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• Clonal growth of plants is attained by a number of morphologically different organs (e.g. stolons, rhizomes, and roots), which are not functionally equivalent. Consequently, these clonal growth organ (CGO) types can determine functional traits that are associated with clonality, although little is known about their evolutionary flexibility or the constraining role they play on clonal traits. • We investigated the rates of evolutionary change by which individual CGOs are acquired and lost using a set of 2652 species of Central European flora. Furthermore, we asked how these individual CGOs constrain functionally relevant clonal traits, such as lateral spread, number of offspring, and persistence of connections. • We show that plants can easily switch in evolution among individual types of CGO and between clonal and nonclonal habits. However, not all these transitions are equally probable. Namely, stem-based clonal growth and root-based clonal growth constitute evolutionarily separate forms of clonal growth. • Clonal traits are strongly constrained by individual CGO types. Specifically, fast lateral spread is attained by stolons or hypogeogenous rhizomes, and persistent connections are attained by all rhizome types. However, the ease with which clonal organs appear and disappear in evolution implies that plants can overcome these constraints by adjusting their morphologies.

Polyploidy is arguably the single most important genetic mechanism in plant speciation and diversification. It has been repeatedly suggested that polyploids show higher vegetative reproduction than diploids (to by-pass low fertility after the polyploidization), but there are no rigorous tests of it. Data were analysed by phylogenetic regressions of clonal growth parameters, and vegetative reproduction in culture on the ploidy status of a large set of species (approx. 900) from the Central European Angiosperm flora. Further, correlated evolution of ploidy and clonal traits was examined to determine whether or not polyploidy precedes vegetative reproduction. The analyses showed that polyploidy is strongly associated with vegetative reproduction, whereas diploids rely more on seed reproduction. The rate of polyploid speciation is strongly enhanced by the existence of vegetative reproduction (namely extensive lateral spread), whereas the converse is not true. These findings confirm the old hypothesis that polyploids can rely on vegetative reproduction which thus may save many incipient polyploids from extinction. A closer analysis also shows that the sequence of events begins with development of vegetative reproduction, which is then followed by polyploidy. Vegetative reproduction is thus likely to play an important role in polyploid speciation.

Clonal growth confers a number of benefits on plants, but involves some costs as well. We examined whether seed reproduction is reduced in clonal plants due to these costs. Further, we investigated whether this relationship differs for species with optima at stressful or low-productivity sites, as a possible indication that clonality acts as insurance against reduced seed reproduction in such conditions. We evaluated 472 species for which seed production per unit area had been determined, and employed this information together with data on seed mass, height at maturity, clonal traits and optimum habitat conditions (using Ellenberg indicator values). There was a strong hyperbolic relationship between seed output and seed mass, with a scaling coefficient of −1, indicative of a simple tradeoff relationship. We performed analyses both with and without taking phylogeny into account. Reproductive output (i.e. the product of seed output and seed size) of was lower in clonal than in non-clonal plants (in both with and without phylogeny incorporated in the analyses); within non-clonal species, it was high in annuals and monocarpic plants relative to nonclonal perennials. Reproductive output was lower in clonal plants with extensive lateral spread. This may be due to lower mortality of such plants, which should favor reduced reproductive output, but direct resource tradeoff may also be involved. Reproductive output in all clonal and non-clonal plants increased with the nutrient status and light level of the species' optimum, and decreased with moisture. Because the proportion of clonal plants in vegetation is known to decrease along the same gradients, we can infer that as sexual reproduction becomes increasingly difficult in terms of these characteristics, clonal plants may capitalize on their capacity to bypass it. However, the relationships with habitat parameters disappeared in the phylogenetically corrected analysis, indicating that habitat preferences and reproductive output evolved together.

Plant nuclear genome size (GS) varies over three orders of magnitude and is correlated with cell size and growth rate. We explore whether these relationships can be owing to geometrical scaling constraints. These would produce an isometric GS–cell volume relationship, with the GS–cell diameter relationship with the exponent of 1/3. In the GS–cell division relationship, duration of processes limited by membrane transport would scale at the 1/3 exponent, whereas those limited by metabolism would show no relationship. We tested these predictions by estimating scaling exponents from 11 published datasets on differentiated and meristematic cells in diploid herbaceous plants. We found scaling of GS–cell size to almost perfectly match the prediction. The scaling exponent of the relationship between GS and cell cycle duration did not match the prediction. However, this relationship consists of two components: (i) S phase duration, which depends on GS, and has the predicted 1/3 exponent, and (ii) a GS-independent threshold reflecting the duration of the G1 and G2 phases. The matches we found for the relationships between GS and both cell size and S phase duration are signatures of geometrical scaling. We propose that a similar approach can be used to examine GS effects at tissue and whole plant levels.

In angiosperms, herbs evolved from ancestral woody growth form. A number of hypotheses on what was the driver of their evolution have been proposed, but none of them has received clear support so far. We are putting forward a new hypothesis that an important advantage of the herbaceous growth form lies in its greater capacity for plastic response to neighbour shading. Since most herbs form aboveground structures only for 1 year, they can respond to light heterogeneity more plastically than woody plants with long-living structures which need to pursue long-term goals such as stability and upward growth. To test the hypothesis, we carried out an experiment comparing plastic response to directional green shading of 21 species of young herbaceous and woody plants. We measured change of their tilt and length and compared it between herbs and woody plants using phylogenetic techniques. Both herbs and woody plants in our experiment responded to directed green shading by growing away from the shading plastic film. Overall response of herbs was, in agreement with the hypothesis, slightly stronger than response of woody plants, although there was high interspecific variation. The data indicate that herbs indeed have greater plasticity of stem growth in response to neighbour shading than woody plants, although the overall difference is not very strong. This capacity for plastic response might have played a role as one of the drivers of the evolution of the herbaceous growth form.

Patterns of clonal growth and their controls on the level of individuals have been studied thoroughly, but little is known about the actual clonal mobility of plant individuals in vegetation and about its role in generating vegetation patterns and influencing species coexistence. Current evidence shows that communities are composed of spatially nonmobile 'matrix-forming species' and mobile 'inter-matrix' species, while local between-species variation in clonal mobility has been shown to be positively correlated to small-scale richness. We identify two major gaps in the knowledge. (1) Clonal mobility has a strong species-specific component, but the existing information is mainly qualitative and describes the potential mobility of species the best. Also, species may respond by their clonal growth in a plastic way to some environmental stimuli, such as neighbors or abiotic environment, but this data comes almost exclusively from artificial conditions. We know very little of the actual spatial mobility of clonal plant individuals in the field and of the factors that determine it. (2) Theoretical research indicates that localized dispersal plays prime role in determination of community structure. While clonal mobility shares many important features with the seed dispersal, it also shows important differences to it, such as in dispersal kernel (non-monotonic in clonal dispersal), role of microsite limitation, and role of plasticity. We have little information how systematic are these differences, and whether these differences in dispersal can play any role in shaping community dynamics. We conclude that clonal mobility has an important role in structuring plant communities in a small scale and propose further studies to address specific mechanisms, as well as community context of evolution of clonality.

While plant roots respond consistently to nutrient availability under experimental conditions, our understanding of the role of such response in the field is hindered by poor knowledge of size and duration of nutrient patches there. In particular, knowledge of patch duration is critically important for understanding types of root response. We determined spatial and temporal variations in phosphate-P, nitrate-N and ammonium-N concentrations, and pH in an unproductive mountain meadow for which extensive data on fine-scale root distribution exist. We sampled soil solution weekly over 2.5 growing seasons using suction cups to in a hierarchical spatial design with the smallest grain of 3.3 cm. Overall concentrations of all studied nutrients were fairly low with occasional and short-term, but large-in-magnitude peaks, with no pronounced spatial or temporal structure at any scale. Temporal variation was much stronger than spatial variation, with both interannual differences and within-season differences playing a role. Phosphate-P was consistently highest in spring, whereas ammonium-N increased during summers. The ammonium-N, the major nitrogen source at the site, was negatively correlated with phosphate-P. Our data suggest that repeated sampling of soil solution in fixed positions is necessary to cover the entire extent of nutrient variation in the field. It shows that there are no stable nutrient patches at the fine scale, and the duration and size of nutrient patches are smaller than usual growth responses of roots. This implies that under such conditions, the best rooting strategy is homogeneous space occupation linked with fast physiological response to varying nutrient concentrations.

This dataset presents comprehensive and easy-to-use information on 29 functional traits of clonal growth, bud banks, and lifespan of members of the Central European flora. The source data were compiled from a number of published sources (see the reference file) and the authors' own observations or studies. In total, 2,909 species are included (2,745 herbs and 164 woody species), out of which 1,532 (i.e., 52.7% of total) are classified as possessing clonal growth organs (1,480, i.e., 53.9%, if woody plants are excluded). This provides a unique, and largely unexplored, set of traits of clonal growth that can be used in studies on comparative plant ecology, plant evolution, community assembly, and ecosystem functioning across the large flora of Central Europe. It can be directly imported into a number of programs and packages that perform trait-based and phylogenetic analyses aimed to answer a variety of open and pressing ecological questions.