Palynological study of Veronica Sect. Veronica and Sect. Veronicastrum (Scrophulariaceae) and its taxonomic significance

Pollen grains from 30 taxa, mainly from the Western Mediterranean area belonging to the perennial sections of the genus Veronica (Scrophulariaceae), were studied by LM and SEM. A close relationship was found between pollen size and ploidy level. Palynological characters cannot be regarded as essential taxonomic tools within the groups studied, although they have systematic value in some specific cases. The monophyly of Veronica subsect. Multiflorae is supported by a common and exclusive sculpture of exine. Delimitation of the genus is discussed and hypothetical evolutionary trends concerning pollen characters are addressed.     

A new species of Veronica (Scrophulariaceae) from Iran

Veronica daranica , a perennial herb growing in alpine regions of central Iran, is described and illustrated. The systematic position of this species and its closet relatives are discussed.     

Seed morphology in Veronica L. (Scrophulariaceae) from south-west Spain

Seeds of 12 species of Veronica from south-west Spain were examined with the scanning electron microscope and stereomicroscope. Based on seed shape, colour, cell shape and surface ornamentation, seven morphological types are recognized. Seeds of the different types are described, illustrated and compared. The distribution of seed types among taxa is given. A key to distinguish the different species or groups of species is provided.     

Non-volatile floral oils of Diascia spp. (Scrophulariaceae)

The floral oils of Diascia purpurea, Diascia vigilis, Diascia cordata, Diascia megathura, Diascia integerrima and Diascia barberae (Scrophulariaceae) were selectively collected from trichome elaiophores. The derivatized floral oils were analyzed by gas chromatography-mass spectrometry (GC-MS), whilst the underivatized samples were analysed by electrospray ionization mass spectrometry (ESI-MS) and Fourier-transform ion cyclotron resonance mass spectrometry (FTICR-MS). The most common constituents of the floral oils investigated are partially acetylated acylglycerols of (3R)-acetoxy fatty acids (C(14), C(16), and C(18)), as was proven with non-racemic synthetic reference samples. The importance of these oils for Rediviva bees is discussed in a co-evolutionary context.     

Host influence on floral variability inOrthocarpus densiflorus (Scrophulariaceae)

This study investigates the influence of host plants on the expression of floral variability in the hemiparasiteOrthocarpus densiflorus (Scrophulariaceae), to determine if interaction with host plants can facilitate the expression of normally hidden genes. Style extension inO. densiflorus is highly uniform in natural populations, with less than 1% of the individuals exhibiting an aberrant extended-style condition. Both seed treatment with giberellic acid and parasitic development with host plants significantly facilitates the expression of extended-style in progenies that show only minimal expression when grown autotrophically. Artificial selection experiments demonstrate the range of potential phenotypic variation to be under genetic control, and differentially influenced by the host environment. Although the biochemical basis of the host influence is unknown, some host plants produce stimuli that apparently disrupt buffering inO. densiflorus and expose normally unexpressed genetic variability to selection. If variation in other traits is similarly affected, the influence of host chemistry may provide parasitic plants with a greater than normal opportunity for rapid selectional change.     

A new species of Veronica L. (Scrophulariaceae) in the Cantabrian Range (Spain)

A new species of Veronica vadiniense in section Veronica is described from material from the Cantabrian Range, in the north-east of the province of León (north-west Spain). Several morphological characters related to stems, leaves, racemes, flowers and capsules are given, and also those related to the indumentum of different parts of the plant, especially calyx lobes and capsule. Indications about distribution and habitat with reference to bioclimatic, biogeographical and phytosociological aspects are provided. Diagnostic features are also given to enable comparison with the most similar species, Veronica officinalis and V. allionii , particularly in the indumentum and consistency of leaves, and in the indumentum and shape of the capsule.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 141 , 119–124.     

Ploidy differentiation and floral scent divergence in Buddleja macrostachya (Scrophulariaceae) complex

Floral scent has been suggested to be a key factor both in the diversification of the angiosperms, and the evolution and intra-specific differentiation of plants. In this study, we determined the ploidy and nuclear DNA content of B. macrostachya plants from 14 different populations across Yunnan using flow cytometry. The components of the floral scent were also identified using gas chromatography and mass spectrometry (GC-MS). Within these 14 populations, two new ploidy levels, tetraploid (2n = 4x) and octaploid (2n = 8x) were detected and identified for the first time here. The mean 2C DNA content of the tetraploids ranged from 1.81 ± 0.01 to 1.92 ± 0.02 G, but was 3.52 ± 0.15 to 3.73 ± 0.04 G in the octaploids. In addition, thirty-two scent compounds were identified, most of which could be categorized into four major classes: fatty acid derivatives (49.60 ± 7.45%); benzenoids (21.24 ± 3.96%); monoterpenes (25.28 ± 3.70%) and sesquiterpenes (3.88 ± 1.05%). Both tetraploids and octaploids emitted large relative amounts of 4-hydroxy-4-methyl-2-pentanone (42.21 ± 3.52% and 21.57 ± 3.10%, respectively) and benzadehyde (20.42 ± 2.35% and 28.45 ± 2.37%, respectively). Multivariate analysis of floral scent chemistry revealed marked dissimilarity (49.49%) between tetraploids and octaploids, and 4-hydroxy-4-methyl-2-pentanone and benzadehyde contributed greatly to this divergence in chemical scent profile. Our results suggest that B. macrostachya is a species complex with four different ploidy levels (2n = 4x, 6x, 8x, 12x). We believe the complex is in a process of pollinator-mediated rapid divergence.     

Morphometric variation in theAlonsoa meridionalis complex (Scrophulariaceae)

Morphological field studies of 27 populations of theA. meridionalis complex were conducted in Ecuador. It is possible to distinguish four different form series by the position of the stamens in relation to the style. This trait was congruent with the overall morphometric variation, shown by the results of a canonical discriminant analysis (CDA). The taxonomy of the species complex is discussed based upon the results of the CDA. The degree of outcrossing varied in different form series, from a comparatively high degree of selfing to predominantly outcrossing, as indicated by the variation within relative to among populations. This is probably due to the varying potentials for self-deposition owing to differences in the degree of herkogamy.     

Comparison of floral properties and breeding system in dimorphic Buddleja delavayi (Scrophulariaceae)

In this study, floral color, scent composition and emission rate, nectar property, pollinators, and breeding system of dimorphic Buddleja delavayi Gagnep. were investigated. Flower color of B. delavayi was determined using a standard color chart and spectrophotometer, and two distinct color polymorphisms were observed having purple or white flowers. Floral scents of B. delavayi were collected using dynamic headspace adsorption and identified with coupled gas chromatography and mass spectrometry. In total, 28 compounds were identified from the flowers of B. delavayi. The identified scents were divided into three chemical classes based on their biosynthetic origin: terpenes, fatty acid derivatives, and benzenoids. The scent profiles in all individuals were dominated by a few components, such as lilac aldehyde and alcohol, 4-oxoisophorone, benaldehyde, and oxoisophorone oxide. Floral scent composition (benzenoids and terpenes) showed a significant difference between white and purple flower morphs. Flower color–flower scent associations in B. delavayi were identified with two distinct scent profiles in the two color phenotypes. The studies of other floral characteristics (nectar, floral visitors, breeding system, and fruit set) indicated that floral scent emission rate, nectar volume, visitor visitation frequency, and natural fruit set were not significantly different between the two flower color morphs. Bagging experiments revealed that seed production of B. delavayi is dependent mainly on honeybee Apis cerana. Lastly, this study implies that dimorphic floral color in B. delavayi may have been maintained by floral visitors and nectar guide color.     

Comparison of floral scent between and within Buddleja fallowiana and Buddleja officinalis (Scrophulariaceae)

Floral scents are important olfactory signals for communication between plants and pollinators. Several studies have focused on inter-specific variation of floral scents, but little is known about the intra-specific variation, especially in some polychromic species. In this study, we investigated the floral scent compositions of Buddleja fallowiana and Buddleja officinalis in situ by dynamic headspace collection and coupled GC–MS. Variations of scent compositions within and between populations as well as among species were compared. In spite of substantial intra- and inter-population variability, B. fallowiana and B. officinalis were clearly differentiated in their scent profiles. In B. fallowiana, obvious differentiation was found between studied populations, while all investigated populations in B. officinalis are part of a metapopulation. These high intra-specific variations are discussed in relation to the introgression through hybridization and founder effects from different populations.     

Comparative analysis of late floral development and mating-system evolution in tribe Collinsieae (Scrophulariaceae s.l.)

Species of Collinsia and Tonella, the two sister genera of self-compatible annuals that constitute tribe Collinsieae, show extensive variation in floral size and morphology and in patterns of stamen and style elongation during the life of the flower (anthesis). We used a nuclear ribosomal ITS phylogeny, independent contrasts, and phylogenetically corrected path analysis to explore the patterns of covariance of the developmental and morphological traits potentially influencing mating system. Large-flowered taxa maintain herkogamy (spatial separation of anthers and stigmas) early in anthesis by differential elongation of staminal filaments, which positions each of the four anthers at the tip of the "keel" upon dehiscence. Small-flowered taxa do not show this pattern of filament elongation. The styles of large-flowered taxa elongate late in the 2-5 d of anthesis, resulting in late anther-stigma contact and delayed self-pollination. Anther-stigma contact and self-pollination occur early in anthesis in small-flowered species/populations. Thus, we found complex covariation of morphological and developmental traits that can be interpreted as the result of multitrait adaptation for early selfing and high levels of autogamy, delayed selfing and higher levels of outcrossing, or intermediate levels of outcrossing. Continuous variation in these traits suggests the operation of continuous variation in selective optima or the combined effects of divergent selection and phylogenetic inertia.     

Life history variation and infraspecific heterochrony inRhinanthus glacialis (Scrophulariaceae)

Comparative cultivation experiments were made with 14 populations of the annual, hemiparasitic speciesRhinanthus glacialis from seven different habitat types. Phenological data were recorded and plants from field samples and from corresponding experimental samples were morphologically analysed.There are up to ten weeks difference in the start of flowering between means of the extreme experimental populations. Flowering time variation correlates with the number of internodes and also with most of the other morphological characters. Flowering time also shows close relationships to different grassland types and the examined populations appear to be well-adapted to the environmental conditions in natural or man-influenced grassland types as far as flowering time is concerned. The number of internodes is mostly insensitive to the applied experimental influences. The rate of internode production is constant. Trade-offs are suggested for some morphological traits (i.e., few internodes with few branches and thus few flowers as trade-off for early flowering). — Previous studies of life history variation based on population data have not been incorporated into the theory of heterochrony. The pattern of life history variation of populations ofR. glacialis together with information about morphology, ecology, and phylogeny suggests that some variants have evolved from ancestors via heterochronic processes. Earlier flowering populations from montane hay meadows, litter meadows, and dry meadows belong to paedomorphic variants. These have fewer internodes and branches as well as reduced height in comparison with the suggested ancestor. Later flowering populations from subalpine limestone grassland belong to a peramorphic variant with more internodes, more branches, and taller stems in comparison with the suggested ancestor.     

Paraphyly of Veronica (Veroniceae; Scrophulariaceae): Evidence from the Internal Transcribed Spacer (ITS) Sequences of Nuclear Ribosomal DNA

Veronica (Veroniceae; Scrophulariaceae) and segregated genera, such as Hebe from New Zealand has been debated intensively in the past. We conducted an analysis of sequence data from the internal transcribed spacer region of nuclear ribosomal DNA (ITS) to evaluate the validity of segregate genera and the monophyly of Veronica. According to the results presented here, Veronica is paraphyletic, with the Hebe complex, Synthyris, and Paederota nested within the larger Veronica clade. Pseudolysimachion is in a basal polytomy of the expanded Veronica clade in the strict consensus tree and might be nested within Veronica as well. Clades within Veronica do not correspond to sections traditionally recognized. This study provides a first estimation of the phylogeny of Veroniceae using molecular data and can serve as a starting point for future investigations of Veronica and relatives. Received 24 July 2000/ Accepted in revised form 19 October 2000     

Comparative floral development in Lardizabalaceae (Ranunculales)

Lardizabalaceae, one of seven families of Ranunculales, represent a monophyletic group. The family has functionally unisexual flowers with the organs in trimerous whorls, petaloid sepals and sometimes nectariferous petals. Among Ranunculales, Lardizabalaceae share several floral characters and climbing habit with Menispermaceae, but molecular analyses indicate that Circaeasteraceae and Lardizabalaceae form a strongly supported clade. Morphological and ontogenetic studies of flowers have proved to be a good complement to molecular data in clarifying relationships. Floral organogenesis has been studied in very few species of the family. This study investigates the comparative floral development of three species from three genera (Decaisnea, Akebia and Holboellia) of Lardizabalaceae using scanning electron microscopy. Flowers have a whorled phyllotaxis. Within each whorl, the organs are initiated either simultaneously or in a rapid spiral sequence. In Akebia, six sepals are initiated, but one to three sepals of the second whorl do not further develop. The presence of three sepals in Akebia is thus a developmentally secondary simplification. The petals (if present) are retarded in early developmental stages; stamens and petals are different in shape from the beginning of development. The retarded petals may not be derived from staminodes in Lardizabalaceae. © 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2011, 166 , 171–184.