Towards a molecular phylogeny ofApiaceae subfamilyApioideae: Additional information from nuclear ribosomal DNA ITS sequences

Evolutionary relationships among 116 representatives (80 genera) ofApiaceae (Umbelliferae) subfam.Apioideae were investigated by comparative sequencing of the two internal transcribed spacers of the 18S–26S nuclear ribosomal DNA repeat. The resultant phylogenies, inferred using maximum parsimony and neighbor-joining methods, clarified the relationships of several genera whose phylogenetic placements have heretofore been problematic. Comparisons between the phylogenies inferred and the distribution of several phytochemical (coumarins, flavonoids, and phenylpropenes) and morphological (stomates, pollen, and cotyledonary shape) characters were also made, revealing that many of these characters (like those morphological and anatomical characters of the fruit) are highly homoplastic. It is not surprising then that systems of classification ofApioideae based on these characters, particularly with regard to tribal and subtribal designations and relationships, are unsatisfactory. The results of recent serological investigations of the subfamily support several relationships proposed herein using molecular data.     

Karyotaxonomic study of some species ofPeucedanum (Umbelliferae)

A study of morphometric karyotype characters was carried out in 14 species ofPeucedanum s. lat. (Umbelliferae — Apioideae) and in one species of the related genusLomatium. The differences of the species in their karyotype characters are correlated only to a limited degree with their similarities of dissimilarities in morphological (i. a. carpological) characters, and thus with their taxonomic position. The evolution of these two sets of characters seems to have proceeded not synchronously or even in different directions in the group of platycarpousUmbelliferae united in the genusPeucedanum. Therefore, it is unlikely that morphometric chromosome characters revealed by monochrome staining can be used appropriately in the taxonomic revision of the polymorphous genusPeucedanum.     

Variability in giant fennel (Ferula communis,Umbelliferae): Ribosomal RNA nuclear genes

The rDNA of five accessions of the giant fennel (Ferula communis, Umbelliferae) was analyzed. The restriction map of Bam H 1, Eco R 1 and Hind III sites was established for one of them. Variation between the five accessions was observed at several levels. Three have a homogeneous repeat size, whereas the two others are heterogeneous, one presenting an additional site heterogeneity. However, the general pattern of organization is very similar and there is much greater similarity between theFerula accessions than with the pattern observed for carrot, a plant from the same family. Variation was also observed in the copy number of the rDNA repeats, which ranges from 900 to 3 500. The results demonstrate that the five accessions can be clearly differentiated by molecular analysis of their DNA although they belong to the same species or subspecies. They also demonstrate that different isolated populations of a species evolve independently, thus shedding light on the molecular mechanisms of speciation.     

Non-equivalency of genera inAngiospermae: Evidence from DNA hybridization studies

The problem of taxa equivalency in phylogenetically distant groups can hardly be solved by comparing morphological differences alone. An attempt is made to approach the problem by means of DNA comparisons, e.g., DNA hybridization. Data obtained forCompositae, Umbelliferae andIridaceae indicate that both unique and repetitive DNA sequence comparisons lead to the conclusions that genera within these families are not equivalent, e.g., the differences in the DNA among the species ofIris are much more pronounced than among those ofAchillea; some genera ofUmbelliferae occupy an intermediate position.     

Cladistic interrelationships and major clades of theEricales

A cladistic analysis of theEricales based on morphological, anatomical, embryological, and phytochemical data has been undertaken. Resulting from the analysis, 56 equally parsimonious cladograms were obtained. The tribeEnkiantheae was found to be the sister-group of the rest of theEricaceae, in which theEmpetraceae, theEpacridaceae, Pyrolaceae, andMonotropaceae are forming derived ingroups. It is thus concluded that theEricaceae are a paraphyletic assemblage as presently circumscribed, and thatEmpetraceae andEpacridaceae are better treated as members of theEricaceae.     

Karyotaxonomic analysis of the genusBunium (Umbelliferae)

Chromosome numbers are reported for 23 species of the genusBunium, distributed mainly in Middle Asia and Transcaucausia. The great diversity of basic chromosome numbers is unusual for a genus ofUmbelliferae: x = 11, 10, 9, 8, 7, and 6. This series obviously has to be interpreted as descending dysploidy. Infraspecific aneuploidy was found in three species, but there are no B-chromosomes or polyploidy. The karyotypes of 18 species are described, using two morphometric chromosome parameters, centromere position and relative length (Table 2), and illustrated (Figs. 2–4). Species vary greatly in their karyotype asymmetry (20.4–45.9%). Chromosome numbers and structures appear to be useful in the karyotaxonomical and biogeographical analysis of the genus.     

Models and reality: Doctrine and practicality in classification

Phenetic classification corresponds to no biological model and lacks a sound philosophical basis. Cladistics (ignoring meaningless “transformed cladistics”) assumes divergent evolution and, usually, that best estimates of phylogeny are obtained by parsimony principles, both questionable assumptions at times. It is better than phenetics since more-or-less testable hypotheses are generated, but pitfalls are many, in data selection and interpretation (as to homology), and in commensurability of units and direction of change. Above all we learn: homoplasy is rife in nature. Much bad cladistics has been done. If it is to reflect phylogeny, classification cannot be artificially stabilized, but is its only aim to express (hypothesized) cladistic patterns? And can it do that with any degree of overall assurance? Biologists are legitimately interested in defining grades as well as clades. Recognition of an unequivocal clade-grade frequently leaves a paraphyletic grade residue that cannot itself be unequivocally resolved. This is a real problem that requires attention in formal taxonomy and in applying cladistics. Primarily morphological cladistics will be increasingly supplanted by molecular (nucleotide-sequence) cladistics. The role of evolutionary taxonomy will change accordingly.     

Species boundaries,phylogenetic relationships,and ecological differentiation inAnthriscus (Apiaceae)

Species boundaries and phylogenetic relationships of 17 taxa ofAnthriscus (Apiaceae), with special emphasis on the critical sect.Cacosciadium, were explored using morphological data with principal component analysis, phenetics, and phylogenetics. The analyses did not provide satisfactory resolution of taxa from sect.Cacosciadium and only four species were retained. The total number of species was reduced to nine. Sect.Cacosciadium is distinguished by only two synapomorphies while sects.Anthriscus andCaroides are better supported. Present geographic and ecological variation suggests that the radiation ofAnthriscus occurred through divergence of peripheral isolated populations adapting to different habitats: high montane meadows and screes, shady climax forests, and seasonally dry habitats at lower altitudes. The adaptive significance of particular morphological traits is discussed.     

Relationships among Cichorium species and related genera as determined by analysis of mitochondrial RFLPs

Mitochondrial DNA polymorphism was employed to assess cytoplasmic diversity among cytoypes of the genus Cichorium and related genera of the tribe Lactuceae (Asteraceae). Hybridization patterns of total DNA using six restriction enzymes and five heterologous mtDNA probes were examined. From estimates of mtDNA diversity, Cichorium spinosum appeared as an ecotype of C. intybus rather than a separate species. Interspecific mtDNA polymorphism in the genus Cichorium was higher than that observed in Cicerbita Crepis, Lactuca and Tragopogon. Molecular data seemed to indicate that Catananche is very distant from the other genera examined. Intergeneric comparisons allowed the clustering of Cicerbita, Lactuca and Cichorium, genera which belong to different subtribes. However, further molecular investigations on a larger number of genera are needed to clarify the relationships among genera within and between subtribes of the tribe Lactuceae.     

Taxonomy and phylogeny of the tribePlucheeae (Asteraceae)

The tribePlucheeae (Benth.)A. Anderb., has been analysed cladistically by means of a computerized parsimony program (Hennig 86), using theArctotideae as outgroup. The results of the analysis are presented in a consensus tree and one cladogram. Four major monophyletic subgroups can be recognized: TheColeocoma group (3 genera), thePterocaulon group (3 genera), theLaggera group (6 genera), and thePluchea group (12 genera). All recognized genera are described and most genera are supplied with taxonomical notes including comments on their taxonomic status. Genera such asBlumea, Pluchea, andEpaltes are demonstrated to be unnatural assemblages.Monarrhenus andTessaria are both closely related to thePluchea complex. The old generic nameLitogyne Harv. has been taken up for one species ofEpaltes, the genusRhodogeron is reduced to a synonym ofSachsia, and the following new combinations are made;Litogyne gariepina (DC.)A. Anderb., andSachsia coronopifolia (Griseb.)A. Anderb.     

Cytotaxonomic analysis of the Himalayan species of the genusTorilis (Apiaceae)

Chromosome studies of four HimalayanTorilis species reveal a remarkable interand intraspecific differentiation of chromosome numbers and karyotypes:T. arvensis (2n = 12),T. leptophylla (2n = 12),T. Stocksiana (2n = 36) andT. japonica (2n = 16). Base numbers inTorilis are x = 6, 8, 9 and 11.     

A cladistic analysis of the tribeAstereae (Asteraceae) with notes on their evolution and subtribal classification

TheAstereae were surveyed and the genera arranged in 23 informal groups. The generic groups were used to sample representative genera for a cladistic analysis based on morphological characters. The resulting cladogram was used for discussion of evolution and subtribal classification within the tribe. The lower basic chromosome numbers x = 4, 5, 6, and 8 are interpreted as reductions from a primitive x = 9. The subtribeGrangeinae occupies a phylogenetically basal position as sister group to the rest of the tribe. This may be divided into two large groups, largely corresponding to the homochromousSolidagininae and to the heterochromousAsterinae sensu lato, i.e. including theBellidinae, Hinterhuberinae, Conyzinae, andBaccharidinae. The latter four subtribes are derived within theAsterinae, and hence reduced to synonymy. Several intercontinental relationships indicate that a geographical subdivision of the tribe should be avoided, although in our analysis most of the groups proved to be restricted to one of five major regions.     

The tribeSmyrnieae (Umbelliferae) in the light of serotaxonomical analysis

An immunochemical investigation of some Old-WorldUmbelliferae belonging to the tribeSmyrnieae in current classifications has clearly demonstrated that the genera of this tribe do not form a natural monophyletic taxon. The presence of a more or less deep groove on the commissural side of the seeds cannot be regarded as an essential marker of phylogenetic relationships within this family.     

A cladistic study of North AmericanCoreopsis (Asteraceae: Heliantheae)

A cladistic study of all 44 species of North AmericanCoreopsis was performed using 35 characters. The resulting cladogram indicated that all 11 sections are monophyletic. At the intersectional level, two lineages were revealed, one consisting of six sections occurring almost exclusively in Mexico and California, and another comprising five sections restricted largely to the eastern and southeastern United States. The cladogram is similar to phylogenies produced by less explicit methods but it differs in two major respects: the monotypic sect.Silphidium is placed with other sections from the southeastern United States rather than with Mexican sections, and sect.Anathysana from Mexico is more closely allied with the three California sections than with sect.Electra from Mexico.     

Pollen evolution and systematics inAnnonaceae with special reference to the disulcate Australian endemic genera

All genera ofAnnonaceae endemic in Australia (Ancana, Fitzalania, Haplostichanthus) show almost exactly the same type of disulcate (disulculate) pollen with intact exine extending over the sulci. Tetrad stages inHaplostichanthus andAncana reveal a latudinal subequatiorial orientation of the two sulci at the proximal hemisphere. Sometimes they fuse into a ±zonosulcate aperture.Fissistigma pollen grains are ±globose and have a flattened pole with a central elevation and a concentric groove, covered by a somewhat reduced exine. This palynological characters give further support for separating the generaAncana andFissistigma. Germination was observed inHaplostichanthus where the pollen tube emerges at one of the two sulci and inFissistigma where the flattened part breaks up during germination. The aperture types described here are obviously transitional stages between aperturate and inaperturate pollen grains and are discussed in regard to pollen evolution.     

Karyotaxonomical analysis in the genusAngelica (Umbelliferae)

Morphometric karyotype characters were studied in 25Angelica spp. (Umbelliferae, Apioideae) and in one species of the related genusTommasinia. For three species the chromosome numbers are new. In our study the majority of the species investigated are diploids with 2n = 22, some are tetraploids with 2n = 44 (for these tetraploids also diploid cytotypes are reported in the literature). Among the diploid species,A. miqueliana has a distinct karyotype consisting of submetacentric and acrocentric chromosomes only, the remaining diploids with 2n = 22 as well as tetraploids with 2n = 44 have rather symmetrical karyotypes, consisting of metacentric and submetacentric chromosomes. The very different chromosome number 2n = 28 has been found inA. gmelinii. Its karyotype includes two distinct groups of chromosomes: 8 pairs of rather large metacentrics and submetacentrics and 6 pairs of very short and asymmetrical chromosomes. Chromosome numbers and structures appear to be useful in the taxonomy of some intrageneric taxa inAngelica.     

The occurrence of vascular tracheids inBetula and some otherBetulaceae genera

The occurrence of vascular tracheids inBetula, Alnus, Carpinus andCorylus is reported. It is established that the cells are a consistent feature in early and late wood where they are associated with vessel elements in radial multiples. The possible function and taxonomic importance of these cells are briefly considered.     

Karyological studies of four genera of theChloranthaceae

Karyological observations on 7 species and 2 varieties of 4 genera belonging to theChloranthaceae demonstrate the presence of three basic chromosome numbers within the family, i.e., x = 8 (Hedyosmum), 13 (Ascarina) and 15 (Chloranthus, Sarcandra). The karyomorphology ofChloranthus andAscarina is similar, whereasSarcandra andHedyosmum display unique characteristics. Both karyological aspects, i.e., chromosome number and karyomorphology, demonstrate remarkable diversity ofChloranthaceae and complex relationships between its genera. A distant affinity betweenChloranthaceae andPiperales is suggested.Presented at the XV International Botanical Congress Yokohama 1993, Symposium on Relationships and Evolution of Primitive Angiosperms: Multidisciplinary Approaches.     

Tests of the accuracy of cladograms in Gilia (Polemoniaceae) and some other angiosperm genera

 This paper deals with the use of cladistic methods and cladograms in phylogeny reconstruction in plant groups containing numerous taxa. How accurate are the cladograms as to details? Accuracy tests at the level of details require an independently known phylogeny, which excludes most plant groups, but such tests can be carried out in domesticated and experimental plant groups which have documented pedigrees. Four such tests are known and are presented here: a new case in Gilia and three previously published cases in Avena, Hordeum, and Helianthus. The four cases include domesticated and experimental plants, use of morphological and molecular evidence, and presence of dichotomous as well as reticulate phylogenies. The cladograms of the four plant groups all differ in significant details from the known pedigrees. These results are discussed in relation to problems of interpretation of cladograms. Received March 21, 2000 Accepted August 16, 2001