population structures of 31 species showed three characteristic patterns, differentiated by recruitment: continuously high, discontinuously high, and continuously low recruitment. Height/diameter and crown cover/diameter diagrams suggested a very gradual shift from height growth to crown growth during tree development. Forest turnover was calculated as 138 years. Compared to other tropical rain forests the Los Tuxtlas forest had 1. similar leaf physiognomical characteristics, 2. a lower diversity, 3. a lower density, 4. an average basal area, and 5. a slow canopy turnover.     

Feeding Ecology of Black-headed Uacaris (Cacajao melanocephalus melanocephalus) in Pico da Neblina National Park,Brazil

From June 1994 to October 1995, I conducted a study of the feeding ecology of one group of black-headed uacaris (Cacajao melanocephalus melanocephalus) in Pico da Neblina National Park, Brazil, near the Venezuelan border (01°10N to 00°26S, 65°03W to 66°52W). Of a total of 429 feeding records, 89% corresponded to fruits from which black-headed uacaris ate ripe and unripe seeds, mesocarps and arils. Seeds were the single most important food item year-around, corresponding to 81% of the feeding records for fruits. Black-headed uacaris used 120 different plant species in 32 families as food. The 3 most important plant species in their diet, Micrandra spruceana, Eperua leucantha, and Hevea braziliensis (all trees), accounted for 38% of the feeding records for fruits. These species produced fruits that were protected by very hard green husks, were barochorous, did not have fleshy mesocarps, and were slow to mature, thus being available as unripe fruits for long periods. The second and third most important species in the diet of black uacaris, Eperua leucantha and Hevea braziliensis, were dominant in the forest: approximately 30% of trees 10 cm dbh sampled in a 2-ha botanical transect at the study site. I discuss the formation of large social groups of black-headed uacaris in Pico da Neblina National Park in light of the peculiar floristic composition of the study site.     

Floristic composition, structure, and diversity of four forest plots in the Sierra Maigualida, Venezuelan Guayana

A phytosociological study was carried out in four 1-ha forest plots in the Sierra Maigualida region, Venezuelan Guayana. Density, dominance, and frequency values were calculated as well as the species and family importance values (FIVs) in each plot. A total of 65 families, 232 genera and 533 species were represented in the 4ha of forest. The number of stems 10cmdbh varied from 355 to 563, the number of species from 133 to 191, the genera from 76 to 120, the families from 38 to 51, and the basal area from 20.56 to 40.83m² per hectare. Overall the most species rich family was Fabaceae (38 species), the most numerous in total stems was Burseraceae (165 individuals), and the most dominant in terms of basal area was Sapotaceae (1367.13cm²). The most conspicuous families, as represented among the top five FIV, include Burseraceae in all four plots, Moraceae in three of the plots, and Sapotaceae in two plots. Less than 20% of the total inventory of species are represented in two or more plots. The percentages of species which are unique to a single plot range from 56 to 67%. The within-plot diversities recorded in the present study indicate that the Sierra Maiguailida harbors the richest forests thus far documented in Venezuelan Guayana. Meanwhile, the low between-plot similarity indices reinforce the notion that the species richness of this region is unusually high and suggest the need to extend collections and inventory studies.     

Diversity of forest tree species in Yanbaru,the northern part of Okinawa Island

The natural forests of Yanbaru, in the northern part of Okinawa Island, harbor many endemic and endangered birds and mammals, and are dominated by an evergreen oak, Castanopsis sieboldii. The Simpson diversity (D) and equitability index (J) were calculated using survey data on number of stems ( 4.5 cm DBH) of each species found in sample plots.Near-climax old forests (age 50 yr, without pine trees) showed high species diversity of trees, 0.92 ± 0.01 in D and 0.83 ± 0.05 in J for trees of which DBH 4.5 cm, and 0.81 ± 0.04 in D and 0.75 ± 0.05 in J for trees of DBH 10 cm.These high values are comparable to those of tropical rain forests. Although even young forests showed high species diversity, diversity indices tended to increase with forest age.The U.S. Marine Corps leases the eastern half of Yanbaru which contains most of these near-climax forests. Conservation of natural forests in this area is recommended.     

Importance of topography and soil texture in the spatial distribution of two sympatric dipterocarp trees in a Bornean rainforest

Relationships between spatial distributions and site conditions, namely topography and soil texture, were analyzed for two congeneric emergent trees, Dryobalanops aromatica and Dryobalanops lanceolata (Dipterocarpaceae), in a tropical rainforest in Sarawak, East Malaysia. A 52-ha permanent plot was divided into 1300 quadrats measuring 20m×20m; for each Dryobalanops species, the number and total basal area of trees 1cm in d.b.h. were compared among groups of quadrats with different site conditions. Because spatial distributions of both Dryobalanops and site-condition variables were aggregated, Monte-Carlo permutation tests were applied to analyze the relationships. Both single and multifactor statistical tests showed that the density and basal area distributions of the two species were significantly non-random in relation to soil texture and topographic variables. D.aromatica was significantly more abundant at higher elevations, in sandy soils, and on convex and steep slopes. In contrast, D.lanceolata preferred lower elevations and less sandy soils. In the study plot, there were very few sites (3 of 1150 quadrats tested) where the models of Hayashis method predicted the co-occurrence of the two species. These results suggest that between-species differences in habitat preferences are so large that they alone explain the spatially segregated distributions of these two species within the 52-ha study plot.     

Gap-phase regeneration in a semideciduous mesophytic forest, south–eastern Brazil

The study was carried out in ten natural canopy gaps in the SantaGenebra County Reserve (22°4945S, 47°0633W)in the county of Campinas, São Paulo State, Brazil. The size and canopyopenness of the gaps were studied using hemispherical photographs. Thevegetation survey included all shrubs and trees with height 0.50m in the gaps interiors and all the individuals with PBH(perimeterat breast height) 15 cm in a 3 m surroundingborder of the gaps. The similarity among the gaps and among their surroundingareas was assessed by the Jaccard similarity index and by cluster analyzes. Thegap size varied from 20.09 to 468 m², with apredominance of small gaps. The families with the greatest species richness inthe gaps were Rutaceae, Rubiaceae and Euphorbiaceae. The species with thegreatest number of individuals in the gaps were Coffeaarabica L., Hybanthus atropurpureus (St. Hil.)Taub. and Actinostemon klotschii (Muell. Arg.) Pax, allwidely distributed in the understorey. Shade-tolerant species (late secondaryspecies) predominated in function of the predominance of small gaps. The highnumber of species found in the gaps reflects the importance of thesedisturbances in the maintenance of species diversity in the studied forest.     

Optimization of culture conditions for growth of the green alga Haematococcus pluvialis

The effects of light intensity, inoculum volume, sodium nitrate and carbon dioxide concentrations on the growth of Haematococcus pluvialis were investigated using response surface methodology (RSM). All the four variables exhibited significant effects on growth and can be related (r 0.926, P 0.01) by a second-order polynomial consisting of linear, quadratic and interaction terms. The total quadratic effect (P 0.01) dominates over the total linear effect (P 0.01) but the role of interaction terms (P 0.10) is marginal. The optimum values of these variables were: carbon dioxide 1.54%, sodium nitrate 1.06 g/l, inoculum volume 24.97% and light intensity 2.42 klux; the predicted maximum value for the yield of biomass was 0.51 g/l (dry weight).     

Production of a novel syrup containing neofructo-oligosaccharides by the cells of Penicillium citrinum

A novel syrup containing neofructo-oligosaccharides was produced from sucrose (Brix 70) by whole cells of Penicillium citrinum. The efficiency of fructo-oligosaccharides production was more than 55% and those of the main carbohydrate components, 1-kestose (Fruf 21Fruf 21 Glc), nystose (Fruf 21Fruf 21 Fruf 21 Glc) and neokestose (Fruf 26 Glc12 Fruf), were 22, 14 and 11%, respectively.     

Variability in the 11S globulin fraction of seed storage proteins ofHelianthus (Asteraceae)

The seed storage globulins from sixHelianthus and four hybrids were studied using mono and bidimensional gel SDS electrophoresis (+ 2 mercaptoethanol). The polypeptide composition of each subunit was determined. Different pairs are specifically expressed according to the species studied. Three typical patterns were discriminated. All the studied species exhibit five subunits: two of them are expressed in all the species (₁₁ and ₂₂). The subunit corresponding to the ₁₁ pair is present inH. petiolaris and in the three populations ofH. annuus studied. The _2b2 pair is common toH. annuus andH. argophyllus. H. petiolaris presents two specific _2a2 and ₄₄ pairs andH. annuus a specific ₃₃ pair. InH. argophyllus _{11 33} or ₄₄ are never observed but are replaced by ₁₃ and ₃₁ pairs. Some globulins, poorly represented, are of forms but present chains of higher molecular weights (in the range 54–56 kDa). Expressing variations in the banding patterns between these species by the use of a similarity index reveals complete identity between the three populations ofH. annuus. Identity between the twoH. petiolaris studied is also observed.H. annuus andH. argophyllus appear to be closer to each other thanH. petiolaris concerning the seed storage globulins.     

Effects of aquatic macrophytes on water quality and phytoplankton communities in shallow lakes

We investigated aquatic macrophytes, water quality, and phytoplankton biomass and species composition in three shallow lakes with different levels of vegetation cover and nutrient concentration in Kushiro Moor, during August 2000. Trapa japonica can live in a wide range of nutrient levels. This species forms an environment with a steeper extinction of light, higher concentrations of dissolved organic carbon (DOC), lower concentrations of dissolved oxygen (DO) near the bottom, and lower concentrations of nitrate+nitrite and soluble reactive phosphorus (SRP) than other vegetation types. The pH was much higher in a Polygonum amphibium community, and the DO near the bottom did not decrease compared to a T.japonica community in the summer. The relationship between chlorophyll a and the limiting nutrient (total phosphorus (TP) when total nitrogen (TN):TPis 10 and TN/10 when TN:TP is <10) significantly differed between lakes with and without submerged vegetation. The chlorophyll a concentrations at a given nutrient level were significantly lower in water with submerged macrophytes than in water without them. Correspondence analysis showed that the difference in phytoplankton community structure across sites was largely due to the presence or absence of submerged macrophytes, and the ordination of phytoplankton species in the lakes with submerged macrophytes is best explained by environmental gradients of TN, chlorophyll, pH and SRP.     

Tree competition and species coexistence in a warm-temperate old-growth evergreen broad-leaved forest in Japan

The growth dynamics and mode of competition between adult trees 5.0cm in diameter at breast height (DBH) of nine abundant treespeciesoccupying ca. 85% of the total basal area were investigated in a 4ha study plot (200 m × 200 m) of awarm-temperate old-growth evergreen broad-leaved forest in the Tatera ForestReserve of Tsushima Island, southwestern Japan. In the plot, adult trees 5.0 cm DBH co-occurred with 35 woody plant species (except forwoody vine species). The most dominant and largest species,Castanopsis cuspidata var. sieboldiiexhibited a bimodal DBH distribution; it was found in both the upper and lowervertical layers. Other tree species had unimodal DBH distributionscorrespondingmostly to the lower vertical layer. We developed a model for individual growthincorporating both intra- and interspecific competition and degree ofcompetitive asymmetry. One-sided interspecific competition was detected in 17cases out of the 66 possible combinations on the scale of the 4 hastudy plot. The direction of interspecific competition was generally one-sidedfrom layer-I species to layer-II and III ones. The effects of two-sidedcompetition were detected only in layer-II and III species. OnlyDistylium racemosum exhibited one-sided intraspecificcompetition. We also found 11 cases of positive interspecific relationships.Generally, competitive relationships prevailed over positive relationshipsbetween adult trees in this warm-temperate evergreen broad-leaved forest.Competition between adult trees 5.0 cm in DBH did not occurinthe same vertical layer, but occurred only between trees in different verticallayers. This suggests that competition between adult trees 5.0cm in DBH plays a key role in the variation in species coexistencebetween different vertical layers on the 4 ha scale of thewarm-temperate evergreen broad-leaved forests. Moreover, it was found bycomparing with three different forest types that interspecific competition ismore intense in warm-temperate forests than in cool-temperate or sub-borealforests. We conclude that, compared to cool-temperate or sub-boreal forests(which have little interspecific competition), warm-temperate forests supportmore complex interspecific relationships and species-specific habitatpreferences that result in higher species diversity.     

In vitro reconstitution of rice anthranilate synthase: distinct functional properties of the α subunits OASA1 and OASA2

Anthranilate synthase (AS) is a key enzyme in the biosynthesis of various indole compounds including tryptophan. AS consists of two subunits, and , and converts chorismate to anthranilate. Two or more AS -subunit genes have been identified and characterized in several land plants. Although subunits of AS induced by elicitation have been suggested to play significant roles in secondary metabolism, the biochemical and precise functional properties of individual AS isozymes have remained unclear. We have previously identified and characterized two AS -subunit genes (OASA1 and OASA2) in rice (Oryza sativa). To provide further insight into the enzymatic functions of AS isozymes in rice, we have now isolated rice cDNAs encoding the AS subunits OASB1 and OASB2 and reconstituted AS isozymes in vitro with the wheat germ cell-free system for protein expression. Both OASB subunits conferred glutamine-dependent AS activity on either OASA1 or OASA2, indicating the absence of a marked functional difference between the two subunits in terms of amidotransferase activity. Furthermore, both OASA subunits required assembly with a subunit to achieve maximal enzymatic activity even with NH ₄ ⁺ as the amino donor. The V _max and K _i for tryptophan of the OASA1-OASB1 isozyme with glutamine as the amino donor, however, were 2.4 and 7.5 times, respectively, those of OASA2-OASB1, suggesting that AS isozymes containing OASA1 possess a higher activity and are less sensitive to feedback inhibition than those containing OASA2. Our biochemical characterization of reconstituted AS isozymes has thus revealed distinct functional properties of these isozymes in rice.     

Changes in density, biomass, seed production and soil seed banks of the non-native invasive plant, Chromolaena odorata, along a 15 year chronosequence

The non-native invasive plant Chromolaena odorata (Asteraceae) was studied at 6 sites, with a chronosequence of ages from <1 to 15 years, at St Lucia, South Africa. C. odorata density, biomass, seed production and soil seed banks were quantified in three microsites: sun, semi-shade and shade. C. odorata density decreased with invasion age, apparently as a self-thinning process. Biomass per unit area and seed production/plant increased over the first 10 years, but declined greatly at 15 years. C. odorata plants grew larger and had much greater seed production in the sun relative to semi-shade, with small plants producing few if any seeds in the shade. Seed production in the sun varied from 2000 (<1-year old site) to 260000 (10 year) seeds m^–2 annum^–1. About 20–46% of seeds produced were germinable and showed the same trend with age of invasion, but was particularly low after 15 years. Assessment of soil seed banks immediately prior to seed production (seed 10 months old), indicates that about 5–10% of seeds in the sun and 11–22% in the shade were still germinable, resulting in germinable seed densities of 12–385 and 158–511 m^–2, respectively (excluding the 15-year old site). A greenhouse trial showed that burial of seeds, relative to those at the surface, and provision of less water, significantly improved seed persistence in the soil, while light intensity had no effect. Control of C. odorata is difficult due to rapid attainment of reproductive maturity, large production of wind-dispersed seeds and a short-term persistent seed bank. An integrated control strategy either excluding fire (coastal forest sites) or using fire prior to seed release in July/August to kill plants and soil-stored seeds immediately prior to seed production, together with biological, chemical and/or physical control, should be explored.     

Die Homologie des Perigons der Zingiberaceen Ein Beitrag zur Morphologie und Phylogenie des Monokotylen-Perigons

Nicolaia elatior is used as an example to demonstrate that the mucronate tepals ofZingiberaceae correspond to hypsophylls (bracts) consisting of a leaf sheath and a rudimentary Oberblatt (= leaf petiole + lamina) represented by the mucro. Evidence for this interpretation is furnished by all available criteria: leaf sequence (exhibiting a complete continuum of forms from foliage leaves over cata- and hypsophylls to the tepals), nervature, and ontogeny.The present conception is compared with the well-founded thesis ofLeinfellner that the perigone ofLiliaceae is derived from the androecium. The different morphological status of the perigone in both families is not regarded as the result of different phylogenetic origin, but as a manifestation of morphogenetic transgressions from one phyllome category to an adjacent one: In theLiliaceae the perigone is under a strong morphogenetic influence of the androecium, and therefore displays staminal characters, in theZingiberaceae it is under the dominating influence of the extrafloral region, and thus appears as a hypsophyllous structure. If this assumption of a morphologically oscillating perigone is correct, it will be fundamentally impossible to demonstrate unequivocally the phylogenetic origin of the monocotyledonous perigone.

Im wissenschaftlichen Werk Prof. Dr.Walter Leinfellners steht an erster Stelle die Morphologie der Blütenorgane. Als sein dankbarer Schüler möchte ich ihm aus Anlaß seines 70. Geburtstages die folgende Studie zu einem Thema zueignen, das ihn wie mich gleichermaßen angesprochen hat und schon Gegenstand der Forschungsarbeit des Jubilars war: die Homologie des Monokotylen-Perigons.