A cladistic analysis of Nassauvia Comm. ex Juss. (Asteraceae, Mutisieae) and related genera

FREIRE, S. E., CRISCI, J. V. & KATINAS, L., 1993. A cladistic analysis of Nassauvia Comm. ex Juss. (Asteraceae, Mutisieae) and related genera. Nassauvia and the most closely related genera Calopappus and Triptilion from the southern Andes and Patagonia of South America, form a monophyletic group diagnosed by the following synapomorphies: cypsela trichomes single two-celled, cypsela testa with strengthened cells, pollen grains spheroidal to spheroidal-oblate, colpi membrane with sexine processes, pappus bristles two to six, and pappus deciduous. Furthermore, Nassauvia, Triptilion, and Calopappus form a group with two other Andean genera, Moscharia and Polyachyrus, diagnosed by occurrence of pseudocephalia and a reduction in the number of flowers to five, three or one. A cladistic analysis of the group was undertaken using 35 characters from morphology, anatomy, and palynology. The monophyletic terminal taxa were the 38 species of Nassauvia, the genus Triptilion, the monotypic genus Calopappus, the genus Polyachyrus, and the genus Moscharia. Character polarity was based on outgroup comparison using Cephalopappus. The analysis resulted in 223 equally parsimonious cladograms, each with 70 steps and a consistency index of 0.57. A successive weighting procedure was applied, resulting in 15 cladograms with a consistency index of 0.82. Results of the cladistic analysis support most of the current systematic classification of Nassauvia, with three exceptions: (1) Nassauvia (excluding Calopappus) is paraphyletic; (2) section Masligophorus appears to be a polyphyletic group (N. pygmaea does not cluster with the remaining species of the section); (3) section Panargyrum (without N. lagascae= section Caloptilium) appears to be a paraphyletic group. The capitula arranged in cymose conflorescences in Triptilion are regarded as a primitive condition which gave rise to all stages present in Nassauvia (conflorescence spicate, pseudocephalium, capitula solitary). The capitula arranged in pseudocephalia in Moscharia and Polyachyrus are regarded as a parallel development to the pseudocephalium found in Nassauvia. Nassauvia, subgenus Strongyloma appears as the most primitive taxon, with its spicate conflorescence, whereas section Masligophorus with its solitary capitulum is thought-derived. These results correspond well with cytological data where species of the subgenus Strongyloma have n= 11 and the species of section Masligophorus are tetraploids (n = 22).     

Molecular phylogeny of <Emphasis Type="Italic">Nassauvia</Emphasis> (Asteraceae,Mutisieae) based on nrDNA ITS sequences

The phylogeny of the genus Nassauvia and closely related genera was reconstructed using sequences from the internal transcribed spacer regions (ITS) of nuclear ribosomal DNA. The genus Triptilion is nested within Nassauvia, making the latter genus paraphyletic. Neither of the two subgenera Nassauvia and Strongyloma is resolved as monophyletic, and none of the sections of subgenus Nassauvia is recovered as monophyletic. The evolution of the compound secondary inflorescences has been complex in Nassauvia, with the highly aggregated forms representing the original condition in the genus. However, the ancestral condition is equivocal in several clades, and there are alternative reconstructions for the gains–losses of the variously aggregated conditions. There has been at least one gain of solitary capitula in Nassauvia. The evolution of flavonoid chemistry has been complex in Nassauvia, and flavonoids are of limited phylogenetic-taxonomic utility in the genus. Gains–losses of flavonols occur only on terminals whereas changes in flavones and C-glycosyl flavones occur at various levels in the tree. Gains–losses of methylation of flavones and flavonols occur only on terminals.     

Systematic overview of Krigia (Asteraceae-Lactuceae)

Cytological and morphological variation among Krigia species is examined. Krigia exhibits a broad range of chromosome numbers including n = 4, 5, 6, 9, 10, 15, and 30. Section Krigia is characterized by reflexed phyllaries and a base chromosome number of x = 5, while section Cymbia is characterized by erect phyllaries and chromosome numbers of n = 4, 6, and 9. The micromorphological characteristics of achenes, pappus, styles, corolla, pollen, stomata, and trichomes are documented using scanning electron microscopy. Among these, the pappus shows the greatest diversity and three major types are identified: 1) a pappus of many bristles and scales, as in K. dandelion, K. montana, and K. biflora; 2) a pappus of five bristles and five scales, as in K. virginica and K. occidentalis; and 3) an absent or highly reduced pappus, as in the K. cespitosa complex and K. wrightii. Thirty-five cytological and morphological characters are subjected to phylogenetic analyses. The two sections, Krigia and Cymbia, form monophyletic lineages. Within section Krigia, the annual species, K. virginica, forms an independent clade, while the perennial species, K. dandelion, K. biflora, and K. montana, form a monophyletic clade. Krigia montana and K. biflora are identified as sister species and a hybrid between these has been identified. The hybrid is more similar morphologically to K. montana than K. biflora. Within section Cymbia, phylogenetic relationships among K. wrightii, K. occidentalis, and K. cespitosa are uncertain. Nine taxa of Krigia are herein recognized: K. dandelion, K. biflora, K. biflora var. viridis (comb. nov.), K. montana, K. virginica, K. wrightii (comb. nov.), K. occidentalis, K. cespitosa, and K. cespitosa f. gracilis (comb. nov.). Phylogenetic relationships among 12 taxa of Krigia species are compared using various combinations of morphology, chloroplast DNA, and nuclear ribosomal DNA data. Tree topologies from different combinations of data are largely congruent. The most resolved phylogenetic tree is obtained using the combined data from morphology, chloroplast DNA, and nuclear ribosomal DNA.     

Reinstatement of Ocyroe (Compositae: Astereae)

Nardophyllum armatum, a species from the Puna region of Argentina, Bolivia, and Chile is here transferred to genus Ocyroe, which in turn is resurrected from the synonymy under Nardophyllum. Ocyroe is characterized by thorny branches, discoid capitula, naked receptacles, glandular corollas with a globose swelling at the base, and a profuse 3- to 5-seriate pappus. The new combination Ocyroe armata and a lectotype for Dolichogyne armata are here presented.     

Comparative pappus micromorphology of edelweiss (Leontopodium,Gnaphalieae, Asteraceae) with implications for taxonomy,ecology and evolution

We analysed pappus characters in 31 of the c. 34 accepted Leontopodium spp. (edelweiss). Micromorphological pappus character states were useful for discriminating between individual species and intrageneric groups. The pappus differs in number, length, breadth, surface structure, colour and the tips of the bristles. Several features characterize single species, for example a unique fan‐like tip that is only found in L. franchetii. Leontopodium section Nobilia is supported by unusual pappus characters. Experimental evidence shows that the pappus of Leontopodium, previously thought to be caducous, is well suited for wind dispersal of the fruit. One clear trend is that species growing in sparsely vegetated, high‐altitude regions often have more numerous and longer pappus bristles, particularly on the female flowers.     

Four additive genes determining pappus part numbers inMicroseris annual hybrid C34 (Asteraceae/Lactuceae)

Microseris strain C34 is a hybrid between the Chilean speciesM. pygmaea (10 pappus parts) and the CalifornianM. bigelovii (5 pappus parts). The F1 specimen had from 5 to 10 pappus parts per achene with an average of 6. F2, F3 and F4 plants derived from this hybrid by spontaneous selfing show segregation for the average number of pappus parts. Four segregating unlinked genes could be demonstrated, each with an allele determining 5 pappus parts from thebigelovii parent, one with an allele determining 10 pappus parts, three with null alleles from thepygmaea parent. The expected average pappus part number is the arithmetic mean of the 5- and 10-determining factors. Considerable environmental and developmental influences, both random noise and systematic shifts, could be demonstrated to influence the phenotypic expression. The parallel hybrid strain B87 has two 10-alleles rather than one in itspygmaea genome. The evolution of the pappus part genes ofM. pygmaea from those of abigelovii-like ancestor seems to demand the concerted (non-independent) mutation of at least two genes.     

Single-gene heterozygotes derived from the polygenic pappus part system ofMicroseris hybrid C34 (Asteraceae—Lactuceae)

Microseris strain C34 is a hybrid between the Chilean speciesM. pygmaea (10 pappus parts) and the CalifornianM. bigelovii (5 pappus parts). The plants are propagated by selfing from the original hybrid specimen. Each plant has from 5 to 10 pappus parts per achene with an average value that is additively determined by four unlinked quantitatively acting genes. Single-gene heterozygote sublines have been obtained for two of these,pp-1 (shown to be linked to a modifier of acid phosphatase-1) andpp-4. Sublines homozygous for all four additive genes show residual genetic variation influencing pappus part number. At least one additional gene can be demonstrated by its linkage with leucine aminopeptidase-1. Lines for the further characterization of these hypostatic genes are selected.     

Pappus part number in annual species ofMicroseris (Compositae,Cichoriaceae)

All North American annual species of the genusMicroseris have a five-part pappus, the one South American annual,M. pygmaea, has ten pappus parts. The pappus develops over a constant number of ten provascular bundles with or without inhibition between alternate sites of pappus development. Each natural population contains a predictable proportion of achenes with aberrant pappus part numbers. Hybridization betweenM. bigelovii (5 parts) andM. pygmaea results in F 1 and F 2 plants with many aberrant achenes. In each plant either five or ten can be shown to be the basic number with aberrant numbers following a Poisson distribution for numbers added to 5 or deleted from 10. Occasional plants show no basic number but have a random distribution of numbers about an intermediate mean. The evolutionary genetics of this character is discussed.     

A second marker enzyme in the genetics of pappus part numbers inMicroseris hybrid B87 (Asteraceae,Lactuceae)

CrossingMicroseris pygmaea (10 pappus parts) withM. bigelovii (5 pappus parts) results in hybrids with variable pappus part numbers between 5 and 10. Previous work has shown that a system of four additively acting genes determines the average pappus part numbers of these hybrids. In hybrid B87 two genes have a 10-determining and a 5-determining allele each, two others a 5-determining and a null (inactive or missing) allele. Genetic linkage of one of the latter with the enzyme geneEsterase-1 and the leaf shape genespatulate leaves has been demonstrated. Here we demonstrate linkage between one of the two 10-determining genes and the enzyme locusEsterase- Y/B. The genotypes in the pappus part system of many specimens can now be fully determined. This is a major advance for the analysis of the evolution of this additive polygenic system.Genetics of Pappus Part Numbers inMicroseris Hybrid B87, II.—Part I:Bachmann & al. 1981.     

Stephanbeckia plumosa (Liabeae: Compositae): A new genus and species from southern Bolivia

Material from southern Bolivia, recently collected by Stephan Beck, is described as a new genus and species, Stephanbeckia plumosa (Compositae: Liabeae). Both morphological and molecular data place the genus in the broadly interpreted subtribe Paranepheliinae, but clearly distinct from other members. It differs morphologically by its small size, deciduous plumose pappus, lack of paleae, and compressed bicostate achenes. A key to the genera of the Liabeae is provided.     

Galatella anatolica sp. nov. (Asteraceae: Astereae) from Osmaniye,Turkey

Galatella anatolica Hamzao?lu & Budak sp. nov. (Asteraceae), collected from Osmaniye (Turkey) is here described as a new species. It is similar to G. angustissima (Tausch) Novopokr. in general habit. Both have stems with few branches and 1‐veined middle leaves, but are distinguished by involucral features, series of phyllaries, and lengths of disc florets, achenes and pappus.     

Variability of the inflorescence ofMicroseris laciniata (Compositae: Cichorieae)

Quantitative characters of the flowering head of a garden population ofMicroseris laciniata were scored during the second, third, and fourth season of growth. Number of achenes per head, number of phyllaries per head and the average number of pappus parts per achene in single heads show significant plant to plant variation. Achenes per head and pappus parts per achene were scored in identical plants in two subsequent seasons. The number of pappus parts per achene varies freely between five and ten. This contrasts with annual species ofMicroseris in which either five or ten pappus parts are found, depending on the species. In spite of a clear plant-specific average of pappus parts, both high and low pappus part determination can be demonstrated in all specimens. The number of pappus parts depends on the position of an achene on the receptacle, marginal achenes usually having fewer pappus parts than central ones. This gradient is not closely correlated with the position of an achene on the genetic spiral.     

Genetic determination of pappus part number in the annual hybridMicroseris B 87 (Asteraceae—Lactuceae)

The ChileanMicroseris pygmaea has a ten-part paleaceous pappus while the CalifornianM. bigelovii has five pappus parts on each achene. Hybrids between the two species have between five and ten pappus parts with averages below 7.5. Hybrid B 87 has an F 1 average value of 6.7 pappus parts. 140 F 2 plants were raised from this hybrid, and 12 F 3 families were obtained by selfing from F 2 plants. One larger F 4 family has been raised. Pappus part number in all of these is still canalized between 5 and 10. Variation within these limits is genetically determined by a quantitatively acting polygenic system. Modeling of this system suggests that a minimum of four, but probably not many more, genes are involved. This opens the possibility of a complete genetic analysis of the system.     

A Triassic seed with an angiosperm‐like wind dispersal mechanism

The earliest record of a seed with a pappus‐like, parachute seed dispersal mechanism, Edenia villisperma gen. et sp. nov., is described from the Upper Triassic of the eastern United States. The seed is small and roughly triangular. Clusters of long hairs emerge from a whorl of at least five circular scars just below the proximal end. This morphology indicates that the hair clusters represent modified lateral structures similar to the pappus of several eudicot angiosperm groups, but probably representing a case of convergent evolution of a similar structure in a gymnosperm. The seeds are usually found isolated, but one specimen indicates that they were born tightly packed together on an axis. A few earlier records exist of dispersal hairs, but this is the first clearly indicating a pappus‐like structure. Although the exact affinities of Edenia are uncertain, this seed demonstrates that plants with highly advanced wind dispersal mechanisms occurred at least 55 million years earlier than previously thought.     

Ligularia zhengyiana sp. nov. (Asteraceae) from the Hubei Province,China

The new species Ligularia zhengyiana from the Hubei Province, China, is described and illustrated. It is characterized by dense blackish purple pilose hairs on the stems and by coarsely triangular‐dentate leaves. Ligularia zhengyiana is similar to L. fischeri (Ledeb.) Turcz., but L. zhengyiana has dense long blackish purple hairs on stems, while L. fischeri is glabrous or has short yellowish‐brown hairs on stems. In addition, the pappus of L. zhengyiana is white, while that of L. fischeri is yellowish‐brown.     

HENRICKSONIA (ASTERACEAE-COREOPSIDINAE), A NEWLY DISCOVERED GENUS WITH A PALEACEOUS PAPPUS FROM NORTH-CENTRAL MEXICO

A new genus, Henricksonia, containing the single species H. mexicana, has been described from a locality in north-central Mexico. It is unique among the genera of the subtribe Coreopsidinae in possessing a pappus of well-developed scales such as frequently occurs in other subtribes of the Heliantheae. The discovery of four, previously uncollected, monotypic genera among several tribes of the Asteraceae from this region over the past several years suggests that the area is a primary center of diversification for this large family.     

Genetic and Non-genetic Variation in the Number of Pappus Parts in Microseris douglasii Strain D37 (Asteraceae, Lactuceae)

The pappus of the annual species of Microseris usually consistsof a constant number of five paleaceous, awn-tipped scales.In some populations of Microseris douglasii, plants with variablenumbers of pappus parts, always five or fewer, are frequent.Here we study inbred lines derived from a plant with an averageof slightly less than five pappus parts (strain D40), from aplant with an average near three pappus parts (strain B14),and from F2 plants of a hybrid (D37) between these two strains.The average deviation from five pappus parts is subject to varioussources of non-genetic variation. The peripheral achenes ineach head have more pappus parts than the central ones, andthe overall average number decreases in later-formed capitulaof a plant. Both effects are strongly affected by environmentalfactors. Against this background, we show (polygenic) geneticvariation for the average deviation from five, and additionalheritable differences in the strength of the gradient in pappuspart numbers from the periphery to the centre of the capitulum,while the decrease of pappus part numbers in later-formed capitulais essentially identical in both parental strains, even in itsresponse to environmental factors. Visible phenotypic variationdue to all sources decreases as the average nears a constantnumber of five pappus parts Asteraceae, canalized characters, developmental genetics, inflorescence, Lactuceae, Microseris douglasii, phenotypic plasticity     

Phylogenetic relationships of JapaneseAster (Asteraceae, Astereae) sensu lato based on chloroplast-DNA restriction site mutations

RFLPs of cpDNA were examined for 18 species ofAster, six species ofKalimeris, two species ofMiyamayomena and one species and one variety ofHeteropappus from Japan, using 16 restriction endonucleases. Approximately 275 restriction sites were surveyed, and a total of 74 restriction site mutations was detected, and 31 of these were phylogenetically informative. Sixteen most parsimonious trees constructed from Wagner parsimony analysis indicated the polyphyly ofKalimeris andMiyamayomena sensu Kitamura;K. miqueliana belongs to a different clade from the remaining species ofKalimeris, and two species ofMiyamayomena did not make a single clade. This result suggests that the shortening or loss of pappus have happened parallelly in different evolutionary lineages. We must be careful to assess the pappus character in taxonomy and phylogeny, and it is desirable to examine their phylogenetic relationships using a molecular data.     

Reproductive features of Celmisia species (Asteraceae) in relation to altitude and geographical range in New Zealand

A range of seed and flower characters was examined in 37 species of the New Zealand genus Celmisia (Asteraceae) to determine whether there were any relationships between reproductive features and the geographic or altitudinal ranges of the species. Using published sources and herbarium material, flower attractiveness to pollinators was measured in terms of capitulum size and ray/disc length ratio. Dispersibility was measured in terms of seed dry weight, seed terminal velocity, pappus/seed length ratio, and scape/leaf length ratio. Altitude (minimum and maximum) and geographic ranges (number of 1^o latitude x 1^o longitude squares occupied) were obtained from published sources. A multivariate principal components analysis using 12 morphological characters revealed the presence of five groups of species differing in capitulum size, seed weight, pappus length, number of pappus bristles, leaf length and scape length. Linear regressions showed that altitude was significantly and negatively related to seed dry weight and capitulum size, and positively to scape/leaf length ratio. Geographic range is negatively related to capitulum size, and positively to ray/disc ratio and altitudinal range. Amongst the seed features measured, seed weight was the best predictor of terminal velocity (an inverse measure of dispersability), but lighter seeds also had a higher pappus/seed length ratio. The frequency distribution of the geographic ranges of the species is highly skewed, with many local species (86% occurring in 15 or fewer one‐degree squares) and very few common ones. Two species (C. gracilenta and C. graminifolia) are notably more common than all the others. A comparison of these species with the others shows that, on average, they have lighter seeds with more bristles, taller scapes and higher ray/disc ratios, but have smaller capitula. The low geographic abundance of the rare species could not readily be attributed to any specific reproductive feature, possibly because of the multiple types of rarity represented within the genus.