Apiaceae Species Research Articles

Occupational rhinoconjunctivitis and food allergy because of aniseed sensitization

Aniseed is a spice frequently used in Mediterranean cooking and, as with other Umbelliferae, it has been involved in clinical allergy. This investigation was undertaken to study the allergens implicated in a case of occupational allergy to aniseed associated with rhinoconjunctivitis and gastrointestinal symptoms. Skin prick tests were performed to inhalant allergens, spices used in the patient's workplace (aniseed and cinnamon), and 12 other Umbelliferae spices, birch, and mugwort. A nasal challenge test to aniseed and cinnamon and a double-blind placebo-controlled oral food challenge test to aniseed were also performed. The molecular weights of the allergens were studied by sodium dodecyl sulfate-polyacrylamide gel electrophoresis immunoblotting and cross-reactivity among Umbelliferae species by enzyme immunoassay inhibition. Skin prick tests showed a positive immediate response to aniseed, asparagus, caraway, coriander, cumin, dill, and fennel extracts, and an intense late response to aniseed. Skin prick tests to celery, carrot, birch pollen, and mugwort pollen extracts were negative. Results of a nasal challenge test were positive to aniseed and negative to cinnamon; an aniseed oral food challenge test yielded a positive response. The molecular weights of the main immunoglobulin (Ig)E-binding proteins in aniseed extracts were approximately 48, 42, 39, 37, 34, 33, and 20 kD. Caraway, fennel, cumin, and coriander extracts showed similar IgE-binding patterns. Enzyme immunoassay inhibition studies with the patient's serum revealed cross-reactivity among the IgE components from aniseed, caraway, coriander, fennel, and dill extracts. We demonstrate the presence of aniseed allergens in a case of occupational rhinoconjunctivitis and food allergy, with molecular weights for this spice that differed from those previously reported.

Relationships among genera in Saniculoideae and selected Apioideae (Umbelliferae) inferred from nrITS sequences

AbstractThe internal transcribed spacers (ITS1 and ITS2) of 18S­26S nuclear ribosomal DNA were newly sequenced for eight species of Umbelliferae (six species from subfamily Saniculoideae: Actinolema macrolema, Astrantia minor, Eryngium giganteum, E. coeruleum, Hacquetia epipactis, and Lagoecia cuminoides, two species from subfamily Hydrocotyloideae: Dickinsia hydrocotyloides and Azorella trifurcata), as well as Hohenackeria exscapa, a species of uncertain position in the family. Phylogenetic analyses of new data, plus previously reported sequences of 52 other species using neighbor­joining, maximum parsimony, and maximum likelihood methods yielded similar results: (1) Actinolema is sister to Astrantia corresponding to Drude's treatments; (2) in Astrantia, molecular divergence is revealed between sects. Astrantiella (A. minor) and Astrantia (A. major, A. maxima); (3) Eryngium appears to be paraphyletic; (4) Hacquetia might be treated as a part of Sanicula; and (5) Lagoecia is very distant from all other Saniculoideae and close to some genera of Apioideae. Our results correspond to matK data previously published: (1) Hohenackeria forms a clade with Bupleurum, in a position near the base of the Apioideae tree; (2) Azorella is sister to a large cluster uniting all Saniculoideae and Apioideae, being slightly closer to them than to the Hydrocotyle­Araliaceae clade; (3) Dickinsia is very distant from phenetically similar Hydrocotyle, falling within a large cluster of Apioideae, but also including Lagoecia and Naufraga.

Seed dispersal and seed bank dynamics of the endangered Changium smyrnioides

Changium smyrnioides is an endangered species of Umbelliferae. Its cytology, pollen morphology, geological distribution, and genetic diversity have been studied, but the ecological characteristics of its seeds still remain unknown. To understand the mechanism of endangerment of C. smyrnioides, seed production and dispersal and the dynamics of its seed bank were investigated by random sampling methods. Seed production of C. smyrnioides is 132 seeds/individual, 86.4% of which are from the top inflorescence. The kilo-grain weight of seeds is different between habitats. The scape (averaged 1.06 m in height) to C. smyrnioides often falls to the ground, so seeds fall far from their mother plant. The seed dispersal pattern is contagious. Compared with Anthriscus sylvestris, another species of Umbelliferae, seed production and seed bank density of C. smyrnioides in different periods is much less. Both seed banks are non-persistent. C. smyrnioides maintain the seed bank by multi-procreation, while A. sylvestris is maintained by clonal reproduction. C. symyrnioides has adopted a K=strategy, with low seed number, large seed size and dispersion far from the mother plant so as to avoid density competition among the seedlings. Therefore, when it is disturbed by humans, by digging for medicinal use and deforestation, the population cannot recover quickly. A sylvestris has adopted a r-strategy, with high seed number, small seed size, dispersion near the mother plant, and production of ramets. Its population can recover quickly when it is disturbed by humans.

Micro-Distilled Volatile Compounds from Ferulago Species Growing in Western Turkey

Twelve Ferulago (Apiaceae) species growing in Turkey, viz. F. asparagifolia Boiss., F. aucheri Boiss., F. confusa Velen., F. galbanifera (Miller) W. Koch., F. humilis Boiss., F. idaea N. Özhatay et E. Akalin, F. macrosciadia Boiss. et Bal., F. mughlae Pesmen, F. sandrasica Pesmen et Quezel., F. silaifolia (Boiss.) Boiss., F. sylvatica (Besser) Reichb., and F. trachycarpa Boiss. were investigated for their chemical compositions by using a new technique: microdistillation. Milligram quantities of dried materials were sufficient for characterizing the composition of the volatiles using a GC/MS system.

Chemistry of New Zealand Apiaceae: a rare phenylpropanoid and three new germacrane derivatives from Anisotome lyallii.

A phytochemical investigation of the New Zealand endemic Apiaceae species Anisotome lyallii Hook.f. yielded (+)-alpha-angeloyloxylatifolone (1), 6-O-angeloyl-8-O-tigloyl-6beta,8alpha,11-trihydroxygermacra-1(10)E,4E-diene (2), 6-O-tigloyl-8-O-tigloyl-6beta,8alpha,11-trihydroxygermacra-1(10)E,4E-diene (3) and 6-O-tigloyl-8-O-tigloyl-1alpha,6beta,8alpha,11-tetrahydroxygermacra-4E,10-(14)diene (4). The structures were elucidated by HR mass spectrometry and 1D- and 2D-NMR spectroscopy. A chemosystematic survey for compounds 1-3 in other New Zealand Apiaceae by HPLC-MS revealed that 1-3 were confined to A. haastii Cockayne & Laing and A. lyallii, and that some minor compounds in other species of Anisotome were isomers of 2 and 3.

Purification and Antigenicity of Flavone Synthase I from Irradiated Parsley Cells

Flavone synthase I, a soluble 2-oxoglutarate-dependent dioxygenase catalyzing the oxidation of flavanones to flavones in several Apiaceae species, was induced in parsley cell cultures by continuous irradiation with ultraviolet/blue light for 20 h. The enzyme was extracted from these cells and purified by a revised purification protocol including the fractionation on hydroxyapatite, Fractogel EMD DEAE, and Mono Q anion exchangers, which resulted in an apparently homogeneous flavone synthase at approximately 10-fold higher yield as compared to the previous report. The homogeneous enzyme was employed to raise an antiserum in rabbit for partial immunological characterization. The specificity of the polyclonal antibodies was demonstrated by immunotitration and Western blotting of the crude ammonium sulfate-fractionated enzyme as well as of the enzyme at various stages of the purification. High titer cross-reactivity was observed toward flavone synthase I, showing two bands in the crude extract corresponding to molecular weights of 44 and 41 kDa, respectively, while only the 41 kDa was detected on further purification. The polyclonal antiserum did not cross-react with recombinantly expressed flavanone 3β-hydroxylase from Petunia hybrida or flavonol synthase from Citrus unshiu, two related 2-oxoglutarate-dependent dioxygenases involved in the flavonoid pathway.

Pollen analysis of honeys from the Gharb region (NW Morocco)

The pollen spectra in 18 honey samples from the Gharb region (Northwest of Morocco) have been studied. The samples were collected directly from the beekeepers, both professional and amateurs. The results show that nectar was the main honey source in this region, although one forest or mixed honey was detected. Seven samples belonging to the Class I, five to the Class II and six to the Class III were found. In all the samples some honeydew indicator elements were detected, with HDEN/NPGN= 0.005-1.38. By the qualitative results 58 pollen types belonging to 28 families were identified. Some species of Lythrum , Eucalyptus , Trifolium , Citrus , Mentha , Apiaceae and Scrophulariaceae are the main nectar sources,and some of Asteraceae, Quercus sp., Olea europaea , Plantago sp. and Fragaria 2 ananassa are the most important pollen sources. At least 14 unifloral honeys (c. 77%) from Citrus , Eucalyptus , Lythrum , Mentha and Teucrium were detected.

Field experiments on seed dispersal by wind in ten umbelliferous species (Apiaceae)

This report presents data from experiments on seed dispersal by wind for ten species of the family Apiaceae. Seed shadows were obtained in the field under natural conditions, using wind speeds between four and ten m/s. The flight of individual seeds was followed by eye, and seed shadows were acquired, with median distances varying from 0.7 to 3.1 m between species. Multiple regression models of wind speed and seed weight on dispersal distance were significant for six out of ten species; wind speed had significant effects in seven cases, but seed weight only once. A good correlation between mean terminal falling velocity of the seeds of a species and median dispersal distance, indicates the promising explanatory power that individual terminal velocity data might have on dispersal distance, together with wind speed and turbulence. The theory that seeds that seem to be adapted to wind dispersal travel much longer distances than seeds that have no adaptation was tested. Flattened and winged seeds were indeed found to be transported further by wind, but not much further. Moreover, the species with wind-adapted seeds were also taller, being an alternative explanation since their seeds experienced higher wind speeds at these greater heights. Furthermore, flattened and winged seeds were disseminated from ripe umbels at lower wind speeds in the laboratory. This means that the observed difference in dispersal distance would have been smaller when species specific thresholds for wind speed were incorporated in the field experiments. We argue therefore, that seed morphology is not always the best predictor in classifying species in groups with distinctly different dispersal ability.

An unusual seed-specific 3-ketoacyl-ACP synthase associated with the biosynthesis of petroselinic acid in coriander.

Petroselinic acid (18:1 delta6) is the major component of the seed oil of Umbelliferae species such as coriander (Coriandrum sativum) as well as Araliaceae and Garryaceae species. This unusual fatty acid is synthesized in plastids by the delta4 desaturation of palmitoyl-acyl carrier protein (16:0-ACP) and subsequent elongation of delta4-hexadecenoyl (16:1 delta4)-ACP. To characterize the enzymatic nature of the elongation reaction, an in vitro assay was developed with 16:1 delta4-ACP and 16:0-ACP as substrates. Extracts from developing coriander seeds elongated 16:1 delta4-ACP in a competitive assay at rates ten-fold greater than that with 16:0-ACP. In contrast, extracts from castor seeds, which do not synthesize petroselinic acid, displayed a strong preference for the elongation of 16:0-ACP rather than 16:1 A4-ACP. In addition, the elongation of 16:1 A4-ACP and 16:0-ACP by coriander seed extracts was strongly inhibited by cerulenin at concentrations as low as 10 microM. This finding suggested that the elongation of 16:1 A4-ACP and 16:0-ACP in coriander seed is catalyzed by a 3-ketoacyl-ACP synthase (KAS) 1-type enzyme(s), rather than a KAS II-type activity that is typically associated with 16:0-ACP elongation. Consistent with this, a cDNA for a diverged form of KAS I was isolated from a cDNA library prepared from developing coriander seed. Using a variety of heterologous probing techniques, no KAS II-type cDNAs could be identified in this library. Multiple alignment of KAS amino acid sequences indicated that, although the polypeptide corresponding to the coriander cDNA is more closely related to KAS I. its active site motif deviates from those found in both KAS I and KAS II enzymes. Also suggestive of a possible role in petroselinic acid synthesis, antibodies raised to the recombinant protein recognize an abundant 45 kDa polypeptide in coriander endosperm that is not detected in coriander leaves. These antibodies also recognize a major band of similar size in developing seeds of English ivy (Hedera helix), an Araliaceae species that also accumulates petroselinic acid in a seed-specific manner.

Expansion and Contraction of the Chloroplast Inverted Repeat in Apiaceae Subfamily Apioideae

Abstract Chloroplast DNA (cpDNA) restriction site maps for 113 species of Apiaceae (Umbelliferae) and the allied families Araliaceae and Pittosporaceae were constructed for two enzymes and examined for variation in position of JLB, the junction between the large single copy and inverted repeat regions that is typically contained within the ribosomal protein S10 operon. With the exception of one large clade in Apiaceae subfamily Apioideae, all species possess a JLB indistinguishable from that found in the vast majority of angiosperms. Within this large clade, however, at least one expansion and seven different contractions of the IR relative to the tobacco JLB were detected, each ranging in size from ∼1–16 kb. Five of the junction shifts are parsimony informative, and three support major clades delimited in earlier phylogenetic studies. In light of cladograms based on previous studies of restriction site and DNA sequencing data, the IR appears to have expanded and contracted a minimum of ten times during t...

Closest relatives of Chinese genus Arcuatopterus (Umbelliferae) in the Indian Subcontinent

AbstractIt has been shown that the three Umbelliferae species, distributed in Eastern Himalaya, and previously referred to the genera Angelica and Peucedanum, are very similar in their characters, including carpological ones, to the genus Arcuatopterus, which was regarded as Chinese endemic. Three new nomenclatural combinations are proposed. A key is provided to the six species of Arcuatopterus now recognized, and a nomenclatural summary is also given. The generic area does not go limits beyond of the East Asian floristic subingdom (from Sichuan to Nepal, Sikkim and Khasia Hills).

Four new genera of woody Apiaceae of Madagascar

SummaryVan Wyk, B.‐E., Tilney, P. M. & Winter, P. J. D.: Four new genera of woody Apiaceae of Madagascar. – Taxon 48: 737‐745. 1999. – ISSN 0040‐0262.Eight Malagasi species of Apiaceae were previously misplaced in the African genus Heteromorpha but have been recently excluded from it. They, with the E. African species of Pseudocarum, have remarkably unspecialised fruits and do not fit within Drude's classification system for the family, as they combine vittae characteristic of the Saniculoideae and Apioideae. They have oil ducts in the fruit ribs (intrajugal vittae) in addition to the normal ones between the ribs (vallecular vittae). The species (except one) have dentate‐serrate leaf segments, and some also have dentate involucral bracts, reminiscent of the Saniculoideae. These characteristics are interpreted as symplesiomorphies, and the group of species as a whole is undoubtedly paraphyletic. A new generic classification is proposed, and a key to the genera and species is provided. Four genera, Andriana, Cannaboides, Pseudocannaboides, and Tana, are described as new, to accommodate seven species and one additional variety: A. coursii, A. marojejyensis, A. tsaratananensis, C. andohahelensis, C. andohahelensis var. denudata, C. betsileensis, Pseudocannaboides andringitrensis, and T. bojeriana. Pseudocarum laxiflorum and P. laxiflorum var. alticola are additional new combinations.

Comparison between nitrate and ammonium nutrition in fennel, celery, and Swiss chard

To evaluate the chance to reduce leaf NO3 content and to increase capability to use NH4‐N even in the absence of NO3‐N in the nutrient solution, plants of two Apiaceae species, fennel (Foeniculum vulgare Miller var. azoricum Mill. Thell.) and celery (Apium graveolens L. var. dulce Mill. Pers.), and of one species of Chenopodiaceae, Swiss chard (Beta vulgaris L. var. vulgaris), were hydroponically grown in a growth chamber with three different NH4‐N: NO3‐N (NH4: NO3) ratios (100: 0,50: 50, and 0: 100), but with the same total N level (4 mM) for 14 days. Swiss chard growth was inhibited by NH4 nutrition and reached the highest values with the NH4: NO3 ratio 0: 100. For all the morphological and yield features analyzed, fennel and celery resulted to be quite unresponsive to nitrogen (N) chemical form. Water use efficiency increased in Swiss chard and decreased in fennel and celery with the increase of NO3‐N percentage in the nutrient solution. The dependency of N uptake rate on shoot increment per unit root was more conspicuous for Swiss chard than fennel and celery. All species took more NO3‐N than NH4‐N when N was administered in mixed form. In the best conditions of N nutrition, Swiss chard accumulated NO3 in leaves in high concentration (3,809 mg kg"1 fresh mass). On average, fennel and celery accumulated 564 mg NO3 kg−1 fresh mass with the ratio NH4: NO3100: 0 and showed that by using NH4 produce having very low NO3 content can be obtained. By increasing NO3‐N percentage in the nutrient solution; NO3 leaf content of fennel and celery increased remarkably (7,802 mg kg−1 fresh mass with the ratio N H4: NO3 0: 100).

A Molecular Phylogeny of Apiaceae Tribe Caucalideae and Related Taxa: Inferences Based on ITS Sequence Data

Since the tribe Caucalideae was recognized by Bentham and later Boissier for those species of Apiaceae (Umbelliferae) with spines, hooks, tubercles or bristly hairs on the primary and/or secondary ridges of their fruits, there has been considerable disagreement as to its proper circumscription, the relation- ships among its members, and the delimitation of certain genera. A recent checklist of the group recognized 68 species in 21 genera; a previous molecular systematic study, however, excluded Aphanopleura and Psam- mogeton from the tribe. Phylogenetic relationships among all but one of the 19 remaining genera (material from the rare, monotypic genus Angoseseli was not available for examination) and representatives from pu- tatively allied tribes Scandiceae, Laserpitieae, Apieae, and Smyrnieae were inferred from nucleotide sequence variation in the internal transcribed spacer regions of 18S-26S nuclear ribosomal DNA. In all, 29 genera representing 58 taxa were examined. Phylogenies estimated using maximum parsimony, maximum likeli- hood, and neighbor-joining methods give trees of essentially similar topology, and reveal three major lineages of equivocal relationship: (1) Agrocharis, Ammodaucus, Artedia, Cuminum, Daucus, Laser, Laserpitium, Orlaya, Polylophium, Pseudorlaya, and Pachyctenium; (2) Astrodaucus, Caucalis, Chaetosciadium, Glochidotheca, Lisaea, Szov- itsia, Torilis, Turgenia, and Yabea; and (3) Anthriscus, Kozlovia, Myrrhis, Osmorhiza, and Scandix. These groups are provisionally named the Daucus, Torilis, and Scandix subclades, respectively, of a previously delimited Daucus clade. The first subclade contains representatives of Drude's tribe Laserpitieae, whereas the third subclade coincides with Heywood's tribe Scandiceae. Based on those species included in the study, the genera Daucus, Laserpitium, and Torilis are each not monophyletic. Members of tribe Caucalideae Spreng. (Apiaceae; Umbelliferae) are distributed throughout Europe, the Mediterranean region, and southwestern and central Asia, with a few outlying members in North America. Of the 21 genera and 68 species listed in the most recent checklist for the tribe (V. Heywood and S. Jury in Heywood 1982c; Table 1), Daucus is the largest genus with 21 species, followed by To- rilis with 10 species. Daucus is also by far the most economically important member of the tribe, if not the entire family. Three species of Caucalideae are native to the New World: Daucus montanus Humb. & Bonpl., D. pusillus Michx., and Yabea microcarpa (Hook. & Arn.) Koso-Pol. Classification of Apiaceae has been based largely on anatomical and morphological features of the mature fruit (Heywood and Dakshini 1971; Hey-

Proximate composition and biological activity of food plants gathered by chilean Amerindians

The proximate composition and biological activity of food plants and mushrooms gathered by Chilean Amerindians were assessed. The gathered plants served primarily as sources of carbohydrates with highest values for Dioscorea tubers, Prosopis alba pods meal and Bromus catharticus seeds. The mushrooms Clavaria coralloides and Boletus loyus proved to be the best protein sources in our survey, but deficient in the amino acids methionine and cysteine. Some extracts of the plants and mushrooms under study showed biological activity as free radical scavengers, enzyme inhibitors, hypotensive or DNA binding effect. Free radical scavenging activity was detected in Cryptocarya alba fruit extract, while Typha angustifolia showed a strong DNA binding effect at 0.50 mg/ml. Methanolic extracts of the Apiaceae species Sanicula graveolens and Apium australe were moderately active as β-glucuronidase inhibitors at 50 fig/ml.

Two new species of Umbelliferae from Southern Turkey

Two new Umbelliferae species from S Anatolia are described and illustrated: Chaerophyllum aksekiense A. Duran & Duman and Tordylium ketenoglui Duman & A. Duran.

First Report of Celery Mosaic Potyvirus on Dill (Anethum graveolens).

In the spring and summer of 1997, nearly 90% of dill plants (Anethum graveolens L.) cultivated in a crop of Emilia-Romagna region (northern Italy), exhibited viruslike symptoms. Approximately 30% of the plants showed narrowing of the leaf lamina and stunting that evolved to yellow or bronze color. The plants appeared bushy and had low seed production. Electron microscopy of leaf-dip preparations revealed the association of flexuous, potyvirus-like particles of 750 nm in length with diseased dill plants. The identity of this virus was established by differential host reactions and serological assays. It was mechanically transmitted only to Chenopodium amaranticolor Coste et Reyn. and C. quinoa Willd. plants (which showed local chloro-necrotic lesions after about a week), and Petunia × hybrida Hort. Vilm.-Andr. plants (latently infected). No infections were obtained in several inoculated Umbelliferae plants, including dill and celery (Apium graveolens L.). Therefore, our isolate is similar to that described by others (1,2) and unlike the type strain that infects only members of the Umbelliferae. Virus particles reacted in protein A sandwich-enzyme-linked immunosorbent assay with antiserum to celery mosaic potyvirus (CeMV) (supplied from the Istituto di Fitovirologia Applicata, CNR, Turin, Italy). This result was further confirmed by immunosorbent electron microscopy decoration tests. CeMV in the field was likely transmitted to dill by abundant aphid populations from weeds and/or other Umbelliferae species cultivated in the same location. In particular, the weed host Daucus carota L. and the cultivated Petroselinum sativum Hoffm. plants both exhibited bronze foliage and stunting, and were found to be infected by CeMV. This note represents the first report of CeMV in A. graveolens.

Host plant chemistry and preferences in egg-laying Trioza apicalis (Homoptera, Psylloidea)

Sixtee n belonging to the family Apiaceae were examined for their acceptance as host plants by Trioza apicalis in non-choice tests. The number of eggs laid per day varied from 18 on Daucus carota subsp, sativus to zero on Aegopodium podagraria. In a comparative test, the psyllids landed significantly faster and started egg-laying earlier on carrots (D. carota subsp, sativus) than on dill (Anethum graveolens). In a study of shelter plants for T. apicalis, the psyllids survived on spruce, Picea abies, for more than 30weeks, but they died on grass, Phleum pratense and Brachypodium sylvaticum, within 2 weeks. The length of the day is one of the factors regulating hibernation. At 20°C, light regimes shorter than 17 h induced hibernation, while longer light periods led to reproduction. Both the shelter plants and the summer hosts, including the Apiaceae species, released large amounts of monoterpene hydrocarbons, with great differences among the species. The most preferred host plants (carrots) were found to contain (+)- and (-)-c~-pinene and (+)-sabinene, while large amounts ( > 20%) of either (+) - or ( - ) -limonene were released by the species of low preference. ( - ).-c~- Pinene, ( - ) -J3-pinene, and (-) -limonene were the main components of the spruce odour. A multivariate data analysis of the chemical results showed clearly the significant similarities of the summer host and shelter plants (Daucus carota, Picea abies, and Juniperus communis). © 1997 Elsevier Science Ltd

Essential Oils of Mediasia macrophylla (Regel et Schmalh.) Pimen. and Foeniculum vulgare Mill. from Uzbekistan

Water distilled essential oils from two Umbelliferae species of Uzbekistan were analyzed by GC/MS. p-Cymene (27.23%), thymol (15.13%) and carvacrol (12.52%) were the main components among the thirty three constituents characterized in the oil of Mediasia macrophylla, representing 95.7% of the total components detected. Five compounds were identified in the oil of Foeniculum vulgare representing 99.8% of the total oil with (E)-anethol (87.33%) as the major constituent.

Multiple Independent Losses of the rpoC1 Intron in Angiosperm Chloroplast DNA's

Previous studies have shown that in Marchantia, black pine, and the vast majority of angiosperms examined to date, the chloroplast gene rpoCl is interrupted by an intron (of about 750 base pairs), but that in the grasses and one of three subfamilies of cacti (Cactoideae) this intron has been lost. DNA's of the complete rpoCl intron region and portions of the flanking exon regions from 107 species (representing 54 families) of angiosperms were amplified with the polymerase chain reaction (PCR) in order to uncover other instances of intron loss. In addition to grass and Cactoideae chloroplast DNA's, we report that the rpoCl intron is missing from the chloroplast genomes of Scaevola and Goodenia (the only two representatives of Goodeniaceae examined), four of ten species of Passiflora (Passifloraceae), two of four genera of Aizoaceae (Delosperma and Faucaria but not Monilaria or Tetragonia), and one of the eight taxa of Medicago examined (M. suffruticosa subsp. leiocarpa; Fabaceae). Mirroring other instances of intron loss from the chloroplast genome, sequence analysis reveals that, for these taxa, the rpoCl gene has undergone a precise deletion of the intron. For those taxa with the intron, minimal size variation is apparent within the region and, in all taxa investigated, the intron lies in precisely the same position in the gene. Parsimony analyses of partial exon and intron rpoCl nucleotide sequences reveal that the latter, owing to considerable conservation of secondary structure in that region of the intron sequenced, can supply useful characters for phylogenetic analysis at high taxonomic levels. The chloroplast rpoC region, homologous to the ' subunit of Escherichia coli (Migula) Castellani & Chalmers RNA polymerase, is divided into two genes, rpoCl and rpoC2, and is located in the large single-copy region of the plastid genome in most angiosperms (Cozens and Walker 1986; Hudson et al. 1988). These genes, along with rpoB, are cotranscribed as a single operon and encode three subunits of the chloroplast RNA polymerase (Hudson et al. 1988). The gene rpoCl is of systematic interest because it is known to be interrupted by a single intron in most, but not all, land plants. DNA sequencing has revealed that this intron is present in the liverwort Marchantia polymorpha L. (Ohyama et al. 1986), black pine (Pinus thunbergii Parl.; Wakasugi et al. 1994), tobacco (Nicotiana tabacum L. 'Bright Yellow 4'; Shinozaki et al. 1986), spinach (Spinacia oleracea L.; Hudson et al. 1988), and numerous species of Apiaceae and relatives (Downie et al. 1996, and unpubl. data) but absent in rice (Oryza sativa L. 'Nihonbare'; Hiratsuka et al. 1989; Shimada et al. 1990), maize (Zea mays L.; Igloi et al. 1990), and from all examined representatives of one subfamily of Cactaceae (Cactoideae; Wallace and Cota 1996). The absence of an intron in rpoCl, based on heterologous filter hybridization and polymerase chain reaction (PCR) experiments, has also been noted in several other grasses (Agropyron, Avena, Bambusa, Cynodon, Danthonia, Dendrocalymus, Lolium, Secale, and Triticum; Katayama and Ogihara 1993; S. Downie and J. Palmer, unpubl. data). Thus, it is clear that the intron was present in the common ancestor of angiosperms and subsequently lost independently in the lineages leading to the grasses