Combretaceae Species Research Articles

Sapwood and nikhra heartwood volatiles of two Combretaceae species traditionally used in Sudanese cosmetology and therapy

The smoke from Combretum hartmannianum and Terminalia laxiflora sapwood and fermented heartwood (nikhra) are used in body smoke baths and homemade skincare products in Sudan, which are believed to have various health benefits. In this study, the volatiles of sapwood and nikhra were collected using two extraction techniques: a Mono-TrapTM sampling technique (at low temperature) and a smoke trapping system (at high temperature). After GC-MS analysis, the chromatogram of each sample revealed numerous peaks. The detected peaks were identified using the DIST08 mass spectral library database, resulting in known and unknown compounds. The results showed that 1,2,4,5-tetrachloro-3,6-dimethoxybenzene was the major compound in the Mono-Trap and smoke extracts from nikhra samples of C. hartmannianum and T. laxiflora. In contrast, the dominant compounds in the Mono-Trap extracts of C. hartmannianum and T. laxiflora sapwoods were acetonyldimethylcarbinol and cadina-1(10),4-diene, respectively. The largest peaks in the chromatograms of the sapwood smoke extracts of both species corresponded to unknown compounds. Some of the detected compounds are known for their aromatic and pharmaceutical properties. Identifying these aromatic compounds in nikhra and not in sapwood might prove the traditional Sudanese beliefs, and it could potentially improve the manufacturing of health products.

Bioautography-guided HPTLC-MS as a rapid hyphenated technique for the identification of antimicrobial compounds from selected South African Combretaceae species.

Many species within Combretaceae are traditionally used for the treatment of bacterial infections. The similarity in chemistry and antimicrobial activities within the family pose a challenge in selecting suitable species for herbal drug development. This study aimed at rapidly identifying antimicrobial compounds using bioautography-guided high-performance thin-layer chromatography coupled with mass spectrometry (HPTLC-MS). Hierarchical cluster analysis of ultra-performance liquid chromatography-mass spectrometry data from the methanol extracts of 77 samples, representing four genera within Combretaceae, was carried out. Based on groupings on the dendrogram, 15 samples were selected for bioautography analysis against four pathogens (Staphylococcus aureus, Bacillus cereus, Escherichia coli and Salmonella typhimurium). Active compounds were identified using HPTLC-MS analysis of bands corresponding to the inhibition zones. Bioautography revealed 15 inhibition zones against the four pathogens, with the most prominent present for Combretum imberbe. Analysis of the active bands, using HPTLC-MS indicated that flavonoids, triterpenoids and combretastatin B5 contributed to the antibacterial activity. The compounds corresponding to molecular ions m/z 471 (Combretum imberbe) and 499 (Combretum elaeagnoides) inhibited all four pathogens, and were identified as imberbic acid and jessic acid, respectively. Chemotaxonomic analysis indicated that arjunic acid, ursolic acid and an unidentified triterpenoid (m/z 471) were ubiquitous in the Combretaceae species and could be responsible for their antibacterial activities. Application of HPTLC-MS enabled the rapid screening of extracts to identify active compounds within taxonomically related species. This approach allows for greater efficiency in the natural product research workflow to identify bioactive compounds in crude extracts.

Investigating antimicrobial compounds in South African Combretaceae species using a biochemometric approach

Ethnopharmacological relevanceMany species within the family Combretaceae are popular medicinal plants that are used traditionally to treat various conditions, of which many are related to bacterial infections. Global concerns regarding the increasing resistance of pathogens towards currently available antibiotics have encouraged researchers to find new drugs with antibacterial activity, particularly from plant sources. Aim of the studyThis study was aimed at exploring the broad-spectrum antibacterial potential of methanol extracts of species representing four genera of Combretaceae (Combretum, Pteleopsis, Quisqualis, Terminalia), indigenous to South Africa, using a biochemometric approach. Materials and methodsThe microdilution assay was used to determine the antibacterial activities, measured as minimum inhibitory concentrations (MICs), of the 51 methanol extracts representing 35 Combretaceae species, against nine species of pathogenic bacteria. Integrative biochemometric analysis was performed, thereby correlating the MIC values with the metabolomic data obtained from ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) analysis. Orthogonal projections to latent structures-discriminant analysis (OPLS-DA) models were constructed for six pathogens displaying variation in their susceptibility towards the extracts. ResultsEvaluation of the overall MIC values obtained indicated that extracts of species from the four genera displayed the highest activity towards Bacillus cereus ATCC 11778 (average MIC 0.52 mg/mL) and Salmonella typhimurium ATCC 14028 (average MIC 0.63 mg/mL). These bacteria were the most sensitive Gram-positive and Gram-negative bacteria, respectively. Extracts from Combretum acutifolium, Combretum imberbe and Combretum elaeagnoides were the most active, with average MIC values of 0.70 mg/mL, 0.52 mg/mL and 0.45 mg/mL, respectively. Five triterpenoid compounds were tentatively identified as biomarkers from the biochemometric analysis. ConclusionCorrelation of the phytochemistry of species from four genera in the Combretaceae family with antibacterial activity revealed that triterpenoids are responsible for the broad-spectrum antibacterial activity observed.

A synopsis of the native Combretaceae in the Malay Peninsula

A synopsis of the native species of Combretaceae in the Malay Peninsula (Peninsular Thailand, Peninsular Malaysia and Singapore) is presented. A total of 29 species in four genera (Combretum, Getonia, Lumnitzera and Terminalia) are recognised. Keys to genera and species are included with synonymy and typification. In total 63 lectotypifications, three second-step lectotypifications and 11 neotypifications are proposed in the paper.

Chloroplast Genome Sequences and Comparative Analyses of Combretaceae Mangroves with Related Species.

In the Combretaceae family, only two species of Lumnitzera and one species of Laguncularia belong to mangroves. Among them, Lumnitzera littorea (Jack) Voigt. is an endangered mangrove plant in China for the limited occurrence and seed abortion. In contrast, Lumnitzera racemosa Willd. is known as the most widespread mangrove plant in China. Laguncularia racemosa C. F. Gaertn., an exotic mangrove in China, has the fast growth and high adaptation ability. To better understand the phylogenetic positions of these mangroves in Combretaceae and in Myrtales and to provide information for studies on evolutionary adaptation for intertidal habitat, the complete chloroplast (cp) genomes of Lu. racemosa and La. racemosa were sequenced. Furthermore, we present here the results from the assembly and annotation of the two cp genomes, which were further subjected to the comparative analysis with Lu. littorea cp genomes we published before and other eleven closely related species within Myrtales. The chloroplast genomes of the three Combretaceae mangrove species: Lu. littorea, Lu. racemosa, and La. racemosa are 159,687 bp, 159,473 bp, and 158,311 bp in size. All three cp genomes host 130 genes including 85 protein-coding genes, 37 tRNAs, and 4 rRNAs. A comparative analysis of those three genomes revealed the high similarity of genes in coding-regions and conserved gene order in the IR and LSC/SSC regions. The differences between Lumnitzera and Laguncularia cp genomes are the locations of rps19 and rpl2 genes in the IR/SC boundary regions. Investigating the effects of selection events on shared protein-coding genes showed a relaxed selection had acted on the ycf2, ycf1, and matK genes of Combretaceae mangroves compared to the nonmangrove species Eucalyptus aromaphloia. The phylogenetic analysis based on the whole chloroplast genome sequence with one outgroup species strongly supported three Combretaceae mangroves together with other two Combretaceae species formed a cluster in Combretaceae. This study is the first report on the comparative analysis of three Combretaceae mangrove chloroplast genomes, which will provide the significant information for understanding photosynthesis and evolution in Combretaceae mangrove plants.

On the systematic implication of foliar epidermal micro-morphological and venational characters: diversities in some selected Nigerian species of Combretaceae

Foliar epidermal micro-morphology and venation patterns of eleven species representing four genera in the family Combretaceae revealed stable foliar anatomical characters that are diagnostic and are important in separating the taxa. Distinguishing characters of taxonomic significance in the cells and tissues structures of the species include epidermal cell shape, stomata type, stomata frequency, stomata index, trichome micro-morphology and frequency, areolation shape, vein micro-morphology as well as distribution of druses within areoles. Numerous epidermal striations on the abaxial surface of lamina are diagnostic for Combretum zenkeri while C. platypterum is distinctly separated from other taxa by the possession of staurocytic stomata in addition to the prominent a nomocytic and/oranisocytic stomata. The simple unicellular non-glandular trichomes in the genus Combretum indicate a generic attribute classificatory for members of the genus. Druses within the areoles classify C. platypterum, Terminalia catappa, T. superba and Quisqualis indica within and across the genera studied. This study which is in line with most previous studies revealed that characters of epidermal micromorphology andvenation patterns are important in the identification and separation of the taxa discussed, and that the placement of the species in each of their respective genus should be maintained.

Re-greening of agrosystems in the Burkina Faso Sahel: greater drought resilience but falling woody plant diversity

SummaryDroughts and land degradation result in biodiversity and ecosystem service losses with serious implications for human wellbeing. The Sahel region has seen increased plant cover since the end of 1970s–1980s droughts, but understanding the nature and implications of this change remains a priority. This study aimed to assess changes in the woody floristic composition of re-greened agrosystems since the droughts in Burkina Faso. In 148 vegetation survey plots distributed across areas with increasing woody plant cover and those to some extent protected from exploitation, a total of 71 species from 51 genera and 23 families were identified. Compared to pre-drought flora, our measurements show a decline in the diversity and density of woody species. Combretaceae species and thorny species of the genera Acacia and Balanites, which are more tolerant of drought, were the most dominant, indicating a post-drought woody vegetation that is more resistant to water stress. The increased presence of food-producing species in agroforestry parks (cultivated fields with woody plants) seems to reflect the growing needs of the human population.

English

Although intense research has gone into the exploration of various Combretaceae species towards the discovery of therapeutic relevant compounds, their endophytes have never been explored as potential repositories of alternative sources of novel and medically beneficial equivalents. In the present study, five bacterial endophytes (Lysinibacillus, Staphylococcus, Enterobacter, Pseudomonas and Bacillus species) were isolated from different parts (hard stem, leaves and soft stem) of Combretum molle and identified to species level using morphological data and sequencing of the 16S rRNA. Four of the five endophytes showed varying degrees of antimicrobial characteristics against Bacillus cereus, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. Key words: Bacterial endophytes, bioactive compounds, Combretum molle, phylogenetic analysis, medicinal plant.

Assessment of carbon stocks of semi-evergreen forests in Cambodia

Understanding carbon stocks relative to tree species is important for managing tropical forests in a way that will result in the carbon emission reductions and biodiversity conservation required under the REDD+ scheme. Here we analyse inventory data from 179 sample plots in semi-evergreen forests of three provinces in Cambodia. Across all study sites, 5,995 trees with a diameter at breast height (DBH) ≥10 cm, comprising 79 species from 38 families, were analysed. Tree species of the Dipterocarpaceae were most common (10 species), followed by the species of Caesalpinaceae, Combretaceae and Ebenaceae. Analysis of relative carbon stocks (RCS) suggested that Lagerstroemia calyculata Kurz (RCS=14.3%), Syzygium sp. (6.8%), Shorea vulgaris (5.0%), Irvingia malayana (4.8%), Anisoptera costata Kort (4.6%), Vatica astrotricha (4.2%), and Dehaasia cuneata Blume (3.8%) together accounted for 43.6% of the total average carbon stocks of 99.8±4.8 MgC ha−1. We found that carbon stock is highly correlated to basal area (R2=0.993) but not to stem density (R2=0.153). Using carbon stock values, we estimated the carbon emission due to deforestation of semi-evergreen forests to be 8.3 TgCO2 year−1 in Cambodia between 2002 and 2010. These emissions and the loss of 79 tree species in our study sites could be avoided if financial incentives were available for protecting semi-evergreen forests in Cambodia.

Interpopulation variation in the sexual and pollination systems of two Combretaceae species in Brazilian mangroves

Angiosperms have a broad variety of sexual systems, involving hermaphroditic and unisexual flowers. This variety may be related to the pollination mechanism of each species. Among mangroves, sexual divergence is already known in Laguncularia racemosa C.F. Gaertn., with hermaphroditic and androdioecious populations, and there are records of dioecy for Conocarpus erectus L. However, populations of these species in the northern coast of Pernambuco, Brazil, bear fruits in all individuals, a fact that eliminates the possibility of androdioecy and dioecy. In the present study, we investigated the sexual system of L. racemosa and C. erectus in northern Pernambuco, and assessed its relationship with the pollination system of these species. The population of L. racemosa and C. erectus were gynodioecious and andromonoecious, respectively, which is a novelty. Moreover C. erectus flowers also presenting protogyny. Both species were generalistic, as several insect groups pollinated them. There was a partition of pollinators between these species and reproductive efficiency was high, possibly resulting from the fact that both species are self-compatible and autogamous. However, reproductive success was higher in the presence of pollinators. The pollinators’ foraging behavior, with visits to several flowers of the same individual, could increase geitonogamy, but gynodioecy and andromonoecy associated with protogyny minimize self-pollination, which favors the maintenance of these systems. Our results will give support to future research concerning the evolutionary pathway of sexual diversity among different populations of L. racemosa and C. erectus.

Phytochemical and antimicrobial investigations of stilbenoids and flavonoids isolated from three species of Combretaceae

The antimicrobial activity and chemistry of the African Combretaceae has been well studied in recent years. The present study aimed to investigate the phytochemistry and antimicrobial activity of lesser known members of this family viz. C. hereroense, C. apiculatum and C. collinum. Pulverized leaves of C. collinum and C. apiculatum, and the fruit of C. hereroense were extracted with organic solvents and subjected to preparative chromatography. Seventeen phenolic constituents including four phenanthrenes from the fruit of C. hereroense and two known bibenzyls (including a combretastatin) from the leaves of C. collinum were isolated. The compounds were then subsequently tested for their antimicrobial activity against Candida albicans, Mycobacterium fortuitum, Staphylococcus aureus, Escherichia coli and Proteus vulgaris. Pinocembrin showed excellent activity against C. albicans (MIC — 6.25μg/ml), superior to that of the positive control, fluconazole and against S. aureus (MIC — 12.5mg/ml). The phenanthrenes (compounds 1, 2, 3 and 5) showed some activity against M. fortuitum and S. aureus with a uniform MIC of 25μg/ml. From this study it was evident that most stilbenoids and flavonoids from the selected Combretaceae have little or no antimicrobial activity.

Available data and risk assessment of the Brazilian threatened species of Combretaceae

The risk assessment is made up of risk analyses of species extinction in a given time, following the International Union for Conservation of Nature and Natural Resources (IUCN) criteria. In Brazil, the data necessary for risk assessments have poor quality, so we proposed the articulation of previous processes to improve data quality. The main objective of this work was to reassess the extinction risk of Brazilian species of Combretaceae previously considered as threatened, updating conservation data available for these taxa. Our results showed that the processes of taxonomic proceedings; data gathering; data analysis; georeferencing and communication improved the assessments consistency, specially due to systematization of the whole process. Of the 11 selected species for reassessment, five were threatened in the categories VU, EN, CR e CR* and six under significant threat of extinction. However the deficiency of herbaria data, the lack of digitalization of the majority of country collections and the limited access to available literature represent the main obstacles for extinction risk assessments of the Brazilian flora.

Generic status of <i>Quisqualis</i> (Combretaceae), with notes on the taxonomy and distribution of <i>Q. parviflora</i>

The taxonomic status of Quisqualis L., a genus closely related to and sometimes considered congeneric with Combretum Loefl., is discussed. The genus Quisqualis is maintained to accommodate selected African, Indian, Asian and Malesian species (including Q. indica L. and Q. parviflora Sond.). Diagnostic characters for Quisqualis include: leaves with abundant subepidermal crystalliferous idioblasts, each containing a large druse of calcium oxalate; leaves, stems and flowers with stalked glands but no scales; persistent petiole bases that develop into curved spines; petals well developed; hypanthium tubular or cylindrical, usually longer than 20 mm; stamens and style not or scarcely exserted; style adnate to hypanthium for more than half its length. Quisqualis shares a number of morphological similarities with Combretum Loefl. subgen. Cacoucia (Aubl.) Exell Stace sect. Poivrea (Comm. ex DC.) G.Don. Some species of Combretaceae from West, West Central and East Africa have the style adnate to the upper hypanthium and display features reminiscent of both Quisqualis and Combretum. These species also have characters of their own and in the past were placed in different sections under Combretum. It is suggested that at least some of these species may be best classified in genera distinct from Combretum and Quisqualis, one of which is Campylogyne Hemsley. Combretum s.str. is defined on the basis of a combination of characters and includes species of which the upper hypanthium is variable in shape, but when tubular or cylindrical, then always shorter than 20 mm. Other diagnostic characters include: stamens exserted well beyond petals; style exserted and free, but when shortly adnate to upper hypanthium (only at the base or for a short distance), then stamens long-exserted. It is suggested that different pollination strategies have developed independently in the Combretum–Quisqualis clade, resulting in convergent morphological trends in floral morphology. These homoplasious similarities in floral morphology are at the root of the difficulties experienced to demarcate genera. An alternative classification is provided for those preferring to include the southern African Quisqualis parviflora under Combretum s. l. For this purpose, a new combination and name, Combretum sylvicola O.Maurin is provided. Quisqualis parviflora is confined to the Eastern Cape and KwaZulu-Natal coastal regions and does not extend beyond this area as has been claimed by some. A comparative table to differentiate among four groups in Quisqualis and Combretum in Africa, as well as a photo of a herbarium specimen and a distribution map of Quisqualis parviflora, are provided.

INFORMANTS BASED ETHNOBOTANY AND UTILITY EVALUATION OF FIVE COMBRETACEAE SPECIES: DIFFERENTIATION BY ETHNICITY AND GEOGRAPHICAL LOCATION

ABSTRACT In Africa, local communities depend on forests and plants for their daily needs including goods and services. This paper describes ethnobotanical knowledge of five Combretaceae species in western Burkina Faso. Information was obtained from semi-structured interviews, direct observation and personal conversation with local experts and specialists in plant uses. Data were collected in four villages among four ethnic groups. A total of 150 specialist male and female respondents were involved and 400 users were interviewed. The data were analyzed with generalized linear models with binomial errors. The results show that there is a higher share of ethnobotanical knowledge within an ethnic/village group than between ethnic/village groups. The ethnobotanical information was classified in six main categories: food, fodder, construction materials, fuelwood, handicraft and pharmacopoeia, with the six categories except food representing important uses for all the study species. No significant difference was found for gender and age regarding the knowledge of plant species uses, which may be due to the daily life importance, and to the ecological abundance of the selected Combretaceae species.

In vivo antifungal effect of Combretum and Terminalia species extracts on cutaneous wound healing in immunosuppressed rats

Acetone leaf extracts of Combretaceae species Combretum imberbe Wawra, Combretum nelsonii Duemmer, Combretum albopunctatum Suesseng, and Terminalia sericea Burch ex DC and a mixture of asiatic acid and arjunolic acid isolated from C. nelsonii were tested for antifungal activity against Candida albicans, Cryptococcus neoformans, Microsporum canis, and Sporothrix schenckii on wounds of immunocompromised Wistar rats. The therapeutic agents were selected based on low MIC values ranging 0.02–2.5 mg/mL and low toxicity (LC50) ranging 75.7–168.6 μg/mL. Seven circular, full-thickness wounds were made on the back skin of 24 Wistar rats, under general anesthetic and using an aseptic technique. Rats were infected with different fungal pathogens in groups of six. The treatments were administered topically using 20% concentrations of each extract in aqueous cream. Amphotericin B was used as positive control. Erythema, exudate, crust formation, swelling, and ulceration were used to determine the wound healing process. Throughout the experiment, body temperature, measured using a subcutaneous probe, and weight of the rats were found to be within normal ranges. Epithelial closure in all rats occurred by 17 days. There was no significant difference in contraction of the lesion areas treated with different extracts. The variability in erythema at each lesion in rats infected with different fungal pathogens differed with treatments; the lesion without treatment took a longer time to heal in all cases. Exudate formation was observed until day 12 in rats infected with C. albicans and day 8 in rats infected with C. neoformans. In lesions infected with M. canis and S. schenckii, exudate formation was observed until day 10. The treated group presented a rigid, dark, and thick crust formation after day 3 until day 15. During histopathological evaluations, scant fungi were noted in all the wounds, indicating that infection had occurred but had generally cleared. The antifungal potential of crude extracts of selected plants and a mixture of asiatic acid and arjunolic acid on the wounds of immunocompromised rats was confirmed. The extracts of these plants may possibly be further developed into drugs for topical treatment of fungally infected wounds.

Combretum razianum (Combrertaceae), A new species from Karnataka, India

Combretum razianum, a new species of Combretaceae is described and illustrated.

Antifungal activities of seven West African Combretaceae used in traditional medicine

Seven species of Combretaceae were investigated for their antifungal activity against the pathogenic fungi Candida albicans, Epidermophyton floccosum, Microsporum gypseum, Trichophyton mentagrophytes and Trichophyton rubrum. Pteleopsis suberosa and Terminalia avicennioides appear to be the most active plants. Phytochemical screening shows that these plants are particularly rich in tannins and saponins, which might be responsible for their antifungal activity.

Two New Species of Combretaceae from Puntarenas, Costa Rica

Two new species of Combretaceae are described from Costa Rica. Combretum graciliflorum is related to C. cacoucia Exell and is only the second species of section Cacoucia (Aublet) Engler & Diels known in America. Buchenavia costaricensis is the second species of the genus from Central America and is evidently not closely related to the other (B. tetraphylla (Aublet) R. A. Howard). Combretum assimile Eichler is also reported as new to Costa Rica, from the same area as the above two new species (Osa Peninsula, Puntarenas). Among specimens collected in Costa Rica in 19881991 and recently sent to me for naming by the Missouri Botanical Garden are three taxa new to Costa Rica, two of them new to science. The two latter are the first new Central American Combretaceae to be discovered for many years, indicating the need for further detailed studies of the area in question (Osa Peninsula, Puntarenas). Combretum graciliflorum Stace, sp. nov. TYPE: Costa Rica. Puntarenas: Canton de Osa/Buenos Aires, W part of main ridge of Fila Retinto, along and near trail from Palmar Norte to Jalisco, 8?59.5'N, 83?28'W, 780-960 m, 9 Dec. 1988, Grayum & Herrera 9131 (holotype, MO). A speciebus consectionibus floribus extra dense pubescentibus minoribus angustioribusque differt. Pedicelli 37 mm; hypanthium inferius (cum ovario) 3-4 mm; hypanthium superius anguste curvato-infundibuliforme 1017 mm longum (sepalis 2.5-3.5 mm longis inclusis), 3.56 mm latum; petala usque ad 3 mm exserta, ca. 7 x 5 mm, late elliptica. Liana. Minute stalked glands frequent on leaves and inflorescences. Leaves opposite, 3.5-11.5 x 2.5-6 cm, ovate-oblong, abruptly and shortly acuminate at apex, cordate to rounded-cordate at base, with 5-6 pairs of strongly curved lateral veins, densely reddish brown appressed-pubescent on veins, otherwise sparsely pubescent. Petiole 3-6 mm, densely reddish brown appressed-pubescent. Inflorescence a simple, terminal raceme 6-14.5 cm (not fully elongated). Young stems, rachis, bracts, and outside of flowers densely reddish brown appressedpubescent. Lowest bracts ca. 14 x 5 mm, narrowly elliptic, decreasing in size acropetally. Flowers (from base of pedicel to tip of petals, excluding stamens and style) 18-28 mm. Pedicel 3-7 mm. Lower hypanthium (including ovary) 3-4 mm. Upper hypanthium (including sepals) 10-17 mm, narrowly curved-infundibuliform, gradually widening from base, 3.5-6 mm across at base of sepals. Sepals 2.5-3.5 x 2-3 mm, triangular, acute at apex. Petals ca. 7 x 5 mm, broadly elliptic, pubescent, subacute at apex, exceeding sepals by up to 3 mm. Stamens exserted (but broken off). Style exserted at least 10 mm when mature. The label describes the plant as a coarse liana swooping low in forest, with yellowish green petals. However, the petals have dried very dark, and they and the stamens may have been red, as in most members of the same section; the collectors might have been referring to the sepals. I have seen only one sheet of this species, but it is clearly a member of section Cacoucia (Aublet) Engler & Diels (Exell, 1953). This section contains one American species (C. cacoucia Exell) and probably four species in West Africa (Fig. 1). Combretum graciliflorum is readily separable from C. cacoucia because of its much narrower flowers, and comes closer to some of the West African species in flower shape, notably C. mooreanum Exell, C. stenopterum Exell, and some plants of C. bracteatum (M. A. Lawson) Engler & Diels (especially plants formerly segregated as C. gentilii De Wildeman). However, it is distinct from all of these in details of flower structure. The flowers of section Cacoucia are the largest and most highly developed in the genus, with a long curved upper hypanthium, attaining 4.5 cm long in some plants of C. bracteatum (e.g., the type specimen of C. bucciniflorum Exell). They are mostly red or orange in color, have long-exserted stamens and style, and are probably bird-pollinated. The flowers of the new C. graciliflorum are the smallest in the section. The fruits of the West African species of the genus are 5-winged, the wings being wide and thin in C. bracteatum (including C. gentilii and C. bucciniflorum) and C. platypterum (Welwitsch) Hutchinson & Dalziel, and very narrow and corky in C. stenopterum and C. mooreanum. In contrast, the NovoN 5: 106-108. 1995. This content downloaded from 157.55.39.35 on Wed, 31 Aug 2016 04:19:27 UTC All use subject to http://about.jstor.org/terms Volume 5, Number 1 Stace 107 1995 Combretaceae from Costa Rica

Vascular Anatomy of the Flower of Certain Species of the Combretaceae

The floral anatomy of seven species of the Combretaceae has been studied. The peduncle contains an amphipholic siphonostele. A single trace to each bract and two to its axillary flower diverge out from it. Of the two bundles in the base of the inferior ovary, one divides radially to form two and the other, three vascular strands. The odd member of the five bundles so formed is always on the posterior side. All five bundles continue upward inside the wall of the inferior ovary. In its top, after separating off an inner carpellary ring, the five bundles enter the floral tube. The carpellary ring furnishes a single trace to each of the ovules and then becomes weakly differentiated into dorsal and marginal bundles. In certain taxa, all the carpellary bundles vascularise the style and stigma while in others it is the dorsal bundles alone which do so. The five bundles which are present in antisepalous positions in the base of the floral tube ascend upward and give out lateral branches. Two or sometimes more bra...