Stoloniferous Species Research Articles

The ‘lawnification’ of Australia’s eastern grassy woodlands: the past, current and likely future spread of an invasive perennial grass, Bothriochloa pertusa

Many of today’s damaging invasive plants were intentionally introduced for pasture development and amenity. By examining the introduction history and consequent spread of these species, we can identify factors associated with their successful establishment and dominance. Using collated presence/absence and cover data, alongside a review of the literature and discussions with land managers, we present a comprehensive analysis of the introduction history and spread of the environmental and agricultural grassy weed, Bothriochloa pertusa (L.) A.Camus (Indian couch) throughout Queensland, Australia. Using this data, we also perform habitat suitability models to predict its potential distribution and local-scale cover across Queensland in relation to key environmental variables. We found that B. pertusa was introduced on multiple occasions and across a large area of Queensland, despite re-occurring doubts and poor evidence for its benefit to livestock production. Livestock grazing, associated disturbances (i.e. land clearing, soil erosion) and climatic extremes were commonly associated with its spread throughout the landscape. In 2020 the main area of B. pertusa invasion as indicated by occurrence records spanned 28,537,600 ha. Results from the habitat suitability models suggest the occurrence and local-scale cover of B. pertusa is largely determined by climate variables and the foliage projective cover of trees. Based on these results B. pertusa still has considerable capacity to spread and increase in dominance across many areas of Queensland, particularly further west and south of its current range. The introduction and spread history of B. pertusa suggests propagule pressure, traits, climate, land management and cultural perceptions are all key factors implicated in the spread of B. pertusa. Where B. pertusa has become dominant there has been a major shift in lifeform from native perennial tussock species to a grazing tolerant stoloniferous species. To slow this process of ‘lawnification’ we recommend more conservative grazing strategies and strategically selected protected areas to maintain cover of grazing sensitive native tussock grass species.

Effect of soil spatial configuration on Trifolium repens varies with resource amount.

Soil spatial heterogeneity involves nutrients being patchily distributed at a range of scales and is prevalent in natural habitats. However, little is known about the effect of soil spatial configurations at the small scale on plant foraging behavior and plant growth under different resource amounts. Here, we experimentally investigated how a stoloniferous species, Trifolium repens, responded to varied resource amounts and spatial configuration combinations. Plant foraging behavior (i.e., the orientation of the primary stolon, mean length of the primary stolon, foraging precision, and foraging scale) and plant growth (i.e., total biomass, root biomass, shoot biomass, and root/shoot) were compared among differently designed configurations of soil resources in different amounts. The relationships of foraging behavior and plant biomass were analyzed. The results showed that the effect of the spatial configuration of soil resources on Trifolium repens depended on the resource amount. Specifically, when the total resource amount was low, fragmented soil patches promoted root foraging and increased Trifolium repens plant biomass; however, when the total resource amount was high, the soil spatial configuration did not affect foraging behavior or plant growth. Our results also showed that plant growth was facilitated by root foraging scale to adapt to low resource amounts. We conclude that the spatial configuration of soil resources at small scales affects whole plant growth, which is mediated by a distinct foraging strategy. These findings contribute to a better understanding of how the growth strategy of clonal plants responds to heterogeneous environments caused by different resource amounts and its spatial configurations.

The hidden half of the fine root differentiation in herbs: nonacquisitive belowground organs determine fine‐root traits

Plants rely on roots for absorption of nutrients from the soil. Differences in traits of fine roots and of the root system in general thus underlie differences among individual species in their ability to live in habitats differing in nutrient status and interactions with other species. Here we examine to what extent structure of the root system is determined by whole‐plant parameters, namely the expected life span of the rooting units (either genetic individuals or ramets in clonally growing plants) and the type of belowground nonacquisitive organs such as rhizomes. By using phylogenetic comparative techniques we confirm the existence of two independent directions of variation in root traits, namely fast–slow continuum and cooperation continuum and show that the fast–slow continuum is associated with the increasing lifespan of the plant's rooting units (from annuals and stoloniferous species through rhizomatous species up to nonclonal perennial species). Lifespan of the rooting unit thus determines a range of root traits, namely root mass fraction (proportion of roots from the total biomass) and root tissue density. This shared continuum in root traits, life span of the rooting units and the type of belowground nonacquisitive organs is correlated with the environment where the species typically occur, with fast end (annual and stoloniferous species) occurring in productive and disturbed, and slow end (nonclonal perennials) in unproductive habitats. Further, clonal species have slightly shallower and thinner roots as their roots are relieved from the transport function which is served by horizontal stem‐derived organs (stolons and rhizomes). This confirms that plant lifespan and belowground nonacquisitive organs must be considered as determinants for (fine) root traits in herbs.

<strong>Taxonomy and nomenclature of the southern Malagasy <em>Kalanchoe peltigera</em>, with reference to <em>K. rosei</em> var. <em>seyrigii</em> (Crassulaceae subfam. Kalanchooideae)</strong>

The taxonomy and nomenclature of Kalanchoe peltigera (Crassulaceae subfam. Kalanchooideae) and K. rosei var. seyrigii, a long-overlooked name published in the 1940s, are evaluated with an aim to resolve the taxonomic status and affinities of K. peltigera, which was described in the mid-2000s. In particular, the taxonomic status of K. peltigera as an accepted species is examined in detail and verified based on a comparison with other known phyllo-bulbiliferous species of Kalanchoe i.e., those species that produce bulbils on the margins of their leaf blades typically between crenations, as opposed to flori-bulbiliferous, or stoloniferous species. We show that both K. peltigera and the original description of K. rosei var. seyrigii are based on collections made of a single species from locations in close proximity in southern Madagascar. Based on an examination of living material and type specimens, as well as other herbarium accessions, of which only a limited number exist, we conclude that K. peltigera and one of the two specimens cited when K. rosei var. seyrigii was described apply to the same species. However, despite its original description, the type of the name K. rosei var. seyrigii is that of the synonym it replaced, i.e., K. rosei subsp. serratifolia, a taxon less closely related to K. peltigera, and therefore the two names are not synonymous. A morphological evaluation suggests that K. rosei is likely to be sister to K. peltigera. The name K. peltigera is neotypified as its holotype is no longer extant.

The impact of livestock grazing on the evapotranspiration-vegetation biomass relationship in a Southern Hemisphere salt marsh, Buenos Aires (Argentina).

Among the ecosystem services provided by salt marshes is the use of their natural vegetation as pastures for livestock production. As a result, the prediction of biomass productivity can be of great interest for the sustainable management of these environments. Evapotranspiration is one of the variables most used to estimate the yield of green biomass in pastures and crops, which to date has not been examined for natural environments such as salt marshes. We studied the aboveground biomass and species cover variability for two categories (erect and sward plants) in three plots affected by low, moderate, and high cattle grazing. Erect biomass was associated only with Spartina densiflora while for sward plants it gathered a diverse set of prostrate and stoloniferous species with high seasonal turnover. The evapotranspiration was estimated with a coupled surface resistance-Penman-Monteith model developed for these environments. The biomass of the plant categories shows different growth response according to livestock impact. S. densiflora has a slow-growing response after cattle consumption, even with high evapotranspiration. On the other hand, sward plants respond with biomass overproduction to livestock consumption, and a significantly positive relationship to evapotranspiration rate.

Effect of clonal growth form on the relative performance of species in experimental communities over time

Due to competition for resources, the performance of plant species in communities is modified by traits affecting their efficiency in resource uptake and use. Clonal growth by stolons or rhizomes enables plants to spread laterally and to share resources among interconnected ramets; therefore, clonal growth represents an important trait that likely affects the competitive ability of species. We tested the effect of different clonal growth forms on the relative performance of plant species in communities of the Jena Biodiversity Experiment over a ten-year period. Clonal growth form did not have a significant effect on relative performance in early stages of the communities. Surprisingly, none of the clonal growth forms gained dominance over time, but the species with long rhizomes generally performed slightly better than the other species, particularly in communities of low diversity. The stoloniferous species performed better in communities with a higher proportion of nonclonals, suggesting complementarity of the light exploitation strategies of stoloniferous and nonclonal species. Our results show the importance of clonal growth traits for the competitive abilities of plants in the context of community development, species diversity and community composition, as well as the necessity of distinguishing among different clonal growth forms.

Suppression of Leaf Blade Development by BLADE-ON-PETIOLE Orthologs Is a Common Strategy for Underground Rhizome Growth.

Rhizomes are modified stems that grow horizontally underground in various perennial species, a growth habit that is advantageous for vigorous asexual proliferation. In Oryza longistaminata, a rhizomatous wild relative of cultivated rice (Oryza sativa), leaves in the aerial shoots consist of a distal leaf blade and a proximal leaf sheath [1]. Leaf blade formation is, however, suppressed in rhizome leaves. In O.sativa, BLADE-ON-PETIOLE (BOP) genes are the main regulators of proximal-distal leaf patterning [2]. During the juvenile phase of O.sativa, BOP expression is maintained at high levels by the small regulatory RNA microRNA156 (miR156), leading to formation of leaves consisting predominantly of the sheath. Here, we show that in O.longistaminata, high expression of BOPs caused by miR156 was responsible for suppression of the blade in rhizomes and that bop loss-of-function mutants produced leaves consisting of the leaf blade only. Rhizome growth in soil was also hampered in the mutants due to a severe reduction in rhizome tip stiffness. Leaf blade formation is also suppressed in the stolons of Zoysia matrella, a monocot species, and in the rhizomes of Houttuynia cordata, a dicot species, indicating that leaf blade suppression is widely conserved. We also show that strong expression of BOP homologs in both rhizome and stolon leaves rather than in aerial leaves is another conserved feature. We propose that suppression of the leaf blade by BOP is an evolutionary strategy that has been commonly recruited by both rhizomatous and stoloniferous species to establish their unique growth habit.

Sonerila janakiana sp. nov., a stoloniferous species of Melastomataceae from India

Sonerila janakiana, a new tuberous, scapigerous and stoloniferous species of Melastomataceae collected from exposed wet rocks of evergreen and semi evergreen forests in the Nilgiris and Wayanad districts of Tamil Nadu and Kerala states on the Western Ghats in India is described and illustrated. Apart from other characteristics, it is distinguished from all hitherto known species of the genus in India by having stolons and dimorphic leaves. The stolons produced from tubers terminate and develop into new tubers producing new plants.

Leaves of Vallisneria Finds Source to Anti Dermatitis: Enriching Wetland Ecosystem

The renaissances of phyto-medicines lead to a resolute search of potential medicinal plants worldwide. In this perspective, predominantly, terrestrial allelochemistry has been an imperative tool to evaluate the drug potentiality of a plant. However, in aquatic ecosphere, the pharmaceutical evaluation of the aquatic macrophytes is an emerging aspect. Our study seeks to explore the curative traits of the exotic macrophyte, Vallisneria spiralis L. (Hydrocharitaceae), a perennial stoloniferous species and a key ecological community in freshwater wetland ecosystem. It is commonly used as aquarium plant and inhabits both in lentic and lotic environment of tropical and sub-tropical regions worldwide. Being rapid colonizers of aquatic ecosystem, literature study states the leaves of the macrophyte can excrete special function groups that can absorb, filter and precipitate chemical compound of water and through the auxiliary function of the microorganism. Considering these significances, we have extracted the leaf leachates of Vallisneria in 80% ethanol which had been purified by solid-liquid extraction process and further crystallized and subjected to biochemical analysis viz; phenols, flavonoids and tannins followed by antioxidant scavenging and microbial screening. Further the isolated compound was subjected to Mass and Fourier Infra-red Spectrometry. Comprehensively, all the experimental assays infer that Vallisneria leaves contain bioactive compound with mol wt. m/z 359 structured with microbial growth inhibiting functional groups which were found fungicidal against Malassezia globosa - the dandruff causing dermatitis fungus.

Positive association between Bromelia balansae (Bromeliaceae) and tree seedlings on rocky outcrops of Atlantic forest

Abstract:Plant facilitation can improve the diversity of plant communities in several ecosystems, especially in stressful environments. The establishment of tree species on rocky outcrops can be limited by several biotic and abiotic factors. The richness and abundance of forest trees species on rocky outcrops surrounded by a large forest remnant in south Brazil were correlated with the cover of Bromelia balansae, a spiny stoloniferous species commonly occurring at forest–grassland transitions. Sixty plots were established on three flat rocky outcrops (20 in each). In each plot the coverage of bromeliads was estimated into three classes (0%, 1–50% and 51–100%) and all seedlings (individuals 10–30 cm in height) were counted and identified. ANOVAs with randomization tests were performed to establish the effect of different bromeliad cover classes on the richness and abundance of seedlings. The cover of bromeliads was positively related to the richness and abundance of young pioneer tree species. Evidence suggests that B. balansae can act as a nurse plant for tree seedlings, but manipulative experiments are needed to confirm this.

Flooding and fragment size interact to determine survival and regrowth after fragmentation in two stoloniferous Trifolium species.

Clonal plants, which reproduce by means of stolons and rhizomes, are common in frequently flooded habitats. Resilience to disturbance is an important trait enabling plants to survive in such highly disturbed habitats. Resource storage is thought to enable clonal plants to resume growth after clonal fragmentation caused by disturbance. Here we investigated if submergence prior to disturbance reduces survival and regrowth of clonal fragments and whether or not genotypes originating from highly disturbed riverine habitats are more resistant to mechanical disturbance than genotypes from less disturbed coastal dune slack habitats. We further tested if variation in survival and regrowth was affected by internode size. Clones from contrasting habitats of two closely related Trifolium species were first genotypically characterized by amplification fragment length polymorphism and then subjected to soil flooding and subsequent clonal fragmentation. These species differ with respect to their abundance in riverine and dune slack habitats, with Trifolium repens mainly occurring in riverine grasslands and Trifolium fragiferum in coastal dune slacks. Soil flooding decreased survival and regrowth by up to 80 %. Plants originating from riverine grasslands were less negatively affected by fragmentation than plants from dune slack habitats. Surprisingly, ramets did not always benefit from being attached to a larger internode, as internode size was often negatively correlated with survival after fragmentation. Regrowth, on the other hand, was generally positively correlated with internode size. These unexpected results indicate that there may be contrasting selection pressures on internode size in stoloniferous species growing in severely disturbed habitats.

Ecology and conservation of grassy wetlands dominated by spiny mud grass Pseudoraphis spinescens in the southern Murray–Darling Basin, Australia

ABSTRACT The distribution, ecosystem functions, conservation status and threatening processes of grassy wetlands are reviewed, with an emphasis on changes in flood regimes, water resource development and land use. The focus of the review is the ecology of spiny mud grass Pseudoraphis spinescens (R.Br.) Vickery, a C4 perennial aquatic grass. In Australia P. spinescens is a dominant species in grassy wetlands of the southern Murray–Darling Basin, the Wet–Dry Tropics and coastal New South Wales. Adapted to high irradiance and ambient temperatures, and to intermittent inundation for several months’ duration, it is a rapidly growing (> 20 mm d‐1), stoloniferous species, requiring prolonged, deep flooding interspersed with drying to achieve maximum growth and reproduction. Pseudoraphis spinescens can be considered an important species of grassy wetlands, providing food and habitat for waterfowl and other aquatic organisms through high primary productivity and nutrient cycling. Grassy wetlands in Australia are under threat from altered flood regimes, water resource development, grazing and land‐use change. The provision of flood regimes that most closely match plant‐specific water requirements represents the management action with the best prospect for the conservation of grassy wetlands on regulated rivers. A basic model for the water regime of P. spinescens grassy wetlands is presented to inform conservation and management, and stressing the need of such wetlands for large areas and rivers with high flow volumes that generate relatively deep prolonged flooding followed by drying out of the floodplain. Copyright © 2013 John Wiley & Sons, Ltd.

Systematics of the southern African genus <i>Ixia</i> (Iridaceae: Crocoideae): 4. Revision of sect. <i>Dichone</i>

The southern African genus Ixia L. comprises ± 90 species from the winter-rainfall zone of the subcontinent. Ixia sect. Dichone (Salisb. ex Baker) Goldblatt J.C.Manning, one of four sections in the genus and currently including 10 species and three varieties, is distinguished by the following floral characters: lower part of the perianth tube filiform and tightly clasping the style; filaments not decurrent; upper part of the perianth tube short to vestigial; style branches involute-tubular and stigmatic only at the tips; and so-called subdidymous anthers. We review the taxonomy of the section, providing complete descriptions and distribution maps, and a key to the species. I. amethystina Manning Goldblatt is recognized to be a later synonym of I. brevituba G.J.Lewis. Most collections currently included under that name represent another species, here described as I. rigida. We recognize five additional species in the section: early summer-blooming I. altissima from the Cedarberg; I. bifolia from the Caledon District; I. flagellaris, a stoloniferous species from the Cedarberg; I. simulans from the western Langeberg; and I. tenuis from the Piketberg. We also raise to species rank I. micrandra var. confusa and var. minor, as I. confusa and I. minor respectively. Foliar and associated floral variation in the widespread I. scillaris has led us to recognize two new subspecies among its northern populations, broad leaved subsp. latifolia and the dwarfed, smaller flowered subsp. toximontana; subsp. scillaris is restricted to the immediate southwestern Cape, from Darling to Somerset West. Sect. Dichone now has 17 species and two subspecies.

Plant invasiveness is not linked to the capacity of regeneration from small fragments: an experimental test with 39 stoloniferous species

Fragmentation and vegetative regenera- tion from small fragments may contribute to popula- tion expansion, dispersal and establishment of new populations of introduced plants. However, no study has systematically tested whether a high capacity of vegetative regeneration is associated with a high degree of invasiveness. For small single-node frag- ments, the presence of internodes may increase regen- eration capacity because internodes may store carbohydrates and proteins that can be used for regeneration. We conducted an experiment with 39 stoloniferous plant species to examine the regeneration capacity of small, single-node fragments with or without attached stolon internodes. We asked (1) whether the presence of stolon internodes increases regeneration from single-node fragments, (2) whether regeneration capacity differs between native and introduced species in China, and (3) whether regener- ation capacity is positively associated with plant invasiveness at a regional scale (within China) and at a global scale. Most species could regenerate from single-node fragments, and the presence of internodes increased regeneration rate and subsequent growth and/or asexual reproduction. Regeneration capacity varied greatly among species, but showed no relation- ship to invasiveness, either in China or globally. High regeneration capacity from small fragments may contribute to performance of clonal plants in general, but it does not appear to explain differences in invasiveness among stoloniferous clonal species.

Reproductive strategies may explain plant tolerance to inundation: A mesocosm experiment using six marsh species

We investigated the impact of inundation duration on sexual and asexual reproduction strategies in six hygrophilic angiosperm species (2 annuals – Ranunculus sardous and Ranunculus ophioglossifolius, 2 rhizomatous – Juncus articulatus and Eleocharis palustris, and 2 stoloniferous species – Glyceria fluitans and Agrostis stolonifera). Plant growth during three inundation durations (natural, +3 weeks, +6 weeks) was assessed in 20 mesocosms. Biomass and reproductive traits were measured at the onset of flowering and at seed set. The six species maintained or increased their total mass in response to increased inundation period, suggesting a good tolerance to inundation stress. No changes were recorded in flowering time for the five species that flowered. The two annual species increased the number of flowers and mass allocated to sexual reproduction with increased duration of inundation, promoting extensive seed production. The response was species-specific in perennial species with an either a positive or a negative Gaussian curve of both traits in response to the increased duration of inundation. The duration of inundation affected ramet production in all perennial species except A. stolonifera, promoting ramet production in two out of the three species. In all species except E. palustris, the length and number of stolons or rhizomes were maintained, suggesting the importance of these connections in the resistance of perennial plants to flooding stress. These species occurring in repeatedly inundated habitats thus appeared to be tolerant to long inundations thanks to both sexual reproduction and vegetative propagation.

Two new stoloniferous species ofViola(Violaceae) from China

Two new stoloniferous species of Viola (Violaceae) from southern China are described and illustrated. Viola nitida is recognizably different from V. fargesii as the plant is evergreen and glabrous throughout, the leaf blade adaxially nitid, base cuneate or shallowly cordate, and margin serrate. Viola maoershanensis is different from V. diffusa as the leaf blade is serrate, base cordate and not decurrent to petiole, the petiole wingless, the flowers larger, the petals bluish violet or pinkish white, and the lower petal obtuse at the apex. The chromosome numbers of the two new species were counted as 2n = 24 (V. nitida) and 2n = 44 (V. maoershanensis). The taxonomic positions of the two species are discussed. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 159, 349–356.

Responses of clonal architecture to experimental defoliation: a comparative study between ten grassland species

Clonal architecture may enable plants to effectively respond to environmental constraints but its role in plant tolerance to defoliation remains poorly documented. In several non-clonal species, modifications of plant architecture have been reported as a mechanism of plant tolerance to defoliation, yet this has been little studied in clonal plants. In a glasshouse experiment, five rhizomatous and five stoloniferous species of grazed pastures were subjected to three frequencies of defoliation in order to test two hypotheses. (1) We expected plant clonal response to defoliation to be either a more compact architecture (low clonal propagation, but high branching), or a more dispersed one (long-distance propagation and low branching). Such plastic adjustments of clonal architecture were assumed to be involved in tolerance to defoliation i.e. to promote genet performance in terms of biomass and number of ramets. (2) The response of clonal architecture to defoliation was expected to be dependent on the species and to be more plastic in stoloniferous than in rhizomatous species. Most genets of each species were tolerant to defoliation as they survived and developed in every treatment. Architectural modifications in response to defoliation did not match our predictions. Clonal growth was either maintained or reduced under defoliation. Relative growth rate (RGR) decreased in eight species, whereas defoliated genets of seven species produced as many ramets as control genets. Biomass allocation to ramet shoots remained stable for all but one species. In defoliated genets, the number and mean length of connections, and mean inter-ramet distance were equal to or lower than those in control genets. Four groups of species were distinguished according to their architectural response to defoliation and did not depend on the type of connections. We hypothesised that dense clonal architectures with low plasticity may be the most advantageous response in defoliated conditions such as in grazed pastures.

Effects of inoculation with native arbuscular mycorrhizal fungi on clonal growth of Potentilla reptans and Fragaria moschata (Rosaceae)

Many clonal plants live in symbiosis with ubiquitous arbuscular mycorrhizal (AM) fungi, however, little is known about their interaction with respect to clonal reproduction and resource acquisition. The effects of arbuscular mycorrhiza on the growth and intraclonal integration between ramets of two stoloniferous species were studied experimentally in a nutritionally homogenous soil environment. Two species coexisting at the same field site, Potentilla reptans and Fragaria moschata, were selected as model plants for the study. Pairs of their ramets were grown in neighbouring pots with each ramet rooted separately. Four inoculation treatments were established: (1) both mother and daughter ramets remained non-inoculated, (2) both ramets were inoculated with a mixture of three native AM fungi from the site of plant origin, (3) only mother or (4) daughter ramet was inoculated. The stolons connecting the ramets were either left intact or were disrupted. Despite the consistent increase in phosphorus concentrations in inoculated plants, a negative growth response of both plant species to inoculation with AM fungi was observed and inoculated ramets produced fewer stolons and fewer offspring ramets and had lower total shoot dry weights as compared to non-inoculated ones. A difference in the extent of the negative mycorrhizal growth response was recorded between mother and daughter ramets of P. reptans, with daughter ramets being more susceptible. Due to AM effect on ramet performance, and thereby on the source-sink relationship, inoculation also significantly influenced biomass allocation within clonal fragments. Physiological integration between mother and daughter ramets was observed when their root systems were heterogeneous in terms of AM colonization. These results hence indicate the potential of mycorrhizal fungi to impact clonal growth traits of stoloniferous plant species, with possible consequences for their population dynamics.

Effects of cell number and cell size on petiole length variation in a stoloniferous herb

In stoloniferous species, the length of petioles is of pivotal importance because it determines the position of leaf blades within the canopy. From a mechanistic perspective, two developmental processes, cell division and cell elongation, are responsible for the length of a given petiole. This study aimed at quantifying the relative contributions of cell division and cell elongation to genotypic and plastic variation in petiole length of the stoloniferous herb Trifolium repens. Thirty-four genotypes of T. repens were grown under high light conditions and simulated canopy shade. Cells were counted and their lengths measured on epidermal prints from fully grown petioles of leaves that had been initiated in the experimental light conditions. Cell number was the main trait explaining petiole length differences among genotypes grown under high light, while both cell number and length changed in response to shading. Our study revealed a strong negative correlation between shade-induced changes in cell number and cell length: genotypes that responded to shading by increasing cell numbers hardly changed in cell length, and vice versa. Our results suggest that genotypic and phenotypic variation in petiole length results from a complex interplay between the developmental processes of cell elongation and cell division.

Adaptive variation in physiological traits underpinning stem elongation responses among nodally-rooting stoloniferous herbs

For nodally-rooting stoloniferous herbs a close physiological link exists between the growth of nodal roots and development of shoot tissues of phytomers distal to them. Furthermore, in Trifolium, presence of nodal roots at phytomers proximal to the youngest nodal root on a stem influences the allocation of carbon along the stem when that stem encounters a patch preventing further formation of nodal roots. In this study six further phylogenetically and morphologically diverse stoloniferous species, selected so that they varied along the phalanx–guerrilla continuum (Acaena (Rosaceae), Leptinella (Asteraceae), Mentha (Lamiaceae), Vinca (Apocynaceae), Lamiastrum (Lamiaceae) and Glechoma (Lamiaceae)), were used to test the null hypothesis: that in all stoloniferous species the proportional allocation of carbon to the youngest nodal root decreases if proximally located roots are present when their stems extend into an environment preventing further nodal rooting. As Glechoma and Lamiastrum failed to change their proportional allocation to the youngest nodal root whilst the other five species varied their proportional allocation, with the species with shortest internodes (Acaena and Leptinella) changing the most, we reject this hypothesis. In addition, upon the transition to a dry environment, internode lengths in species with longer internodes (Glechoma and Lamiastrum) were markedly increased (doubled) whilst those in species with shorter internodes showed no response. We suggest this response is driven by apical bud tissues sensing changes in the humidity of their micro-environment and then modifying the length of internodes developing proximal to them. The extent of both these physiological responses correlated linearly with internode length of species (or position along the phalanx–guerrilla continuum), suggesting that these three traits were co-evolving, possibly in response to variation in grain of environmental heterogeneity, in such a way that the trade-off between the explorative and exploitive components of growth was underpinned and the performance of species in particular niches optimised as a result.