Xanthorrhoea Preissii Research Articles

Induction of water repellency by leaves of contrasting Australian native species: effects of composition and heating

AimsThis study identifies the contribution of leaf matter from individual plant species on water repellency with a focus on the composition of organic compounds and the role of heat in releasing these compounds to soil.MethodsLeaf powder from four plant species (Banksia menziesii, Eucalyptus marginata, Allocasuarina fraseriana, Xanthorrhoea preissii) was mixed with acid-washed sand (AWS) under a range of temperatures and WR measured. Plant chemical composition was characterized by extraction of leaf powder and GC/MS analysis.ResultsIncreasing concentrations of plant powder mixed with AWS increased WR for three species; whereas for X. preissii there was no WR at any concentration. Heating increased WR for all species over the range of 30 to 120 °C. B. menziesii had the greatest WR, which was associated with the largest diversity of fatty acids and n-alcohols and highest concentration of alkanes, whereas X. preissii with the smallest WR had only C16 alcohol and C16 fatty acids at relatively low concentration.ConclusionsPhysically mixing leaf powder with AWS allows the contribution of different plant species on WR to be directly examined. WR appears to be related to differences in the concentrations and diversity of n-alcohols, n-fatty acids, and high n-alkanes in the leaves. The observed temperature effects on WR provide insights into the kinetics of release and dispersal of organic compounds from interstitial material.

Balgachernes occultus, a new genus and species of pseudoscorpion (Pseudoscorpiones: Chernetidae) associated with balga (Xanthorrhoea preissii) in south-western Australia, with remarks on Austrochernes and Troglochernes

Balgachernes occultus, a new genus and species of pseudoscorpion (Pseudoscorpiones: Chernetidae) associated with balga (Xanthorrhoea preissii) in south-western Australia, with remarks on Austrochernes and Troglochernes

Combustion temperatures and nutrient transfers when grasstrees burn

Fire controls the structure and functioning of many ecosystems, especially through its effects on biomass and nutrient cycling. Fire mineralizes soil nutrients and returns plant-locked nutrients to the soil. Nutrients are also lost from the ecosystem through release of particulates and volatile compounds during the fire, and later through surface transport and leaching when it rains. Xanthorrhoea preissii is the dominant grasstree in fire-prone southwestern Australia. Dead leaves are retained on the plant as a ‘skirt’ that envelopes the trunk. This makes the plants highly combustible and provides a unique opportunity to investigate burn temperatures and subsequent nutrient transfers to the soil and atmosphere.Temperatures of combustion and nutrient dynamics were determined for grasstrees in two vegetation types (woodland and forest) and at two fuel ages (5 and 15years postfire). During fire, dead leaves burnt at up to 1020°C (mean 496±240°C) and living leaves up to 740°C (mean 257±218°C), whereas the tightly packed juvenile leaves 15cm above the apical meristem only reached 85°C (mean 44±20°C). Dead leaves stored more nutrients than living, except for P and K that were leached out over time. Ash deposits were highest for B (37–52% of prefire mass), Mg (30–50%), Na (26–45%), Ca (36–44%), P (28–41%) and K (18–30%). Biomass and N deposits in ash were <2% of prefire values. Atmospheric export of N and S during fire ranged 67–82% of prefire mass (5-year sites) and 82–95% (15-year sites), mainly as a result of volatilization. Losses of K (4–55%), Mg (47–59%), Ca (39–61%), B (31–59%), and Na (35–69%) were likely to be via particulates. Loss of P (10–46%) was likely to be from a combination of particulates and volatiles, and was greater from the older fuel ages.In conclusion, the foliage of grasstrees is a significant repository of mineral nutrients and is almost completely incinerated by fire. Nevertheless, grasstrees are able to recover from fire as the apical meristem is well-protected from the heat. Less than half the store of nutrients is usually returned to the soil while more than half may be transferred to the atmosphere, representing a major source of nutrient loss from fire-impacted ecosystems. Longer intervals between fires may result in greater export of P from ecosystems already low in available P when fire does occur. The disparate effects of different fire intervals on ecosystem nutrient dynamics needs to be recognized in management of fire-prone vegetation.

Phytophthora boodjera sp. nov., a damping-off pathogen in production nurseries and from urban and natural landscapes, with an update on the status of P. alticola.

A new homothallic Phytophthora species, isolated in Western Australia (WA), is described as Phytophthora boodjera sp. nov. It produces persistent, papillate sporangia, oogonia with thick-walled oospores, and paragynous antheridia. Although morphologically similar to P. arenaria, phylogenetic analyses of the ITS, cox1, HSP90, β-tubulin and enolase gene regions revealed P. boodjera as a new species. In addition, P. boodjera has a higher optimal temperature for growth and a faster growth rate. Phytophthora boodjera has only recently been found in Western Australia and has mostly been isolated from dead and dying Eucalyptus seedlings in nurseries and from urban tree plantings, and occasionally from disturbed natural ecosystems. It is found in association with declining and dying Agonis flexuosa, Banksia media, B. grandis, Corymbia calophylla, Eucalyptus spp,. and Xanthorrhoea preissii. The status of P. alticola was also reviewed. The loss of all isolates associated with the original description except one; discrepancies in both sequence data and morphology of the remaining isolate with that presented the original description, and inconclusive holotype material places the status of this species in doubt.

One-step fitting of seed viability constants for two Australian plant species, Eucalyptus erythrocorys (Myrtaceae) and Xanthorrhoea preissii (Xanthorrhoeacea)

Long-term ex-situ seed storage under controlled conditions in gene banks has become an important tool for conserving threatened Australian plants; however, there is scant information about the seed longevity of most species. The aim of the present study was to determine whether the seed longevity of two contrasting Australian species could be modelled using the seed viability equation, and whether the universal temperature constants are applicable to these species. Seeds of Eucalyptus erythrocorys F.Muell. (Myrtaceae) and Xanthorrhoea preissii Endl. (Xanthorrhoeaceae) were aged at moisture contents ranging from 3.9 to 15.7% and temperatures between –20 and 60°C. Survival data were fitted to the seed viability equation in one step and the species constants for each species determined. Both E. erythrocorys and X. preissii seeds exhibited orthodox seed storage behaviour whose longevity could be modelled using the seed viability equation. The viability constants were KE = 8.81, CW = 4.97, CH = 0.0412 and CQ = 0.000379 for E. erythrocorys and KE = 8.77, CW = 5.29, CH = 0.0382 and CQ = 0.000473 for X. preissii. The universal temperature constants could not be used without a significant increase in error. The storage behaviour of these two Australian species is in keeping with that of orthodox species from around the world. Predictions are that E. erythrocorys will be long-lived under gene bank conditions, whereas X. preissii would be moderately long-lived. Current long-term gene bank storage conditions appear suitable for storage of these species; however, recommendations for short-term storage need to be re-evaluated.

Minerals in the ash of Australian native plants

This study characterized the ash of several Australian native plant species (silver wattle (Acacia retinodes), prickly moses (Acacia pulchella), wandoo/white gum (Eucalyptus wandoo), red gum or marri (Corymbia calophylla), grass tree (Xanthorrhoea preissii), jarrah (Eucalyptus marginata) and harsh hakea (Hakea prostrata)) and investigated the reactions of ash with soil. The ashes were alkaline with pH ranging from 12.3 to 13.8. and contained substantial amounts of plant nutrients. Amounts of calcium, magnesium, sodium or silicon varied depending on plant species and plant part. Many minor elements were also present including elements with no biological function. Available phosphorous (Colwell–P) in the ashes ranged from 30 to 199mg/kg. All elements were mostly present in crystalline compounds which were identified using XRD and SEM. Minerals present in ash included calcite (CaCO3), fairchildite (K2Ca(CO3)2),, nesquehonite (MgCO3.H2O), sylvite (KCl), lime (CaO), scolecite (CaAl2Si3O10.3(H2O)), quartz (SiO2) (derived from dust), portlandite (Ca(OH)2), periclase (MgO), and apatite, probably resembling hydroxyl-apatite (Ca5(PO4)3(OH)) and wilkeite (Ca5((P, S, Si)O4)3(OH,CO3)). Ash has important liming and fertilizer values and its effectiveness in these roles is a consequence of the properties of these minerals and their reaction with soil as was demonstrated in an ash plus soil incubation experiment.

Fire refugia: The mechanism governing animal survivorship within a highly flammable plant

AbstractIdentifying factors that influence the survival of individuals during disturbance is critical to understanding patterns of species reassembly within ecological communities. Although most studies of recovery of populations post‐burning acknowledge the potentially important contribution of animals surviving in situ, few have measured the effectiveness of refugia. This paper tests the hypothesis that some plants with tightly packed leaf‐bases provide a refuge for invertebrates during fire (even when the plants themselves burn) by using the highly flammable grass tree (Xanthorrhoeaceae: Xanthorrhoea). Invertebrates were sampled from four unburnt and five experimentally burnt grass trees (Xanthorrhoea preissii Endl.). Also collected were invertebrates fleeing during burning. The dataset comprises 949 specimens, representing 81 species from 18 orders, of which 749 individuals were from unburned plants. Slaters (Isopoda), silverfish (Thysanura), spiders (Araneae) and bugs (Hemiptera) dominated assemblages of the unburnt grass trees. Despite grass trees burning at temperatures of up to 515°C, some invertebrates survived in situ. Species‐specific microhabitat preferences within the plant appeared to influence survivorship. Species collected in the crown of unburned plants were found more often alive on burnt plants than species typically inhabiting the dead skirt of decaying leaves (thatch). We contend that the mechanism causing differential mortality is fire temperature. In the dead skirt, temperatures reached 225.33 ± 66.57°C. In contrast, a region of mild temperature (25.00 ± 3.54°C) persisted throughout burning near the apical meristem (within the crown). We conclude that grass trees are a potential reservoir from which invertebrates might re‐colonize recently burnt areas. However, owing to species‐specific microhabitat preferences and differential mortality across microhabitats, the invertebrate assemblage remaining in situ will be restricted taxonomically compared with the original grass tree fauna. Moreover, different fire regimes might mediate the effectiveness of grass trees as refugia. Finally, we argue that in situ survival of invertebrates within plants with tightly packed leaf‐bases is an unrecognized global phenomenon applicable to a wide array of plant taxa.

Phytophthora elongatasp. nov., a novel pathogen from theEucalyptus marginataforest of Western Australia

A novel homothallic species of Phytophthora producing semipapillate sporangia on sympodially branching sporangiophores, thick-walled oospores in smooth-walled oogonia, and paragynous antheridia is described here as Phytophthora elongata sp. nov. DNA sequencing of the internal transcribed spacer (ITS) DNA and coxI gene confirm P. elongata as a distinct species within ITS clade 2. It has been isolated in the northern jarrah forest of Western Australia (WA) from the roots and collars of dead and dying Eucalyptus marginata and occasionally Corymbia calophylla in rehabilitated bauxite mine pits. It has also been associated with dead and dying plants of several mid- and understorey species in the northern and southern jarrah forest—Banksia grandis, Leucopogon propinquus, Dryandra squarrosa and an Andersonia sp., as well as the monocotyledonous Xanthorrhoea preissii, X. gracilis and Patersonia xanthina. P. elongata has also been isolated from sandy soils and loams in Victoria in eastern Australia. The pathogenicity of P. elongata to E. marginata and Banksia spp. has been shown in this and earlier studies. Due to the uniformity of the ITS DNA and cox 1 sequence data in WA, P. elongata may be the result of a recent clonal introduction. More pathogenicity tests on a wider range of native plant species are needed to assess the host range of P. elongata and its invasive potential in WA.

The importance of grasstrees (Xanthorrhoea preissii) as habitat for mardo (Antechinus flavipes leucogaster) during post-fire recovery

Grasstrees (Xanthorrhoea) are an important structural component of many Australian ecosystems and also an important resource for many fauna species. Grasstrees have distinctive morphologies, with a crown of long thin leaves and skirts, the latter of which are accumulated dead leaves; both are incinerated by fire. This study determined the morphological features of Xanthorrhoea preissii, which change in response to fire from 6 months to 21 years post-burn. In addition, using radio-telemetry and spool-tracking, we determined that grasstrees are utilised as foraging and nesting resources for mardos (Antechinus flavipes leucogaster (Gray, 1841), Marsupialia: Dasyuridae). Recently burnt grasstrees (6 months post-burn) appeared not to be used by mardos at all. We found few mardos in these recently burnt sites, and the one individual we managed to track for 126 m utilised only a single grasstree: a 2-m-tall multiple-crowned grasstree that had escaped the fire was used as a nest site. For sites 5 years post-burn, mardos selectively utilised grasstrees with larger crown areas and those with a greater number of crowns compared with a random sample of available trees. At the 14-year post-burn sites, mardos still demonstrated some selection for grasstrees, although no specific single feature could be determined as most significant. We recorded humidity and temperature buffering effects in association with post-burn accumulation of grasstree skirt material and found that even dead grasstree ‘logs’ were an important resource for nests. We conclude that mardos utilise both live and dead grasstrees for foraging and nest sites, possibly owing to the availability of dense cover, a buffered microclimate, and potentially also food resources. Fire-management policies that promote habitat heterogeneity and retain several intact-skirted grasstrees within the landscape are likely to benefit mardos.

Grasstree (Xanthorrhoea preissii ) leaf growth in relation to season and water availability

Abstract Water stress usually arrests growth of even the most deep‐rooted species during summer drought in Mediterranean‐type climates. However, scant evidence suggests that grasstrees may represent an unusual exception. We used weather data and plant water potential to investigate the relationship between leaf growth and season in the grasstree, Xanthorrhoea preissii Endl. (Xanthorrhoeaceae). Leaf production in two contrasting habitats revealed continuous annual growth, oscillating between maximum rates (2.5–3.2 leaves/d) in late‐spring to autumn, to a minimum rate of 0.5 leaf/d during winter but never stopping. While the rate of leaf production during the fast‐growth season was positively correlated with temperature above 17–18°C, leaf elongation commenced substantially earlier in the year (from 12°C). Leaf water potentials cycled annually, with predawn readings commonly measured as zero during winter–spring and as low as −1.26 MPa during summer, but never indicating stress by exceeding the turgor loss point. Leaf death was synchronized with summer drought. The fast (summer) growth period was characterized by rapidly fluctuating leaf production, particularly in banksia woodland, where plant growth reliably responded quickly to &gt;18 mm of rainfall. Within 24 h of 59 mm of simulated rainfall, grasstrees in banksia woodland showed a marked increase in water potential, and leaf production reached 7.5 times the controls, confirming their capacity to respond to temporary spasmodic summer rains. Rainfall was the best climatic variable for predicting woodland grasstree leaf production during summer, whereas leaf production of forest grasstrees was most closely correlated with daylength. This plastic response of grasstrees between seasonal weather extremes is relatively rare among other mediterranean floras, and has implications for a recently proposed technique for ageing grasstrees.

Anomalies in grasstree fire history reconstructions for south‐western Australian vegetation

Abstract A new fire history for south‐western Australian sclerophyll forests was proposed recently based on grasstree (Xanthorrhoea preissii ) records that were interpreted to show a high frequency (3–5 years) ‘pre‐European burning regime’. Such a fire regime appears incompatible with the long‐term survival of many fire‐killed woody taxa. We investigated the local fire history in a small area of the northern sand‐plain shrub‐lands of south‐western Australia using 15 grasstrees, examining individual grasstree records in detail and comparing this with the decadal or averaged approach used in the original research, and with fire histories reconstructed from satellite images for the period since 1975. Results lead us to question the utility of the proposed grasstree fire history record as a tool for understanding past fire regimes for two reasons: First, inconsistencies in fire histories among individual grasstrees were considerable – some individuals were not burnt by known fires, while some apparently were burned many times during periods when others were not burned at all. Second, the grasstree record indicates a possible increase in patchiness of fires since 1930, while contemporary evidence and interpretations of the nature of Aboriginal (pre‐European) fire regimes would suggest the opposite. We believe that further research is needed to identify to what extent the grasstree method for reconstruction of fire histories can be used to re‐interpret how fire operated in many highly diverse ecosystems prior to European settlement of Australia.

Grasstree (Xanthorrhoea preissii) recovery after fire in two seasons and habitats

To distinguish fire-stimulated growth from the underlying growth patterns imposed by season, we measured leaf production of Xanthorrhoea preissii Endl. (Xanthorrhoeaceae). We compared unburnt with spring- and autumn-burnt sites in forest and woodland habitats. Following fire, X. preissii responded with accelerated leaf production, regardless of season. Rapid leaf production during the initial flush of growth was partly at the expense of starch reserves in the stem, at least after autumn fire. Although this initial flush was relatively short-lived after fire in both seasons (12–32 weeks), the effect of fire on leaf production was sustained for up to 20 months, accompanied by a significant reduction in leaf longevity. Mean maximum leaf production rate was higher for spring-burnt grasstrees (up to 6.1 leaves day–1) than those burnt in autumn (up to 4.5 leaves day–1), associated with seasonally optimal growing conditions in late spring–early summer. Similarly, the timing of autumn burns in relation to declining temperature with the approach of winter appeared to dictate how rapidly grasstrees recovered. The consequences of fire season could have implications for the reproductive success of X. preissii.

The western jewel butterfly ( Hypochrysops halyaetus): factors affecting adult butterfly distribution within native Banksia bushland in an urban setting

Adult western jewel butterflies Hypochrysops halyaetus Hewitson were studied in the Koondoola Regional Bushland Reserve on the northern outskirts of the Perth metropolitan area, Australia, in 1999. The butterfly is myrmecophilous, and the southern (Perth) form is considered to be ‘Vulnerable’. Butterfly dispersal, distribution, population size and habitat preferences were estimated using mark-recapture techniques. Butterflies were capable of moving large distances, and were widespread within the reserve but with a low density; however, one small physical area (80 × 20 m) contained a colony with large numbers of individuals. This colony, and an adjacent area of bush, was subject to a detailed microdistribution study: 1158 butterflies were marked within it over a 25-day period. The small size of the microdistribution study area compromised statistical independence assumptions: spatial autocorrelation was tested for and corrected, where appropriate, using a Markov-chain Monte-Carlo approach. Sex differences were evident in spatial autocorrelation: female data were not spatially autocorrelated, whilst male data was. The latter probably reflects the impact of the perching mode of mate location employed by males. Butterflies appeared to prefer rather degraded bush typical of a post fire/disturbance regime with high densities of the host plant Jacksonia sternbergiana. Males were positively correlated with the proportion of bare ground, again probably relating to preferred perching sites for mate location. Females were negatively correlated with Conospremum stoechadis probably indicating dense ground cover in degraded areas and Xanthorrhoea preissii probably an indicator at the site of more mature vegetation. Reserve management to improve vegetation quality may threaten the persistence of the butterfly within the reserve, whilst controlled burning to create even quite small new areas of habitat in an urban situation may be difficult to achieve. The creation of suitable habitat may be possible using mechanical means, provided the action of fire is not an essential component of habitat creation. As the western jewel appears to prefer degraded vegetation, it is possible that there may be opportunities for this species’ expansion within the urban environment provided that its mutualistic ant partner is also present.

Delta13C and water-use efficiency in Australian grasstrees and South African conifers over the last century.

Annual or biannual time courses of plant delta13C (delta13C(p)) over the last century (70-100 years) were recorded for leafbases of four grasstrees (Xanthorrhoea preissii) at four sites in mediterranean Australia and wood of four conifers (Widdringtonia cedarbergensis) at two sites in mediterranean South Africa. There was a strong downward trend of 2-5.5(per thousand ) from 1935 to 1940 to the present in the eight plants. Trends were more variable from 1900 to 1940 with plants at two sites of each species showing an upward trend of 1-2.5 per thousand. Accepting that delta13C of the air (delta13C(a)) fell by almost 2 per thousand over the last century, the ratio of leaf intercellular CO2 to atmospheric CO2 (c(i)/c(a)) rose in five plants and remained unchanged in three over that period. Changes in c(i)/c(a) rather than delta13C(a) were more closely correlated with changes in delta13C(p) and accounted for 6.7-71.8% (22.6 c(i)/c(a)) and 28.2-93.3% (delta13C(a)) of the variation in delta13C(p). We doubt that possible changing patterns of rainfall, water availability, temperature, shade, air pollution or clearing for agriculture have contributed to the overall trend for c(i)/c(a) to rise over time. Instead, we provide evidence (concentrations of Fe and Mn in the grasstree leafbases) that decreasing photosynthetic capacity associated with falling nutrient availability due to the reduced occurrence of fire may have contributed to rising c(i)/c(a). Intrinsic water-use efficiency (W(i)) as a function of (c(a)-c(i)) usually increased linearly over the period, with the two exceptions explained by their marked increase in c(i)/c(a). We conclude that grasstrees may provide equivalent delta13C(p )and W(i) data to long-lived conifers and that their interpretation requires a consideration of the causes of variation in both c(i)/c(a )and delta13C(a).

The anatomy and chemistry of the colour bands of grasstree stems (Xanthorrhoea preissii) used for plant age and fire history determination.

A new method of ageing and determining the fire history of grasstrees, based on colour bands running along the stem, has been developed. As part of our evaluation of the technique, we examined the structural and chemical basis of the colour differences. Exposed ends of the leaf bases are cream, brown and black, with the inner cortex, especially in the black leaf bases, being darker than the outer cortex. There was no structural difference between the three leaf base types. Tannin concentration increased from cream to brown to black leaf bases, and from the inner to outer cortex, and remained quite stable over many years. Both water-soluble and insoluble pigments contribute to the darkness of the black leaf bases. A hydrophobic naphthoquinone was present in the conducting tissues of the vascular bundles, and related naphthalene-derivatives were present in the surrounding tissues. We conclude that the colour differences between the leaf bases have a chemical basis that can be linked to environmental changes: tannin cells to phenological effects, and naphthalene-derivatives in the vascular core to the passage of fire.

Cryptobarsac rubriops, a new genus and species of selizine Flatidae (Hemiptera: Fulgoromorpha) from grasstrees (Xanthorrhoea preissii) in south Western Australia

– Cryptobarsac rubriops gen. et sp. nov. (Hemiptera: Fulgoroidea: Flatidae) is described from grasstrees, Xanthorrhoea preissii, in southwestern Western Australia. The genus is placed in the Tribe Selizini. The taxonomy, zoogeography and plant associations of the Australian Selizini are discussed.

Plant size and season of burn affect flowering and fruiting of the grasstree Xanthorrhoea preissii

AbstractFlowering and fruiting were assessed on 14 populations of the grasstree, Xanthorrhoea preissii Endl., occurring in the Darling Range near Perth, Western Australia. Independent of site, season of burn or year of flowering, there was a strong relationship between plant height, which varied from 0.1 to over 2 m, and the incidence of postfire flowering, which varied from 1% (winter burn) to 75% (summer burn) of grasstrees present. There was no relationship between inflorescence dimensions, or flower or fruit production on a spike basis, and plant size/age (height). When standardized for height, spring‐burnt populations produced 40% as many inflorescences as autumn‐burnt populations and 20% as many as summer‐burnt populations. Inflorescences produced by spring‐burnt plants were moderately smaller than those by summer–autumn‐burnt plants. Fruit density per spike in autumn‐burnt plants was 80% of that in spring–summer‐burnt plants. The net effect was an average of 70 000 fruits produced per 100 summer‐burnt plants, 22 000 in autumn‐burnt plants, and 14 000 in spring‐burnt plants. Ecophysiological explanations of these results and their implications for population dynamics have yet to be explored.

Plant size and season of burn affect flowering and fruiting of the grasstreeXanthorrhoea preissii

Plant size and season of burn affect flowering and fruiting of the grasstree<i>Xanthorrhoea preissii</i>

Phosphite concentration: its effect on phytotoxicity symptoms and colonisation by Phytophthora cinnamomi in three understorey species of Eucalyptus marginata forest

Pre-treatment of plants with foliar sprays of 0.2, 0.5 and 2% phosphite restricted colonisation by Phytophthora cinnamomi in inoculated stems of Adenanthos barbiger and Daviesia decurrens, and led to a reduction in the isolation of P. cinnamomi from these stems in comparison with unsprayed plants. In plants treated with 2% phosphite, P. cinnamomi was not isolated from D. decurrens but was isolated from 22% of the stems of A. barbiger. In Xanthorrhoea preissii, colonisation by, and isolation of, P. cinnamomi from inoculated roots was not significantly affected by pre-treatment of the foliage with 0.2, 0.5 and 2% phosphite. Very low concentrations of phosphite were detected in the roots of X. preissii (maximum mean of 2.2 μg/g dry weight), in comparison with the phosphite concentrations measured in the foliage of A. barbiger and D. decurrens plants treated with phosphite (maximum means of 80 and 871 μg/g dry weight, respectively). Treatment with 0.2% phosphite resulted in minimal phytotoxicity in each of the three species, whereas treatment with 2% phosphite led to the development of severe phytotoxicity symptoms. This study indicates that phosphite has potential for the management of P. cinnamomi in native plant communities.

Colletotrichum xanthorrhoeae sp. nov. on Xanthorrhoea in Western Australia

Colletotrichum xanthorrhoeae sp. nov. causes leaf spots on Xanthorrhoea preissii and X. platyphylla in south-western Western Australia.