Phylogeny and circumscription of the near-endemic Brazilian tribe Microlicieae (Melastomataceae)

The members of tribe Microlicieae in the flowering plant family Melastomataceae are nearly all endemic to the cerrado biome of Brazil. Traditional classifications of the Melastomataceae have attributed between 15 and 17 genera to the Microlicieae, but subsequent revisions have circumscribed the tribe more narrowly. The monophyly and intergeneric relationships of the Microlicieae were evaluated through phylogenetic analyses with molecular and morphological data sets. Incorporation of DNA sequences from the intron of the chloroplast gene rpl16 into a previously generated family-wide data set yielded a clade comprising Chaetostoma, Lavoisiera, Microlicia, Rhynchanthera, Stenodon, and Trembleya ("core Microlicieae"), with Rhynchanthera as the first-diverging lineage. The other four genera of Microlicieae sampled are placed in other clades: Eriocnema with Miconieae; Siphanthera with Aciotis, Nepsera, and Acisanthera of Melastomeae; Castratella as sister to Monochaetum of Melastomeae; and Cambessedesia as part of an unresolved polytomy in a large clade that includes most Melastomataceae. Analyses of the chloroplast genes rbcL and ndhF that included three core genera produced similar results, as did the combined analysis of all three data sets. Combined parsimony analyses of DNA sequences from rpl16 and the nuclear ribosomal intercistronic transcribed spacer (ITS) region of 22 species of core Microlicieae yielded generally low internal support values. Lavoisiera, recently redefined on the basis of several morphological characters, was strongly supported as monophyletic. A morphological phylogenetic analysis of the Microlicieae based on 10 parsimony-informative characters recovered a monophyletic core Microlicieae but provided no further resolution among genera. Penalized likelihood analysis with two calibration time windows produced an age estimate of 3.7 million years for the time of initial divergence of strictly Brazilian core Microlicieae. This date is in general agreement with the estimated age of the most active stage of development of cerrado vegetation and implies an adaptive shift from hydric to seasonally dry habitats during the early evolution of this group.     

A revision of Rhynchanthera (Melastomataceae)

The neotropical genus Rhynchanthera (Melastomataceae, Microlicieae) is revised, and 15 of the 84 proposed taxa are recognized; two species are excluded from the genus. The group consists of subshrubs and shrubs with usually purple flowers in thyrsoid inflorescences of uniparous or biparous cymes. It is characterized by androecia with five antepetalous staminodia in addition to the five fertile stamens, and - in most species - dimorphism of the stamens, with one strikingly longer than the other four. The plants always are covered by at least some simple glandular hairs. The majority of the species of Rhynchanthera occur in south-central Brazil, however, the range of the genus extends from southern Mexico to Bolivia and Paraguay. All species grow in wet places in open scrub or savanna vegetation. Micromorphological features of the seeds have been investigated and support the traditional placement of Rhynchanthera in the Microlicieae where it is closest to Microlicia, Lavoisiera , and Trembleya. Two taxa are illustrated with drawings, and the distribution of all is mapped.     

Flavonoids as taxonomic markers in old world Lupinus species

In a leaf survey of 54 specimens of 11 Old World Lupinus species three classes of flavonoids were detected: flavones (in 82%), flavonols (in 36%) and flavone C-glycosides (in 55%). The rough-seeded species were clearly distinguished from the smooth-seeded taxa by the presence of a novel 2′-hydroxyflavone, luteolin and flavone C-glycosides as major leaf constituents and by the absence of flavonols. Within the smooth-seeded species, there are three flavonoid patterns: (a) flavonols only, L. albus; (b) flavones and flavonols, L. luteus, L. hispanicus and L. angustifolius; and (c) flavones only, L. micranthus. L. angustifolius further differed in uniquely producing diosmetin as a major leaf constituent. These divisions coincide exactly with previous groupings based on alkaloidal and morphological data. Amongst the 12 samples of L. angustifolius three chemical races were distinguished and a number of diosmetin glucoside malate esters detected. The flower flavonoid aglycone patterns of the nine Old World species surveyed differed markedly from the corresponding leaf profiles by the presence of flavones: luteolin and apigenin in eight and chrysoeriol in seven species as major constituents, while flavone C-glycosides were found only in trace amount in three species. In a leaf flavonoid survey of 13 representative New World Lupinus taxa, glycoflavones were major leaf components, a variety of methylated flavones were identified and flavonols were absent. The presence of the novel 2′-hydroxyflavone in five New World species may indicate some evolutionary link with the rough seeded taxa of the Old World.     

Biosystematics of the monocotyledoneae—flavonoid patterns in leaves of the liliaceae

In a leaf survey of 168 species of the Liliaceae, most of the major flavonoid classes were found to be represented in the family. Flavonols occurred most frequently: quercetin and kaempferol were detected in 40% and 42% of the sample respectively, while the flavones luteolin and apigenin were present in only 24% and 20% of the sample. Methylated derivatives, i.e. isorhamnetin, diosmetin and tricin were rare. Procyanidins were present in 17 species, flavonoid sulphates in only one species and flavone C-glycosides in only three species. Anthraquinone pigments were identified in species of Aloe Asphodeline and Asphodelus. Three new flavonoid glycosides were characterised during the course of the survey: diosmetin 7-diglucoside in Colchicum byzanthinum and tricin 7-fructosylglucoside and tricin 7-rutinoside-4′-glucoside in Hyacinthus orientalis cv. ‘Quean of the Pinks’. On the basis of the flavonoid survey, the subfamilies of the Liliaceae may be grouped into those containing flavonols only, those with flavones only or those having both flavonols and flavones. Members of the related families: Amaryllidaceae (17 species), Agavaceae (1 species) and Xanthorrhoeaceae (1 species) contained only flavonols. The subfamilies Scilloideae, Asphodeloideae and Melanthioideae show the most chemical variation whilst the Wurmbaeoideae and Lilioideae are the most homogeneous groups. The tribe Scilleae is unusual in that both flavone- and flavonol-containing genera occur and a wide variety of flavonoid types are represented. A comparison of the leaf flavonoids of the Liliaceae with those found in families related to the grasses showed that all except two classes of flavonoid compound (5-methylated flavones and 5-deoxyflavonoids) found in the Juncaceae. Cyperaceae, Palmae and Gramineae are present in the Liliaceae thus supporting the view that all four families could have arisen from Liliaceae-like ancestors.     

Chemodiversity of exudate flavonoids in seven tribes of Cichorioideae and Asteroideae (Asteraceae)

Members of several genera of Asteraceae, belonging to the tribes Mutisieae, Cardueae, Lactuceae (all subfamily Cichorioideae), and of Astereae, Senecioneae, Helenieae and Heliantheae (all subfamily Asteroideae) have been analyzed for chemodiversity of their exudate flavonoid profiles. The majority of structures found were flavones and flavonols, sometimes with 6- and/or 8-substitution, and with a varying degree of oxidation and methylation. Flavanones were observed in exudates of some genera, and, in some cases, also flavonol- and flavone glycosides were detected. This was mostly the case when exudates were poor both in yield and chemical complexity. Structurally diverse profiles are found particularly within Astereae and Heliantheae. The tribes in the subfamily Cichorioideae exhibited less complex flavonoid profiles. Current results are compared to literature data, and botanical information is included on the studied taxa.     

Physical interactions among flavonoid enzymes in snapdragon and torenia reveal the diversity in the flavonoid metabolon organization of different plant species

Flavonoid metabolons (weakly‐bound multi‐enzyme complexes of flavonoid enzymes) are believed to occur in diverse plant species. However, how flavonoid enzymes are organized to form a metabolon is unknown for most plant species. We analyzed the physical interaction partnerships of the flavonoid enzymes from two lamiales plants (snapdragon and torenia) that produce flavones and anthocyanins. In snapdragon, protein–protein interaction assays using yeast and plant systems revealed the following binary interactions: flavone synthase II (FNSII)/chalcone synthase (CHS); FNSII/chalcone isomerase (CHI); FNSII/dihydroflavonol 4‐reductase (DFR); CHS/CHI; CHI/DFR; and flavonoid 3′‐hydroxylase/CHI. These results along with the subcellular localizations and membrane associations of snapdragon flavonoid enzymes suggested that FNSII serves as a component of the flavonoid metabolon tethered to the endoplasmic reticulum (ER). The observed interaction partnerships and temporal gene expression patterns of flavonoid enzymes in red snapdragon petal cells suggested the flower stage‐dependent formation of the flavonoid metabolon, which accounted for the sequential flavone and anthocyanin accumulation patterns therein. We also identified interactions between FNSII and other flavonoid enzymes in torenia, in which the co‐suppression of FNSII expression was previously reported to diminish petal anthocyanin contents. The observed physical interactions among flavonoid enzymes of these plant species provided further evidence supporting the long‐suspected organization of flavonoid metabolons as enzyme complexes tethered to the ER via cytochrome P450, and illustrated how flavonoid metabolons mediate flower coloration. Moreover, the observed interaction partnerships were distinct from those previously identified in other plant species (Arabidopsis thaliana and soybean), suggesting that the organization of flavonoid metabolons may differ among plant species.     

Epicuticular flavonoids of some Scrophulariaceae

Twenty-two species of Scophulariaceae have been found to accumulate flavonoid aglycones externally on their leaves and stems. They belong to the genera Anarrhinum, Antirrhinum, Asarina, Calceolaria, Mimulus, and Odontites. Most of the flavonoids are methylated flavones and flavonols, some with 6-O and/or 8-O-substitution. One of them is the natural isobutyryl ester of a rare flavone.     

Three 2-oxoglutarate-dependent dioxygenase activities of Equisetum arvense L. forming flavone and flavonol from (2S)-naringenin

Equisetum arvense L. (Equisetaceae-horsetail) accumulates various flavones and flavonols in infertile shoot. Enzyme assays conducted with crude extracts of the green tissue revealed chalcone synthase activity and also three further activities assigned to flavonoid biosynthesis and identified as flavone synthase I, flavanone 3β-hydroxylase and flavonol synthase. The latter three activities were characterized as soluble, 2-oxoglutarate-dependent dioxygenases by their typical cofactor requirements and peculiar inhibition. Notably, this is the first report of flavone synthase I which had been considered to be restricted solely to species of the Apiaceae from a distant plant taxon.     

Flavonoid distribution of Mulinum (Apiaceae, Hydrocotyloideae, Mulineae)

Flavonoid chemistry of the genusMulinum and selected Mulineae taxa was studied. Both flavones and flavonols were identified as C- and O-glycosides. AllMulinum species contain 6,8-di-C-glycosyl chrysoeriol (flavone) and, with the exception of one, quercetin (flavonol). The presence of both flavones and flavonols in this genus weakens previous generalizations that the mulineae contain only flavonols and are primitive compared to other Apiaceae tribes. Based on the selected taxa studied,Azorella appears to differ from bothMulinum andGymnophyton in producing more kinds of flavonols, andGymnophyton appears similar toMulinum in the production of both chrysoeriol and quercetin as well as relatively few compounds. The flavonoid profile ofAsteriscium glaucum is reported as well. In general, a more homogeneous flavonoid compound composition for the Apiaceae is suggested.     

Flavonoids from tribe Delphineae (Ranunculaceae): Phytochemical review and chemotaxonomic value

This review summarizes the flavonoids isolated from three genera, namely, Aconitum, Delphinium, and Consolida, belonging to tribe Delphineae in the Ranunculaceae family for the first time. A total of 104 distinct flavonoid components, including 85 flavonols, 13 anthocyanins, four flavones, and two neoflavones, have been isolated from 44 members of tribe Delphineae. Flavonols account for the largest proportion and can be regarded as the dominant group of flavonoids in this tribe. Of the 104 isolated flavonoids, 55 are novel, indicating the high chemical diversity among the flavonoid constituents of Delphineae plants. Flavonoids in Delphineae plants exhibit chemotaxonomic significance, characterizing certain Delphineae species well. Flavonol glycosides, as the major flavonoid constituents in the investigated Delphineae species, could also serve as valuable chemotaxonomic markers in addition to diterpenoid alkaloids for the identification of Delphineae species.     

Anthocyanin pigments and leaf flavonoids in the family araceae

Anthocyanins, variously identified in inflorescence, fruit, leaf or petiole of 59 representative species of the Araccae, are of a simple type. The most common pigment is cyanidin 3-rutinoside, while pelargonidin 3-rutinoside and cyanidin 3-glucoside are regularly present. Two rare pigments are: cyanidin 3-gentiobioside in Anchomanes and Rhektophyllum, both in the subfamily Lasioideae; and delphinidin 3-rutinoside in Schismatoglottis concinna. In a leaf survey of 144 species from 58 genera, flavone C-glycosides (in 82%) and proanthocyanidins (in 35–45%) were found as the major flavonoids. In the subfamily Calloideae, subtribe Symplocarpeae, flavonols replace glycoflavones as the major leaf components but otherwise flavonols are uncommon in the family (in 27% of the sample) and more usually co-occur with flavone C-glycosides. Two new flavonol glycosides were characterized from Lysichiton camtschatcense: kaempferol 3-(6-arabinosylgalactoside)and kaempferol 3-xylosylgalactoside. Simple flavones, luteolin and chrysoeriol (in 6%) were found only in the subtribes Arinae and Cryptocoryninae, subfamily Aroideae. Flavonoid sulphates were identified in only four taxa: glycoflavone sulphates in two Culcasia species and Philodendron ornatum and a mixture of flavone and flavonol sulphates in Scindapsus pictus. Caffeic ester sulphates were more common and their presence in Anthurium hookeri was confirmed. These results show that the Araceae are unusual amongst the monocots in their simple and relatively uniform flavonoid profile; no one subfamily is clearly distinguished, although at tribal level some significant taxonomic patterns are observed. The best defined groups are the subfamilies Lasioideae and Monsteroideae, and the tribes Symplocarpeae and Arophyteae, and the subtribe Arinae. The greatest chemical diversity occurs in Anthurium and Philodendron, but this may only reflect the fact that these are the two largest genera in the family. The origin and relationship of the Araccae to other monocot groups are discussed in the light of the flavonoid evidence.     

A chemotaxonomic survey of the tribe psoraleeae in africa

A study of the leaf flavonoids, furanocoumarins and essential oils of 51 species (three genera) of the tribe Psoraleeae (Fabaceae) has provided chemical data to support the recent subdivision of the large worldwide genus Psoralea into a number of segregate genera. The flavonoid patterns in most species were very similar, consisting largely of proanthocyanidins and complex mixtures of flavone O- and C-glucosides. Psoralea repens, the only maritime species to be examined, is unique in containing only rutin. Three isoflavones (daidzein, formononetin and genistein) were of widespread occurrence. The genera Psoralea and Otholobium, which could not be separated on flavonoid data, were clearly demarcated by their essential oils. Furanocoumarin patterns were useful for the characterization of species.     

VARIATION AND LOCALIZATION OF FLAVONOID AGLYCONES IN HELIANTHUS ANNUUS (COMPOSITAE)

Flavonoid aglycone variation within Helianthus annuus, a species widely distributed throughout North America, was analyzed. Flavonoid aglycones of H. annuus consist of two types, flavones and chalcones. The flavone aglycones are sequestered in glandular trichomes that occur on both leaf surfaces, whereas the chalcone aglycones appear to be incorporated in the waxy leaf cuticle. Considerable variation in flavonoid profile was observed with some plants exhibiting as few as one, and others as many as seven of the eight aglycones detected. No definable phytogeographic patterns were observed for this flavonoid variation. Flavonoid aglycone variation also did not differentiate the infraspecific taxa within H. annuus.     

The role of lipophilic and polar flavonoids in the classification of temperate members of the Anthemideae

Lipophilic and vacuolar flavonoids were separately identified in representative temperate species of the genera Anthemis, Chrysanthemum, Cotula, Ismelia, Leucanthemum and Tripleurospermum. The four Anthemis species investigated variously produced four main surface constituents, in leaf and flower: santin, quercetagetin 3,6,3′-trimethyl ether, scutellarein 6,4′-dimethyl ether and 6-hydroxyluteolin 6,3′-dimethyl ether. By contrast, surface extracts of disc and ray florets of the species of Chrysanthemum, Cotula, Ismelia, Leucanthemum and Tripleurospermum surveyed yielded five common flavones in the free state: apigenin, luteolin, acacetin, apigenin 7-methyl ether and chrysoeriol. Polar flavonoids were isolated and identified in leaf, ray floret and disc floret of all the above plants. Anthemis species were distinctive in having flavonol glycosides in the leaves, whereas the leaf flavonoids of the other taxa were generally flavone O-glycosides. The 3-glucoside and 3-rutinoside of patuletin were characterised for the first time from Anthemis tinctoria ssp. subtinctoria. Two new flavonol glycosides, the 5-glucuronides of quercetin and kaempferol, were obtained from the leaf of Leucanthemum vulgare, where they co-occur with the related 5-glucosides and with several flavone glycosides. The ray florets of these Anthemideae generally contain apigenin and/or luteolin 7-glucoside and 7-glucuronide, whereas disc florets have additional flavonol glycosides, notably the 7-glucosides of quercetin and patuletin and the 7-glucuronide of quercetin. A comparison of the flavonoid pattern encountered here with those previously recorded for Tanacetum indicate some chemical affinity between Anthemis and Tanacetum. Flavonoid patterns of the other five genera are more distinct from those of Tanacetum and suggest that those genera form a related group. All 14 species surveyed for their flavonoid profiles have distinctive constituents and the chemical data are in harmony with modern taxonomic treatments of the “Chrysanthemum complex” as a series of separate genera.     

Leaf flavonoid patterns in the winteraceae

In a leaf flavonoid survey of 59 specimens of the Winteraceae and related families, representing nine genera, luteolin 7,3′-dimethyl ether (in 77%) and flavonols (in 81%) were found to be major constituents. Indeed the high incidence of luteolin 7,3′-dimethyl ether chemically isolates the family from all other angiosperm groups, including families and genera that have been taxonomically associated with the Winteraceae in the past. Simple flavones (in 16%), on the other hand, were found only in some Drimys s. str., Tasmannia and Pseudowintera species. Similarly, the distribution of flavone C-glycosides was restricted to specimens of T. piperita and one specimen of D. winteri. The frequent occurrence of procyanidin (in 60%) and dihydroquercetin (in 44%) reflects the primitive and woody nature of the family. The combined flavonoid data clearly support previous cytological, morphological and phylogenetic studies in the division of the Winteraceae into three groups of genera: (1) Bubbia, Belliolum, Exospermum and Zygogynum; (2) Drimys s. str. and Pseudowintera and (3) Tasmannia. Some generic variations were found within the Bubbia, Belliolum, Expospermum and Zygogynum group but apart from minor geographic variations within Belliolum the flavonoid results do not appear to provide suitable evidence for subgeneric taxonomy.     

Aromatase inhibition by flavonoids

Several synthetic flavones were found to inhibit the aromatization of androstenedione to estrone catalyzed by human placental microsomes. Twenty-one compounds were tested and the IC50 of the most active were: flavone, 10 microM; 7-hydroxyflavone, 0.5 microM; 7,4'-dihydroxyflavone, 2.0 microM; flavanone, 8.0 microM; and 4'-hydroxyflavanone, 10 microM. Most of the others had IC50 values ranging from 80 to greater than 200 microM. These findings show that 4'-hydroxylation results in either no change or very little change in IC50 for flavanone, isoflavone and isoflavanone as well as other ring A hydroxylated flavones. Derivatives of flavone with a hydroxyl substituent at position 5, 6 and 7 were also screened. 7-Hydroxyflavone (11) was the most effective competitive inhibitor (IC50 = 0.5 microM) with an apparent Ki value of 0.25 microM. Compound 11 also induced a change in the absorption spectrum of the aromatase cytochrome P-450 which is indicative of substrate displacement. The relative binding affinities of the flavonoid analogs were determined and only ring A adn ring B dihydroxylated analogs were found to bind to the estrogen receptor.     

Leaf flavonoid patterns in the genus Tricyrtis (Tricyrtidaceae sensu stricto, Liliaceae sensu lato)

In a leaf flavonoid aglycone survey of 19 Tricyrtis species, the flavone lulcolin was detected in 16% of the taxa and the flavonols myricetin, qucrcetin, kaempfcrol and isorhamnetin in 32%, 63% and 68% and 58% of the sample, respectively. Kaempfcrol occurred more frequently than qucrcetin in sections Hirtae and Tricyrtis. Section Brachycyrtis was characterized by the presence of lulcolin, while flavoncs were absent from sections Flavae, Hirtae and Tricyrtis. Myricetin was found only in T J'ormosana and T. hirta (section Hirtae) and in T affirm and T. macropoda (section Tricyrtis). This is the first report of myricetin in Tricyrtis and in the Liliales. Also the co-occurrence of flavones and flavonols within the same plant, as in 7. ishiiana var. surugensis and T macrantha , is a rare event in this order. The flavonoid data are congruent with data from morphology, anatomy and molecular analysis in indicating the separation of section Brachycyrtis from the other three sections and in supporting a close relationship between sections Hirtae and Tricyrtis.     

Flavonol triglycosides from Blackstonia peroliata.

Three new flavonol triglycosides quercetin, kaempferol and isorhamnetin 3-rhamnosyl(1----2)galactoside-7-glucosides have been isolated from leaves and stems of Blackstonia perfoliata. This species together with three other genera of the tribe Gentianeae, subtribe Chlorae: Centaurium, Coutoubea and Eustoma, is unusual in producing flavonol glycosides instead of C-glycosyl flavones, the more characteristic flavonoid constituents of the Gentianaceae.     

The leaf flavonoids of the Zingiberales

A survey of flavonoids in the leaves of 81 species of the Zingiberales showed that, while most of the major classes of flavonoid are represented in the order, only two families, the Zingiberaceae and Marantaceae are rich in these constituents. In the Musaceae (in 9 species), Strelitziaceae (in 8 species) and Cannaceae (1 of 2 species) flavonol glycosides were detected in small amount and in the Lowiaceae no flavonoids were fully identified. In the Zingiberaceae kaempferol (in 22%), quercetin (72%) and proanthocyanidins (71%) are distributed throughout the family. The two subfamilies of the Zingiberaceae may be distinguished by the presence of myricetin (in 26%), isorhamnetin (10%) and syringetin (3%) in the Zingiberoideae and of flavone $\text{C-}\text{glycosides}$ (in 86% of taxa) in the Costoideae. A number of genera have distinctive flavonol profiles: e.g. Hedychium species have myricetin and quercetin. Roscoea species isorhamnetin and quercetin and Alpinia species kaempferol and quercetin glycosides. A new glycoside, syringetin 3-rhamnoside was identified in Hedychium stenopetalum. In the Zingiberoideae flavonols were found in glycosidic combination with glucuronic acid, rhamnose and glucose but glucuronides were not detected in the Costoideae or elsewhere in the Zingiberales. The Marantaceae is chemically the most diverse group and may be distinguished from other members of the Zingiberales by the occurrence of both flavone $\text{O-}$ and $\text{C-}\text{glycosides}$ and the absence of kaempferol and isorhamnetin glycosides. The distribution of flavonoid constituents within the Marantaceae does not closely follow the existing tribai or generic limits. Flavonols (in 50% of species). flavones (20%) and flavone $\text{C-}\text{glycosides}$ (40%) are found with similar frequency in the two tribes and in the genera Calathea and Maranta both flavone and flavonol glycosides occur. Apigenin- and luteolin-7-sulphates and luteolin-7,3′-disulphate were identified in Maranta bicolor and M. leuconeura var. kerchoveana and several flavone $\text{C-}\text{glycosides}$ sulphates in Stromanthe sanguinea. Anthocyanins were identified in those species with pigmented leaves or stems and a common pattern based on cyanidin-and delphinidin-3-rutinosides was observed throughout the group. Finally the possible relationship of the Zingiberales to the Commelinales, Liliales, Bromeliales and Fluviales is discussed.     

Flavonoids in leaves and inflorescences of australian cyperaceae

A survey of 170 Australian species of Cyperaceae belonging to 35 genera has confirmed that this family has a highly characteristic flavonoid pattern in leaf and inflorescence. Aurone pigments, the most distinctive family constituents, were found in the leaves of 25% of the sample and in the inflorescences of 40%. Sulphuretin was found for the first time in the family, in Carex appressa. Flavones, such as tricin and luteolin, are very common; in addition, a variety of methyl ethers were detected. Luteolin 5-methyl ether was found in further genera, while luteolin 7-methyl ether, diosmetin and acacetin were detected for the first time in the Cyperaceae. Flavonols and their methyl ethers occurred in over one-third of the species, particularly in the leaves, being especially well represented in the genera Fuirena, Gahnia, Lepidosperma and Mesomelaena. Myricetin was found only twice, in two Baumea species. The 3-desoxyanthocyanidin carexidin was found in the inflorescences of eight species, i.e. in 5% of the sample. Taxonomically, the results are mainly of interest at the generic and specific level, where the patterns sometimes show useful correlations with morphology. At the tribal level, the Sclerieae are the most distinctive, with higher than average frequency of flavone C-glycosides, flavonols, proanthocyanidins and aurones, and lower than average frequency of flavones.