CSIRO PUBLISHING Australian Journal of Botany, 2021, 69,30–44 https://doi.org/10.1071/BT20118

Controls on myxomycete and species assemblages

Peter Wellman

17 Warragamba Avenue, Duffy, ACT 2611, Australia. Email: [email protected]

Abstract. This paper uses data from previous worldwide myxomycete surveys to determine the controls on the occurrence of myxomycete species, and on species assemblages. The main findings are as follows. The effect of substrate pH can be modelled, in that each species has a preferred pH value relative to the mean of a survey; errors from the model are 0.2 pH units. The substrate physical properties, evaluated by subjective hardness, showed no correlation with pH measurements. Hence, myxomycete species seem to have distinct ecological niches in substrate, with preferred pH and preferred physical properties. Comparison of the species found from the liana stem substrate shows that the species association does not change within angiosperm forests. Further, the species association is the same as that found in other angiosperm litter substrates: twigs on trees or on the ground, and leaves. This and a previous finding are consistent with similar ecological environments around the world having the same myxomycete species association within sampling error. In mixed angiosperm forests around the world the pH of un-decayed wood is ~4.9, and for decayed wood and tree litter is ~6.5 in tropical latitudes, and ~5.5 at 35 latitude, so on decaying the change in pH varies with latitude.

Keywords: acidity, latitude, myxomycete, pH, plasmodial slime mould, species assemblages.

Received 11 September 2020, accepted 30 November 2020, published online 22 January 2021

Introduction substrate needs only ~30 diverse samples if five Petri dishes Myxomycetes (plasmodial slime moulds) are single celled are grown per sample (data of Wellman 2019; this paper). organisms in the phylum . Their life cycle has A large number of myxomycete moist-culture surveys have two feeding stages; a relatively small uninucleate phase, and a been carried out. In a great majority of the surveys the larger multinucleate plasmodium. The life cycle ends with a objective was to obtain a listing of the species on one or fruiting body which contains spores. When there is moisture more substrates, particularly the rare species. In many cases the myxomycetes feed mainly on bacteria, but otherwise they the surveys included an analysis of the completeness of the survive as dormant stages (microcysts, sclerotia, and spores). species list. Some of the major surveys have also recorded There are ~1000 species (Stephenson and Rojas 2017), with environmental parameters and analysed the correlation within almost all species identified from their fruiting bodies in terms the survey area between the myxomycete species and the of a morphological species concept. A summary of our present various environmental niches (e.g. Schnittler 2001). There knowledge of myxomycetes is provided by Stephenson and have been many comparisons of species assemblages using Rojas (2017). measures of diversity. Previous papers by Wellman (2016, Myxomycetes can be obtained in the fruiting stage either by 2019) have tackled some general topics using Australian data collecting naturally occurring fruiting bodies in the field, or by from the bark substrate: the number of species associations collecting substrates with resting phases and cultivating the over Australia; the nature of the species association substrates. It is not practical to address most of the subjects boundaries; the effects of pH on the productivity; the discussed in this paper by using the fruiting bodies collected in variation over Australia of productivity and family the field, because where myxomycete fruiting bodies are found dominance; and the typical growth and decay over is not necessarily where they have fed. The moist culture four weeks of a large mixed myxomycete ‘population’.This method of cultivation is relatively easy: it can be applied to any paper uses both Australian and overseas data to investigate organic matter; a sample can be collected over a large part of other general myxomycete ecological topics which affect the year; the relation between the number of fruit and the myxomycete species. These topics include: the extent of feeding source is known; and the number of common species species associations around the world, the effects of pH and on a single type of substrate is ~30, so a survey to determine substrate physical properties on a species, and the average the relative abundance of the common species of a type of change of substrate acidity with latitude.

Journal compilation CSIRO 2021 Open Access CC BY www.publish.csiro.au/journals/ajb Controls on myxomycete species and assemblages Australian Journal of Botany 31

The study of myxomycete growth controls is important wood. The samples were collected from indigenous and exotic both to understanding myxomycetes (plasmodial slime trees growing in the city of Canberra (35S, south-east moulds), and, because the cultivation of myxomycetes is so Australia). The exotic trees originated in other temperate easy, to providing important pointers to growth controls in climates. Small pieces of the samples materials were placed other simple organisms which are more difficult to study. The in small plastic cups, 20 mm of de-ionised water was added, related cellular slime moulds (Distyostelia) are the model the cups were left for 24 h, and then the pH of the water was organism for investigating the workings of a single cell. determined by a pH meter that had been calibrated by standard solutions.

Materials and methods Results The studies in this paper were initiated by a desire to compare the myxomycete species assemblage on Australian temperate Geographic extent of litter-substrate species assemblages liana substrates with the assemblage on tropical liana substrate. The aim of this study was to obtain the myxomycete species A temperate liana substrate survey was carried out as follows. assemblage for temperate rainforest liana stems, so the species The samples were collected near the coast in eastern New found could be compared with nine assemblages previously South Wales (NSW) at different months during the years reported on liana in the tropics. The results of the 10 available 2014–2018. They were selected from five areas over seven surveys are listed in Table 1 as columns 1–10, with the degrees of latitude to provide variety in location. They were temperate survey as column 3. The main difference in taken from 14 liana species and a wide range of families to species association between the temperate survey and provide variety in substrate pH and bark texture. In all species elsewhere is that in NSW Physarum oblatum is common, a section of the woody stem showed numerous wide water and the fusca is subspecies fusca not nigrescens. conduits. The liana samples were collected during a long The NSW data does not record tenerrima (which period of dry weather, so the myxomycete material should apparently does not occur in Australia), or Perichaena be in a resting phase when collected. The material cultivated dictyonema and Physarum didermoides. These differences for myxomycetes was liana stem sections ~20–45 mm long are minor. Column 3 was from the temperate forest (bark and wood). Most of the stem material was of small reported above, column 1 was sampled well above the diameter so the stem was cultivated whole, but a few stems, ground at the very top of the rainforest, column 9 samples with a diameter >8 mm, were cut lengthwise, and the half a cloud forest at 1300–2700 m altitude with liana stems having sections were cultivated with the bark uppermost. a thick epiphyte covering, and in other surveys the samples Myxomycete fruit were obtained by the moist culture were collected close to the ground near sea level. After method (Stephenson and Stempen 1994). For each sample allowing for the effect of sampling errors, there appears to five Petri dishes were cultivated, each dish 90 mm in diameter be no difference between the species assemblages of these 10 and 10 mm high. Filter paper was placed at the base of each surveys; that is, the surveys are consistent with a liana Petri dish, and sections of the stem were placed on this with the myxomycetes species association being uniform across stem sides touching, to fill the Petri dish. In order to obtain as angiosperm closed rainforest. If we take the species which many myxomycete species as possible in each Petri dish, the occur on three or more surveys as forming the liana species pieces of stem used sampled the range of stem diameter, assemblage, then this assemblage consists of 22 species, and degree of decay and bark texture. For each selected stem a they occur with an abundance of 6–160 parts per thousand (‰) portion was placed in each Petri dish. The Petri dishes were This species assembly is listed in Table 1,column19. half filled with ‘distilled’ water, left for 24 h and then the water Table 1, columns 1–20 list the published myxomycete was drained. The Petri dishes were then maintained at ~22Cin species assemblages for four types of litter substrates in diffuse natural light. Every week the dishes were inspected, angiosperm forests: dead liana stems on the vine; dead mature fruiting bodies removed for drying and study, and twigs on the ground; dead twigs still on the tree or shrub, Petri-dish moistness was maintained by adding drops of water. and mainly dead leaves on the ground. If there are any Any pieces of substrate with significant was discarded. differences between the species assemblages of the litter The duration of cultivation was 6–8 weeks. This procedure types, or at any particular location, then these differences aimed at getting a large diverse species assemblage and a large should show on the table. The table does not list species number of fruiting bodies so the relative productivity of occurring in total fewer than three times because these species could be better determined. The myxomycete species are too rare to help in any comparison. Column 20 fruiting bodies were identified mainly using Ing (1999), of the table shows the mean species assemblage for the Poulain et al.(2011) and Discover Life (see http:// additional three litter types combined. The dataset is not discoverlife.org). Appendix 1 lists for each sample the perfect, and interpretations of a species assemblage have to sample number, location, liana species, mean stem diameter take into account of a species having no records, or a very large and, when known, the pH of the stems. Appendix 2 lists the number of records due to the following factors. For some myxomycete species found, and for each species lists the surveys the number of records is small relative to the number records – sample number and the number of fruiting bodies. of species being considered, so strictly the survey is not large The new pH measurements reported in Appendix 3 were enough for the purpose. Some continents do not contain some made on four types of myxomycete substrates: liana stems; of the species on the list, explaining a survey’s absence of a partly decayed twigs on trees; decayed wood and non-decayed record. The sample area may be in a ‘swarm’ of one species, so 32 Australian Journal of Botany P. Wellman

Table 1. Myxomycete species assemblages on decayed tree parts Data reference: 1. Cedeño et al.(2014); 2. Stephenson et al.(2008); 3. Novozhilov et al.(2017a); 4. Schnittler et al.(2002); 5. Stephenson and Stephenson (2019); 6. Schnittler et al.(2006); 7. Novozhilov et al.(2017b);8.WrigleydeBasantaet al.(2008); 9. This paper; 10. Camino et al.(2008); 11. McHugh (2005); 12. Ko Ko et al.(2010). Type of litter: lt, twigs on ground; li, dead twigs on tree; ll, leaf litter on ground; #, lt+li+ll. Temperature: W, warm; C cool

Column 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Country Aus Aus Aus Mex Peru PR Cub Equ Equ Tha USA Cub Vie Vie Equ Ger Vie Rus Equ Chr Temperature W W C W W W W W C W C W W W C C W C C W Data reference 8 8 9 8 8 8 10 11 4 12 1 2 3 3 4 6 3 7 4 5 ‰‰A Type of litter li li li li li li li li li li lt lt lt la la la ll ll ll # li lt+la+ll

Arcyria afroalpina 13 29 1 cinerea 4 1 19 1 4 30 2 3 4 7 52 8 2 20 5 47 15 10 10 84 160 197 Arcyria denudata 12 2 2 1 1 1 6 6 Arcyria insignis 22 2 2 9 4 Arcyria pomiformis 21110412 Badhamia melanospora 41 11 0 Calomyxa metallica 4 191 Clastoderma debaryanum 11 252 76 14 22 arcyrionema 125 1311 1 2 1 4 115111 Comatricha elegans 3 565 Comatricha laxa 18 2 4 121247 Comatricha nigra 15 3 1 0 19 Comatricha pulchella 11141 366 Comatricha tenerrima 12 331 3 122 1 9289 Cribraria microcarpa 1 2 4 9 20 1 6 34 Cribraria violacea 1 1 1 3 1 1 2 7 10 1 12 15 25 Diderma effusum 1 5 2 1 4 29 3 41 2 58 Diderma hemisphaericum 1 2 2 2 1 4 35 11 19 anellus 1211352213 Didymium clavus 1311493 Didymium difforme 21 3 6 3 Didymium iridis 411 1113 111032 20154542 Didymium nigripes 1411329139 Didymium squamulosum 15 3 215 12 1 6 2334320 minutum 2 1 8 1 4 5 1 10 6 1 2 1 2 34 28 Hemitrichia pardina 1 1 1 2 1 1 11 2 Hemitrichia serpula 12 5 3 0 18 Lamproderma scintillans 2 16 9 37 0 39 Licea biforis 11 1 3 44 Licea operculata 17 12 210 Perichaena chrysosperma 2 2 2 2 1 1 2 18 5 2 29 18 8 11 10 26 94 Perichaena depressa 6 1 1 1 11 5 4 8 42 19 2 6 43 82 Perichaena dictyonema 11 3 1 2 31 174 Perichaena pedata 31 13 0 6 Perichaena vermicularis 1 4 5 1 122416 1132430 Physarum album 11 111 1546 Physarum bivalve 11 7 0 9 Physarum cinereum 131361213 Physarum compressum 2 9 2 292253 1 262 97714 Physarum decipiens 22345 Physarum didermoides 2221 2 152 Physarum gyrosum 14 11 0 Physarum leucophaeum 12 12 1 6 13 Physarum melleum 41 31 3 101110 Physarum oblatum 219 5 3456 Physarum pusillum 52317121415 22 7510 Physarum superbum 12 11 91 Physarum viride 11 921 412 Stemonitis flavogenita 26248 Stemonitis foliicola 23 6 24 0 3 13 1 5 1 5 10 1 10 19 2 7 4 49 55 Trichia munda 23144 Willkommlangea reticulata 14 2 1 2 172 Number of records 30 21 132 23 33 117 26 14 28 44 139 78 49 148 39 196 157 75 45 367 1000 1048

AThe Christmas Island values have been weighted by 1/3 to give reasonable weights to all datasets. Controls on myxomycete species and assemblages Australian Journal of Botany 33 thenumbersofonespeciesmaybeverylarge.Intermsofa some species in common. To be useful, the surveys should random sample some surveys err in collecting substrates of have at least six species with six or more records, so that for different tree species only in a small area, whereas other these species the mean pH is known with reasonable accuracy. surveys err in collecting from many areas, but from too few Within each survey there can be a mixture of substrates substrate tree species. (bark, litter), the pH distribution should approximate a In general, there is an excellent consistency between all normal curve, and if the survey is over a large distance it surveys and the four types of litter, with most of the species will only be useful if there is little change in the mean pH with listed in Table 1 being part of an angiosperm litter species distance. All large surveys were considered for inclusion in association. Species that are part of this species association this analysis but many could not be used because the pH values generally occur reasonably randomly across the table, and their were not reported in a useful form (pH range is not useable). abundance is reasonably consistent. This angiosperm litter The surveys used in this analysis are as follows. species association incorporates the previously published 1. A survey of myxomycetes found on bark on several assessments for liana stems (Wrigley de Basanta et al. traverses across Australia (Wellman 2019). This survey 2008), and twigs (Cedeño et al. 2014). Hence it seems is of much wider extent than other surveys, consequently likely that there is only one myxomycete species the mean pH of sections of the traverses changes along the association on angiosperm forest tree litter – that defined by traverses. This effect has been corrected by adjusting the Table 1. Complementing this is the conclusion of Wellman pH within some parts of the traverses. Records in the (2017) that for temperate angiosperm forests the myxomycete Tropical Species Association have been adjusted by 1.0 species associations on dead wood were similar for similar pH units, and records in the Tropical/Northern Arid Species climate areas – for Australia, New Zealand, Patagonia, Britain Association transition have been adjusted by 0.54 pH units. and Spain. 2. A survey in the winter cold desert of western Kazakhstan There is an apparent inconsistency between the conclusion (Schnittler 2001). that worldwide the angiosperm closed-forest litter types have a 3. A survey in the arid climate Volga River Basin in Russia single species association, and the conclusion of Walker (Novozhilov et al. 2006). The reported mode pH of each (2016) that the litter types within one myxo survey have species was used, not a mean. different species assemblages. Walker cultivated 288 4. A survey in the monsoon lowland tropical rainforest in samples of both leaf litter and small woody debris. The 10 southern Vietnam (Novozhilov et al. 2017a). most abundant species for each substrate had six species in 5. A survey in the temperate deciduous forest in Germany common between the substrates, and four species each not in (Schnittler et al. 2006). common between the substrates, so she concluded that there 6. A survey in the tropical forests in eastern Mexico (Lado was a difference in species between the two substrates. et al. 2003). However almost all these 15 selected species are members 7. A survey of liana stems from tropical rain forests in a variety of the litter species association of Table 1,sotheyarefoundin of countries (Wrigley de Basanta et al. 2008). The mean pH of both leaf litter and woody debris worldwide. Everywhere the all liana substrates was similar in the various areas. separation of species into substrate type is likely to be 8. A survey in the tropical forests of Christmas Island in the influenced by the local pH and substrate physical effects north-east Indian Ocean (Stephenson and Stephenson 2019). discussed later in the paper. The analysis does not use substrates where the description This conflict can be summarised as follows. It is generally mentions palms, Pandanus, or seed pods as these have very accepted that in a survey the different substrates give different different pH from the pH range of other substrates. species assemblages. Presumably one can get a better mean of 9. and 10. Surveys in Twin Creeks and Baskin localities within the substrate’s species association by adding the species the southern Appalachian Mountains, USA (Stephenson occurrences in many surveys. However, when we do this SL, unpubl. data). the mean assemblages of the various substrates are the 11. A survey in Norfolk Island, in the western Pacific Ocean same within experimental error. Something is wrong. The between New Zealand and New Caledonia (Stephenson and error is thought to be in assuming that for surveys in two Stephenson 2020). places, with different trees, there is the same division of species between substrates. Surveys 2–7 were analysed using information within each published paper, whereas surveys 1 and 8–11 were analysed using unpublished spreadsheets of the survey records. The Myxomycete species and substrate acidity surveys range from large to small in number of samples and For a long time it has been known that substrate acidity (pH) is area, and range from rain-forests within the tropics to mid- an important control on which myxomycete species is present latitude, wet forests and arid regions at mid latitudes where in moist culture studies (e.g. Härkönen 1977). However, the the dominant plant is grass or scrub. The surveys used one or details of the pH effect have not been studied. This is in part more of a wide range of substrate types. A paper by Lado et al. because the form of the relationship has not been known, and (2011) with mainly cacti and succulent substrates was not used in in part because previously there was not enough survey this study because of suspected change in the mean substrate pH information available to form the basis for a pH study. To over the survey, due to both the large range in altitude of the study the effect of pH we need a range of surveys, large and substrates, and to some collections being from internal drainage small, from wet to arid climate, the surveys having at least areas with alkaline soils. 34 Australian Journal of Botany P. Wellman

The surveys were analysed as follows. A spreadsheet was Table 2 shows that the survey pH values standard deviation made with one column giving the myxomycete species, and (s.d.) is relatively large in surveys 1 and 5 (s.d. 0.86, 0.84) and two columns for each survey. The two columns give, for each is relatively small in survey 10 (s.d. 0.51), but there is no species found in that survey with more than 6 records, the change in the spread of species pH6.0 values between Arcyria number of records and the mean pH of the record’s substrate. cinerea and Perichaena vermicularis. Hence Table 2 is Only species which have a mean pH available for two or more consistent with species pH6.0 being constant within surveys are listed in this table. The eleven surveys had a mean sampling error with varying standard deviation in survey pH of all records varying from 5.2 to 7.7. First, for each survey pH values. a constant (survey pH6.0) was added to the species’ mean pH Table 3 is a longer species list that includes species with a values to adjust the mean survey pH value to 6.0. Then a mean less accurate species pH6.0 estimate. This list has been derived pH for each species was calculated (species pH6.0). These from a spreadsheet of the 11 surveys with all species with five preliminary estimates of survey pH6.0 and species pH6.0 were or more records and their pH6.0 values. The species mean pH6.0 then adjusted alternately to minimise the residuals. values listed are of four accuracies; the most accurate values Table 2 gives the final model: survey pH6.0 corrections, the are derived from two or more surveys each with 6 or more species pH6.0 values, and the residuals of the model. The records (Table 2), less accurate values are from one survey residuals on the spreadsheet have a standard deviation of with 10 or more records, still less accurate values from one 0.2 pH unit. The strength of the above analysis depends survey with 6 or more records, and the least accurate from one greatly on a few species that are relatively common. survey with only 5 records. The species pH6.0 values are most Species that were observed on four or five surveys are accurate if there is more than one survey used in the Arcyria cinerea, Echinostelium minutum, Macbridela calculation. If there is only one survey used then the oblonga, Perichaena corticalis, Perichaena depressa, accuracy decreases fast with fewer records, by 1/Hn, where Perichaena vermicularis,andStemonitis fusca. n in the number of pH records. In order to understand the

Table 2. A model of acidity variations in myxomycete surveys Along the left is a list of myxomycete species and their preferred average pH standardised to a mean of pH = 6.0. Along the top is a list of myxomycetes surveys. The numbers in the body of the table are residuals from the model in the text in pH units. The surveys referred to are: 1, Wellman (2019); 2, Schnittler (2001); 3, Novozhilov et al.(2006); 4, Novozhilov et al.(2017a); 5, Schnittler and Tesmer (2008); 6, Lado et al.(2003); 7, Wrigley de Basanta et al.(2008); 8, Stephenson and Stephenson (2019); 9, Stephenson, unpubl. data, Twin Creeks survey; 10, Stephenson, unpubl. data, Baskins survey; 11, Stephenson and Stephenson (2020); 12, Stephenson, unpubl. data, Gaudineer survey

Area Aust Kazak Volga Viet Germ Mexi Liana Chris Twin Bask Norf Survey number 1 2 3 4 5 6 7 8 9 10 11 Survey mean pH 5.23 7.71 6.6 6 5.8 6.6 6.85 6.11 5.71 5.23 6.89 Survey pH s.d. 0.86 0.55 0.8 0.47 0.59 0.73 0.71 0.51 0.47 pH6.0 correction 0.58 –1.45 –0.37 0.28 0.08 –0.42 –0.91 0.07 0.47 0.73 –0.86 Substrate types b b,l all l t lf all all b,t,l b,t,l all

pH6.0

Arcyria cinerea 5.96 0.3 –0.4 0.2 –0.1 0 –0.1 0.3 –0.2 0 0.1 Arcyria pomiformis 5.07 –0.1 0.2 0 Collaria arcyrionema 6.15 0.1 –0.1 Comatricha laxa 5.26 0.2 –0.2 Cribraria violacea 6.67 0.1 –0.1 0 leucopodia 6.07 0.5 –0.5 Diderma effusum 6.27 0.3 0.3 Diderma hemisphaericum 5.91 –0.1 0.1 Didymium difforme 6.34 0 0 Didymium iridis 6.04 0.1 0.1 Didymium squamulosum 6.42 0.1 0.2 –0.3 Echinostelium colliculosum 6.34 –0.2 0.2 Echinostelium minutum 5.41 –0.2 0.1 0.1 Lamproderma scintillans 6.45 –0.1 –0.1 0.1 Licea kleistobolus 6.13 –0.3 0.3 oblonga 6.28 –0.1 0.2 Perichaena chrysosperma 6.27 –0.1 0 0.2 –0.1 Perichaena corticalis 6.36 0.1 0 –0.1 0 Perichaena depressa 6.29 –0.2 –0.2 0.1 0 0.3 Perichaena liceoides 6.15 0.1 –0.1 Perichaena vermicularis 6.36 0.2 –0.3 0 0.2 0 0 Physarum compressum 6.38 –0.1 –0.2 0.3 Physarum decipiens 6.23 –0.2 0 Physarum leucophaeum 6.3 0 0 Physarum notabile 6.09 0.3 0.2 –0.4 Stemonitis fusca 5.96 0.2 –0.1 0 –0.1 0 Controls on myxomycete species and assemblages Australian Journal of Botany 35

significance of the species pH6.0 values the species have been Table 3. Relative acidity preferences of myxomycete species listed in the systematic order of Leontyev et al.(2019), using The pH values listed are of four accuracies, with the most accurate (***), and subclass, order and family. the less accurate (**), (*), and no asterisk. The classification of the species is From the published literature one would anticipate that summarised on the left, where the subclasses are: Lucisporomycetidae and species having lime in the fruiting body (most of the Order Columellomycetidae, the orders are: Cribrariales, , , Echinosteliales, Clastodermatales, , , and Physarales) would prefer more alkaline environments than the Families are: Dianemataceae, Trichiaceae, , species without lime in the fruiting body. However what is Amaurochaetaceae, Lamprodermataceae, and found in Table 3 is a different pattern. Species with lime in the Subclass Order Family Species pH6.0 fruiting body have a pH6.0 that is slightly below 6.0 (Badhamia)orabove6.0(Didymium, Physarum), and Luc Cri Cribraria confusa 5.3** species without lime in the fruiting body also have a Luc Cri Cribraria microcarpa 5.4** preferred pH both above and below 6.0. The grouping of Luc Cri Cribraria minutissima 4.9** 6.0 Luc Cri Cribraria violacea 6.7*** similar pH6.0 seems to be more a characteristic of genera, with Luc Lic Licea belmontiana 6.3** many genera having a narrow range in pH6.0;withPerichaena Luc Lic Licea biforis 6.2** having values of 6.2–6.8, Didymium 6.0–6.4, Badhamia Luc Lic Licea denudescens 6.5** 5.2–5.9, Physarum 6.1–7.1 and Comatricha 5.1–5.3. Genera Luc Lic Licea kleistobolus 6.1** Luc Lic Licea operculata 5.7** listed with a reasonable number of species but with a greater Luc Lic Licea pygmaea 5.9* range of pH6.0 above and below 6.0 are Cribraria, Licea and Luc Tri Dia Calomyxa metallica 6.0** Luc Tri Tri Arcyria cinerea 6.0*** Arcyria. It seems unlikely that the species pH6.0 numbers in fi Luc Tri Tri Arcyria incarnata 5.6** Table 3 are random, and the model that best ts the Luc Tri Tri Arcyria margino-undulata 6.0* information is that species in the same tend to have a Luc Tri Tri Arcyria pomiformis 5.1*** similar pH6.0 value. This is likely to be because of inheritance; Luc Tri Tri Perichaena corticalis 6.4*** that is because they have inherited the same gene. Luc Tri Tri Perichaena depressa 6.3*** Luc Tri Tri Perichaena dictyonema 6.8** The major control on the mean survey pH of Table 2 is not Luc Tri Tri Perichaena liceoides 6.2** clear. It could in part be soil pH, because the two highly alkaline Luc Tri Tri Perichaena vermicularis 6.4*** mean surveys pH are in cold deserts (surveys 2 and 3 of Col Ech Echinostelium arboreum 6.4** Table 2). However the other values of mean survey pH show Col Ech Echinostelium colliculosum 6.3*** Col Ech Echinostelium minutum 5.4*** little correlation with the map of alkaline and acid soils derived Col Cla Clastoderma debaryanum 6.7** from soil aridity (Slessarev et al. 2016; Wikimedia 2020). Col Stem Stem Macbrideola decapillata 6.7* Col Stem Stem Macbrideola oblonga 6.3*** Col Stem Stem Stemonitis foliicola 5.3* A budget of pH variance Col Stem Stem Stemonitis fusca 6.0*** Col Stem Stem Stemonitis pallida 4.7* Another method of expressing the control of substrate pH on Col Stem Ama Comatricha elegans 5.1** the distribution of myxomycetes is to subdivide the pH effects Col Stem Ama Comatricha ellae 5.3** into a pH budget - that is quantifying the various pH effects. Col Stem Ama Comatricha laxa 5.3*** Col Stem Ama Comatricha pulchella 5.5*** The estimates of the effects have been derived from data given Col Stem Ama papillatum 5.1** in published papers, and spreadsheets of records as follows. Col Stem Ama Paradiacheopsis fimbriata 4.9** The pH mean scatter of one substrate at one site has been Col Phy Lam Collaria arcyrionema 6.2*** calculated using the pH measurements in three Petri dishes Col Phy Lam Lamproderma scintillans 6.5*** Col Phy Did Diderma effusum 6.3*** from the triplicate site samples in Stephenson and Stephenson Col Phy Did Diderma hemisphaericum 6.1*** (2019) (and also in Baskins survey and Gaudineer survey, Col Phy Did Didymium anellus 6.0** Stephenson SL, unpubl. data) using species record Col Phy Did Didymium difforme 6.3*** spreadsheets. This gives a s.d. of generally 0.2–0.35 pH units, Col Phy Did Didymium dubium 6.0** Col Phy Did Didymium iridis 6.0*** where the lower values are probably in cases where collected Col Phy Did Didymium nigrips 6.3 substrate material is from few tree species, and higher values Col Phy Did Didymium squamulosum 6.4*** frommanytree species.Within a surveythevariationofpHwithin Col Phy Phy Badhamia foliicola 5.2** Col Phy Phy Badhamia macrocarpa 5.7** one species has (for surveys 1 and 8 using spreadsheets) a mean Col Phy Phy Badhamia utricularis 5.9** s.d. of 0.60 pH units. The differences between the mean pH6.0 Col Phy Phy Badhamiopsis ainoae 5.9** of the myxomycete species is calculated from Table 2 as a s.d. Col Phy Phy Craterium concinnum 5.5* of 0.37 pH units. The effects of physical (and other chemical) Col Phy Phy Physarum cinereum 6.2** Col Phy Phy Physarum compressum 6.3*** factors of the substrate is given by the residuals of the mean pH in Col Phy Phy Physarum cratoriforme 7.1** the model of Table 2, with a s.d. of 0.20 pH units. The total Col Phy Phy Physarum decipiens 6.2*** variation in pH measurements within a large survey is between Col Phy Phy Physarum didermoides 6.4** 0.5 to 0.8 pH units (surveys 1, 8, 10–12 using spreadsheets). The Col Phy Phy Physarum lakhanpalii 6.8 Col Phy Phy Physarum leucophaeum 6.3*** variation in mean pH of surveys (from Table 2) has a s.d. of Col Phy Phy Physarum melleum 6.1* 0.76 pH units, but the true World value is likely to be higher as Col Phy Phy Physarum notabile 6.1** not all localities and substrates in the World were sampled. Col Phy Phy Physarum oblatum 6.1* Table 4 lists the pH budget. The effects are also expressed Col Phy Phy Physarum pusillum 6.3* Col Phy ~ 6.1*** as variances, because the variances can be added to get the 36 Australian Journal of Botany P. Wellman combined effect. The variance is the square of the s.d. Within a Table 4. An acidity budget for a ‘normal’ myxomycete survey survey the total variance calculated from the components Estimates of the pH variation due to various causes in field surveys approximately equals the total variance calculated directly pH Variation – type pH Units from all the survey pH values treated as one population. s.d. Variance Within a survey, the main variance is from the pH variation – within a species. The control on the species is only understood One substrate at a site, between Petri dishes 0.25 if there are sufficiently records for each species such that the Within a survey mean pH can be better defined. A species pH measurements Within a species 0.60 0.37 have a s.d. of 0.60, so if there are six records for a species then Between species mean pH6.0 0.37 0.13 the species pH mean value has a s.d. of 0.60/H6=0.25.Then, Residuals from model 0.20 0.04 Total within a survey – calculated – 0.54 considering the species means (not measured values), the – differences between the species mean pH (with a s.d. of Total variation within a survey observed 0.80 0.65 ~0.37) are the dominant control on the pH pattern observed. Variation in the mean pH of surveys, Worldwide 0.76 0.58 World pH variance – calculated – 1.23 Not all myxomycete surveys will give results consistent with the above budget. (1) The surveys selected must have pH values with a reasonable having the highest rank. As the data is noisy the myxomycetes spread (over 2 pH units). If substrates of only a few tree species that have the same number of tree genera as substrate genera are sampled then the preferred mean pH of the have had their data averaged, so lines are shown for the myxomycetes species will be constrained to be less than average relationship for 3, 4, 5, 8, 9 and 12 tree genera, the spread of the tree’s pH. with the number of myxomycete species data averaged (2) In many surveys the distribution of substrate pH is a being 5, 6, 4, 4, 2 and 3 respectively. When allowance is broad single peak, approximating a normal distribution. made for experimental error, the lines are approximately Substrates forming a secondary peak in the pH distribution straight and parallel, with mean slope of ~1.1. Importantly, (such as palms or Pandanus) have to be excluded from an there is no evidence for the lines having a change in slope part analysis if you are going to assume a normal distribution. way across the figure. This is consistent with a single power (3) The mean pH of the survey cannot vary significantly law relationship between the number of records of a host tree across the survey, or must be corrected for. In this genus and the rank of this number. In particular, there is no respect the Australian survey used in this analysis has obvious surplus or deficit of tree genera with single records. not really been adequately adjusted to one mean pH value, Hence, the data are consistent for each myxomycete species, but the adjustment was the best available with sample with the number of records for each host being determined by spacing of 30–50 km across a continent. one sampling relationship – a random sampling of substrates In particular there is no evidence for myxomycetes growing Substrate frequency against rank poorly on less common substrates. Although Fig. 1 is Information about myxomycete species apparent substrate consistent with a single model of abundance against rank, it preference can be summarised in tables showing a list of does not prove that there is a single straight-line relationship. myxomycetes species, and for each species a list of the A model with two straight lines of slightly different slope substrate tree genera and the number of records for each needs a very large amount of data to be evident, and for each host genus ordered by rank. The potential information can myxomycete species we only have a little data. Table 2 is be divided into the numeric information of such a table (the consistent with there being a lot of chance in where shape of the relationship of substrate frequency against rank myxomycete fruit are found. ignoring the tree names), and the tree name information with or The sampling of the bark samples is really not random, in without substrate physical properties. This section discusses that the sampled substrates do not have an equal chance of the numeric information. This numeric information can be being selected. Some substrates are preferentially sampled derived from the results of any myxomycete survey, the because they give many myxomycete species or are common; important question is whether the information is other substrates are rarely sampled because they are marginally informative, or only reflects random processes. suitable or uncommon. The statistical relationship of Fig. 1 A common myxomycete species always occurs most seems to be robust even with non-random sampling. commonly on several tree species substrates and less A possible difference between common and less-common commonly on many other substrates. What is given here is substrates can be investigated another way. If we take the data a model quantifying the effect of chance on substrate selection. for 57 sites of Arcyria cinerea in the Wellman (2019) record The data used here is from a uniform, large dataset: the raw list then the most common substrate for Arcyria cinerea is on data used to prepare table 2 in Wellman (2019)for Eucalyptus of ‘coolabah’ type bark (37% of sites). Eucalyptus myxomycetes on bark collected from trees growing across with stringy bark and Corymbia are next most common, and Australia. Plotted on the y-axis of Fig. 1 is the log of the the remainder of the less common substrates with 3, 2 and 1 number of records of a tree genus substrate, and plotted on the sites per tree genera form 37% of the sites. When the most x-axis is the log of the rank of the tree genus. Tree genera are common substrate is compared with the less common ranked with the genus with the maximum number of records substrates they have the same average number of fruiting having a rank of one, and the genera with only one record bodies (21), and nearly the same average ratio of Controls on myxomycete species and assemblages Australian Journal of Botany 37

1.4 if we can obtain numerous large surveys with the critical physical properties of the substrates. Unfortunately, this information is not available at present. However, some of 1.2 the issues are discussed below by looking at a single survey, with the substrate tree names and a limited amount of information about the physical properties of the substrate. 1.0 The dataset used is again the Wellman (2019) survey of myxomycetes on bark in Australia. The samples are from a very large area of arid land and the dryer parts of the non-arid 0.8 areas. Only thick, old and weathered bark was sampled. For this survey the collected substrates fall into three major groups: 1. Acacia has hard and massive bark. 2. The eucalypts

ber of records of a tree genus) 0.6 (Eucalyptus, Corymbia and Angophora) have variable bark but those collected were mainly soft, but with some of medium 10 density. 3. The numerous remaining tree species mainly had Log (Num medium density and medium porosity bark, but a few are hard 0.4 or soft. There are 298 records of Acacia, 544 records of eucalypts, and 512 records of other tree species. Table 5 (from table 2 of Wellman 2019) gives a list of 0.2 myxomycete species, and for each species the total number of records, and the substrate tree genera listed in order of the number of records. One tree genus, Eucalyptus, has been 0 subdivided into 4 bark types. This procedure is very useful 0.0 0.5 1.0 for future Australian surveys, as it directly relates myxomycete Log (Rank of number of records) 10 species to known Australian trees. However to people on other continents it gives no quantitative information on bark Fig. 1. Selection by myxomycete species of a tree species substrate. Plot properties, and because the number of samples in the various of log (the number of records of the tree species) against the log (rank 10 10 genera or species groups is very uneven, the inferred of the tree species). Each line is the average for several myxomycete species. The lines show the average relationship for myxomycete species myxomycete species groups of Table 5 are dominated by having substrates with maximum ranks of 3, 4, 5, 8, 9 and 12. the common genera, hence any information analysis is biased. However, there is a way to use subjective information on the myxomycetes’ preference for substrates of different ‘A. cinerea fruit volume /total sample myxomycete fruit hardness. The relative hardness of the various barks has volume’ of 0.27 compared with 0.25. Hence this small been subjectively estimated during a survey: in collecting sample is consistent with A. cinerea being equally the bark samples, in the cutting of the bark slivers for the productive on the substrate of trees on which it is common, Petri dishes, in the cutting out of myxomycete fruit, and as those on which it is rarely found. through poking the bark by a sharp spike after cultivation. A related question is whether a tree that is exotic to the area Note that most of these procedures indicate the hardness of dry can get suitable myxomycete spores from elsewhere and have bark. If the barks genera/species can be divided into hard, normal myxomycete productivity. Wellman (2019) mentioned medium and soft, then we get a measure of the myxo species that very isolated exotic trees in the arid inland of Australia preference for the types of bark. This is given in the last had small myxomycete productivity. Samples of seven isolated column of Table 5 as a three-figure number. For Calomyxa trees exotic to the area gave (for five Petri dishes) a spore metallica the number 541 means that 50% of the records were harvest with a mean of 1.8 mm3, and number of species with a hard, 40% were medium and 10% were soft. The three digits mean of 3.4 species. This is much smaller than the mean give both a measure of the mean hardness observed in the harvest for arid Australia: a spore harvest of ~5 mm3,and records, and the observed spread in the hardness values. In number of species of 6. However the number of exotic trees theory, these proportions should be corrected to allow for the sampled is small, so the lower productivity may be due to different numbers of hard, medium and soft substrates; chance. A confirmation of this lower productivity of however, the number of records for the various degrees of myxomycetes on locally exotic trees in arid areas is hardness was similar (hard 413 records, medium 503 records required. The colonisation of isolated exotic trees is in part and soft 403 records), so no correction was made. In addressed by the habitat colonisation model of Schnittler and Table 5 these proportions have been used to subdivide the Tesmer (2008), looking at the ‘island’ effect on myxomycete species into three groups based on whether the maximum species numbers. number of records was in the hard, medium, or easy group. The two problems with the hardness reported in Table 5,isthat the hardness used is subjective, and the mode hardness used Physical properties of substrates has low reliability for those species with few records. Any The dominant myxomycete species growth requirements in future use of hardness should be quantitative, and use wet bark. terms of physical properties of the substrate can be determined Table 5 gives for the myxo species average hardness (peak of 38 Australian Journal of Botany P. Wellman

Table 5. The substrate of myxomycete species From Wellman (2019). Columns give the species of myxomycetes, the substrate group, the number of species records (n), and the most common tree substrates. Tree genera are: Ac, Acacia;Ata,Atalaya;Bra,Brachychiton;Bur,Bursaria; Cal, Callitris;Cas,Casuarina; Cor, Corymbia;Eb,Eucalyptus ‘coolabah’ type; Ere, Eremophila; Ery, Erythrophleum;Ef,Eucalyptus fibrous bark; Ei, Eucalyptus ‘iron bark’ type; Em, Eucalyptus with fissured bark; Gei, Geijera;Gre,Grevillia; Hak, Hakea; Lys, Lysiphyllum; Myo, Myoporum; Owe, Owenia;San,Santalum;Sch,Schinus. Hardness is expressed as a three-figure number, where the number 541 means that 50% of the records were hard, 40% were medium and 10% were soft. Arcyria sp. H is described as Arcyria sp. in Davison et al.(2008)

n Tree genera, number of trees Hardness pH6.0 HMS Peak Arcyria pomiformis 9 Ery2, Hak2, Cal2 432 H 5.1 Badhamiopsis ainoae 36 Ac20, Cal4, Cas4, Ata2 730 H 5.9 Calomyxa metallica 51 Ac18, Eb7, Cal6, Cas3, Bra2, Ei2 541 H – Clastoderma pachypus 11 Ac3, Gre3 442 H – Didymium dubium 64 Ac24, Eb15, San4, Cas3, Gre3 442 H 6.0 Echinostelium minutum 16 Aca3, Cor2 433 H 5.4 Licea biforis 54 Ac21, Cas6, Eb5, Ef3, Gre3, Lys3 541 H 6.2 Licea kleistobolus 117 Ac34, Eb7, Ef5, Hak5, Cal5, Lys3 433 H 6.1 Licea operculata 45 Ac20, Gre4, Cas3, Ery3, Hak3 640 H 5.7 Licea scyphoides 22 Ac14, San2 640 H – Macbrideola oblonga 65 Ac19, Eb11, Cal7, Cas3, San3 442 H 6.3 Physarum decipiens 90 Ac33, Eb17, Cas6, Cal3, Gre3 442 H 6.2 Physarum leucophaeum 54 Ac16, Eb11, Cal2, Gei2, Lys2 442 H 6.3 Badhamia macrocarpa 11 Ac3, Bur2, Cas2 172 M 5.7 Badhamia versicolor 11 Ac3, Ere2 271 M – Comatricha ellae 109 Ac24, Eb20, Gre10, Hak10, Cal6 343 M 5.3 Comatricha laxa 22 Eb3, Hak3, Ac2, Ei2, Gre2 262 M 5.3 Enerthenema papillatum 50 Eb10, Cor7, Ef5, Gre4, Hak4 154 M 5.1 Licea pygmaea 20 Ac5, Eb5, Cas2 343 M 5.9 Paradiacheopsis fimbriata 32 Cor6, Gre5, Hak5, Ei3, Ac2, Cal2 172 M 4.9 Physarum cratoriforme 36 Eb10, Ac6, Cal5, San4 343 M 7.1 Stemonitis fusca 14 Eb6, Cas4 451 M 6.0 Stemonitis mussooriensis 7 Ery2 433 M – Trichia contorta 16 Eb5, Ac4, 343 M – Arcyria cinerea 70 Eb 27, Cor7, Ef6, Ei3, Cal2, Bra2 136 S 6.0 Arcyria sp. H 20 Eb6, Cor4, Ef2, Ei2, 5 055 S 5.1 Clastoderma debaryanum 9 Eb5 136 S 6.7 Comatricha elegans 76 Cor18, Eb11, Gre7, Ef7, Ac5 145 S 5.1 Comatricha pulchella 6 Eb3 226 S 5.5 Comatricha vineatilis 4 Cor4 10 S – Cribraria bicolor 3 Eb2 037 S – Cribraria confusa 20 Ef6, Cor4, Ery4 226 S 5.3 Cribraria minutissima 35 Cor8, Ef7, Eb2, Gre2 235 S 4.9 Cribraria violacea 23 Eb13, Ei2 136 S 6.7 Dianema corticatum 12 Eb7, Ac3 424 S – Echinostelium arboreum 15 Eb7 145 S 6.4 Macbrideola decapillata 8 Eb4, Lys2 415 S 6.7 Perichaena corticalis 11 Eb6 136 S 6.4 Perichaena vermicularis 53 Eb24, Bra2, Ac2, Gei2 136 S 6.4

the subjective hardness) and the pH6.0 value. Importantly there length of time after rain that the myxomycetes can eat before seems to be no correlation between the hardness values and the the water evaporates and they transform to a resting phase. pH values. This is consistent with myxomycete species (or Fortunately, water holding capacity is relatively easily groups of species) having distinct ecological niches, differing measured by weighing a substrate before and after soaking. in both preferred pH6.0 and in preferred hardness. Hardness or density are both techniques difficult to measure It is quite possible that, other than pH, the substrate accurately for normal samples, particularly twigs and leaves. property that is most important to myxomycete growth is They are not good measures of suitability for myxomycete water holding capacity. There are two reasons for this: feeding because they are a measure of the proportion of air water holding capacity is a measure of the proportion of the in a dry sample, not the proportion of the substrate that is internal substrate that is accessible by interconnecting voids accessible. It seems likely that there will be no major progress which controls its access to food, and it is a measure of the in further defining myxomycete species microhabitat until Controls on myxomycete species and assemblages Australian Journal of Botany 39 future major surveys are carried out with both chemical (pH) surveys, with a greater mass of bark material, whereas the and physical properties (water holding capacity) of the surface area cultivated is very similar. Most pieces of bark substrates. have a thin, weak, grey outer layer, and a stronger darker inner Two myxomycete species where substrate choice, other part. It seems likely that the inner part of the bark samples is than pH, is more, or less, important can be identified by having not sufficiently decomposed for bacteria, and that the raw pH values with a high standard deviation about their mean similarity in productivity of the two materials is due to the of 0.7 to 1.0 pH units. Acyria cinerea prefers the softer barks of similar surface area of the cultivated material. Eucalyptus of the ‘coolabah’ type or Corymbia, even though While the two histograms of Fig. 2 have a similar shape, the neither of these substrates has a relative pH close to what it origin of the highest volumes is different. Wellman (2019) prefers elsewhere in the World. For A. cinerea soft bark is so showed for the bark survey the samples with the highest important that in the driest part of Australia where there are no productivity have an abnormally big difference between the soft barks the species does not occur on bark. Licea total spore volumes of the species with the highest volume and kleistobolus in unusual in having no particular preference of the next highest volume. This is thought to be due to carry over substrate. of mass between feeding events, leading to a large ‘swarm’ event giving the highest volume. In contrast, in the liana Myxomycete total spore productivity of different substrates survey the samples with the highest productivity have a A measure of the myxomycete productivity in the New South normal difference between the total spore volumes of the Wales liana survey is the total spore volume harvested for the species with the highest volume and the next highest five Petri dishes of each sample. The average volume of the volume, so their harvest is thought to be due solely to the fruiting body of each species has been estimated, mainly using last growing event. fruiting body dimensions of Poulain et al.(2011). The harvest for each sample is calculated by multiplying the number of Change in mean substrate acidity with latitude fruiting bodies by this fruiting body volume, and the summing the volumes for all the species in the sample. Fig. 2b gives a Myxomycete (and fungal) species assemblages would be histogram of the logarithms of these volumes. The curve is affected by systematic differences in mean acidity (pH) of rather noisy because of the small number of samples. The the decayed plant material substrates, either a difference in the majority of the volumes form a histogram peak with a high mean acidity of different substrates at one latitude, or a ~9 mm3, with a rather fat tail to 47 mm3, and a very long tail to systematic variation of acidity with latitude. To study this small volumes. The curve is consistent with most samples there are a large number of measurements of acidity reported giving a harvest forming a broad peak with a mode at about a by myxomycete researchers, and measurements of timber 0.9 mm3, with about one-quarter of the samples giving low pH. Table 6 lists the acidity measurements relevant to the harvests due, it is thought, to the stems being unsuitable for present paper, both from previous publications and some bacterial growth. The histogram is very similar to that of bark new measurements. Within a myxomycete survey the pH samples from Western Australia (Wellman 2019) shown in measurements generally have good internal consistency, – Fig. 2a. As the shape of the curves are similar, it is likely that with a standard deviation of 0.4 0.6 pH units. The latitude attributed to the pH mean is the mean of the samples latitudes similar processes are controlling myxomycete productivity on  liana twigs and dead bark on a living tree. The average mass of and 10 for tropical samples. A set of measurements in Finland plant material in the Petri dishes differs between the two (Härkönen 1977) was not used because of possible effects of acid rain. The accuracy of the mean pH values in Table 6 depends on both the number of measurements made 40 (a) (‘N’ in Table 6) and the standard deviation of the samples, and on the form of the real population – in part whether the samples 20 are a random sample of the real acidity population, and in part whether some samples are less or more decayed. Fig. 3 shows the data from all decayed substrates plotted 0 together. Different substrates have different symbols. There is

Number of samples -1.0 0.0 1.0 1.8 considerable scatter in the mean values derived from single surveys but the scatter of mean values forms a pattern. In the 8 (b) relation of mean pH with latitude there appear to be no systematic differences between the decayed substrate types 4 (aerial liana, aerial twigs, bark, ground twigs, ground leaf litter, or ground logs). In this figure the average pH for all decayed substrates is 6.5 at tropical latitudes (23N–23S), and 0  Â Number of samples -1.0 0.0 1.0 1.8 is 5.6 at ~35 latitude (6.52, with 2 sdm = 0.18; 5.59, 2 Â sdm = 0.29; sdm being standard deviation of the mean). Log volume of spores (mm 3 ) 10 3 The form of the mean variation of pH with latitude is not 0.1 mm3 1 mm 10 mm3 defined by the data points, but the model shown as a dotted line Fig. 2. Histogram of myxomycete harvest volume. (a) Bark substrate, on the figure is possible - a constant value of 6.5 in the tropics, from Wellman (2019). (b) Liana twigs substrate. with a linear decrease with higher latitude. The measured pH 40 Australian Journal of Botany P. Wellman

Table 6. Acidity of myxomycete substrates and timber Data origin: 1, Novozhilov et al.(2017a); 2, Stephenson and Stephenson (2019); 3, Stephenson et al.(2008); 4, Wrigley de Basanta et al.(2010); 5, Cedeño et al. (2014); 6, Wrigley de Basantaet al.(2008);7, Black et al.(2004); 8, Rosinget al.(2007); Wellman(2019); 9, SchnittlerandStevenson(2000); 10, Walker(2016); 11, Stephenson and Stephenson (2020); 13, Massingill and Stephenson (2013); 14, Lado et al.(2003); 15, Bootle (1983); 16, Tetréault (1999); 17, this paper

Location Mean pH s.d. or range n Latitude Reference Decayed substrate Liana stem Peru 6.7 0.4 31 3.5S6 Australia, Cairns, sky crane 6.4 0.5 27 16S6 Australia, Cairns, near ground 6.5 0.6 19 17S6 Puerto Rico 7.2 0.6 68 18N6 Mexico 6.7 0.4 27 19.5N6 Australia, NSW, ACT 6.2 0.5 17 33S17 Aerial twigs Christmas Island 6.7 0.9 7 10.5S2 Vietnam 6.3 – 217 11N1 Australia, Queensland 6.5 6.3–6.8 8 16.5S7 Australia, ACT 5.8 0.7 13 35S17 Argentina, Patagonia 5.0 0.6 4 46S4 Ground twigs Panama 6.2 500 9N10 Christmas Island 6.4 0.4 8 10.5S2 Costa Rica 6.7 4.3–8.1 70 10N3 Norfolk Island 5.9 0.5 9 29S11 Australia, NSW 5.4 5.1–5.5 14 36S3 USA, all 5.4 3.7–8.1 91 37N3 USA, Virginia 4.9 ?60 37N5 New Zealand 5.1 4.6–5.3 16 45S3 Argentina 5.1 5.0–5.2 5 54S3 Bark Christmas Island 7.5 1.1 13 10.5S2 Costa Rica 6.6 0.5 126 10.5N9 Costa Rica, cloud forest 6.4 0.9 54 10.5N9 Vietnam 6.3 296 11N1 Mexico 7.0 0.9 62 21N21 Norfolk Island 5.0 1.1 13 29S11 Australia, Victoria & NSW 4.8 1.16 40 35S8 USA, Arkansas 6.7 0.6 7 36N13 Argentina, Patagonia 5.1 0.5 4 46S4 Ground leaves Panama 6.4 500 9N10 Christmas Island 6.6 0.6 8 10.5S2 Costa Rica 6.4 0.7 198 10.5N9 Costa Rica, cloud forest 5.9 0.8 119 10.5N9 Vietnam 6.0 – 382 11N1 Australia, Qld 6.6 6.3–7.3 11 16.5S7 Mexico 6.6 0.5 92 21N14 Norfolk Island 6.5 0.6 12 29S11 USA, Virginia 5.2 3.6–6.5 60 37N5 Argentina, Patagonia 4.8 0.5 4 46S4 Wood Vietnam 5.5 – 58 11N1 Mexico 6.7 1.1 71 21N14 Australia, ACT 5.2 0.5 13 35S17 USA, Arkansas 6.0 0.7 5 36N13 Undecayed timber or wood Tropical timber 5.0 0.6 17 23N–23S16 N. Hemisphere 5.1 0.9 27 41N16 N. Hemisphere 5.0 0.4 5 55N16 Australia, ACT, local 4.9 0.7 8 35S17 Australia, ACT, exotic 5.1 0.7 12 35S17 Tropical timber 4.7 0.4 11 10 15 Australia, not Eucalyptus 4.6 0.7 17 28S15 Australia, Eucalyptus 3.7 0.4 14 34S15 Controls on myxomycete species and assemblages Australian Journal of Botany 41 values have a variance about their mean of 0.49, and a variance Australia (in the southern hemisphere) are reported by about the model line on Fig. 3 of 0.24, so the model line Bootle (1983) and measurements for the northern explains about one-half the scatter of the observed pH hemisphere collated by Tetréault (1999). These reports measurements. show that the pH of most sampled trees is in the range of 3 It is interesting that the bark substrate gives a similar pH to to 7. Lachowicz et al.(2019) shows that the variation in pH the other substrates. Bark samples in Australia collected for within and between adjacent forest stands of one species is less myxomycete substrates are of two types. For a minority of than 0.5 pH units, and Hernandez (2013) shows that the wood trees (those with bark similar to Eucalyptus coolabah) the bark within one tree has a variation of ~1 pH unit. The Bootle is uniformly decomposed for the first few centimetres, as (1983) and Tetréault (1999) report a range of pH for some judged by uniform colour and texture. These are the ones species, the mode of these ranges is 0.8 pH units for both that can be invaded by very fast-growing fungi when water is datasets. These four papers are consistent with the pH of one added. Most suitable samples of dead bark for myxomycete tree species generally having a range of less than ~1.8 pH cultivation the bark samples have a thin (1–2mmthick), units. A dataset of angiosperm timber pH has been constructed lighter, outer layer of much decomposed bark, on a thicker as follows. The Bootle (1983) data has been divided into three layer that is darker and appears to be little decomposed, datasets: tropical imported timber, Australian rainforest timber although dead. From appearance one would think that this from southern Queensland and northern New South Wales, thicker layer was less decomposed than aerial and ground and Australian Eucalyptus timber south of ~30S. The litter. However, the mean-pH data points on Fig. 3 for bark Tetréault (1999) data has also been divided into three have the same pattern as those for aerial and ground litter, and datasets: tropical trees, trees south of 50N and trees north are broadly consistent with a mean pH of 6.5 within the tropics, of 50N. The two papers include some of the same Tropical and a mean pH of 5.6 near 35 latitude. timber species. The latitude attributed to the samples is the To discuss the origin of the variation in pH of decayed tree mean of the species distribution area for non-tropical timber litter a set of measurements on non-decayed angiosperm species, and has been put as 10 for tropical timber species. timber/wood is used. Timber industry measurements for The Canberra dataset of Appendix 3 consists of one collection of local indigenous trees, and one of temperate exotic (northern hemisphere) trees. All these estimates of the mean x ○ liana stem pH for timber/wood are listed in Table 6 and plotted in Fig. 3. + aerial twigs A sample with only one genera (Eucalyptus) has a mean of x bark pH ○ 3.7; this low value is presumably characteristic of the genus, ◊ ground twigs and this data point is not discussed further. The majority of 7 x □ ground leafs the timber/wood mean values listed are for mixed genera, and decayed wood these have a pH range of only 4.6–5.1, and a mean of ~4.9. The ◊○ ○ x timber/wood  ○ x+ □ □ samples range in latitude from the equator to a latitude of 55 , □ +○ +□ □x◊□ ○ so there is no correlation of pH and latitude found for timber/ ◊+x ○ wood for mixed species samples. The simplest explanation for □ the correlations between pH and latitude differing between un- 6 □ ◊ decayed materials (timber/wood) and decayed materials (litter, + bark and rotten wood), is that the decay of the organic material resulted in a change in pH, with the amount of change varying with latitude. ◊◊ □ ◊ ◊ Conclusions 5 x x+ x◊ □ For surveys where the substrate is liana stems in closed forests, there were no significant differences in myxo species assemblages on substrates in forests with different altitudes above sea level, tropical or temperate climates, or collections from near ground to tree top level. Further, there were no significant differences between the species assemblages from 4 all the major types of litter substrate in closed angiosperm forests. Similarly, Wellman (2017) found that the myxomycete ( ) species associations collected by field surveys on wood in 0 10 20 30 40 50 60 closed temperate forests in the southern hemisphere and in the Latitude, north or south UK and Spain had the same species in the same relative Fig. 3. Relation between latitude and the mean acidity of myxomycete abundance. These observations are consistent with a model of substrates and timber. Data is listed in Table 2. The dashed line shows the similar ecological environments around the world having the inferred relationship for myxomycete substrates. The dotted lines show the same myxomycete species association within sampling error. relationships for northern hemisphere timbers (upper line), and southern The pH data from numerous published myxomycete hemisphere timbers (lower line). surveys can be modelled, such that the mean pH of a 42 Australian Journal of Botany P. Wellman species in a survey gives a residual from the model of 0.2 pH Hernandez V (2013) Radiata pine pH and buffering capacity: effect of age unit. As a consequence of this model the various myxo species and location in the stem. Maderas. Ciencia y Tecnología 15(1), 73–78. preferred pH relative to a standard survey mean of pH of 6.0 doi:10.4067/S0718-221X2013005000007 Ing B (1999) ‘The myxomycetes of Britain and Ireland.’ (The Richmond (pH6.0) can be determined. The preferred pH of the myxomycete species does not correlate with the presence of Publishing Co. Ltd: Slough, UK) Ko Ko TW, Stephenson SL, Hyde KD, Rojas C, Lumyong S (2010) Patterns lime in the fruiting bodies, but is generally constant within of occurrence of myxomycetes on lianas. Fungal Ecology 3, 302–310. genus. doi:10.1016/j.funeco.2009.11.005 Using subjective measures of hardness the Australian barks Lachowicz H, Wróblewska H, Sajdak M, Komorowicz H, Wojtaan R (2019) can be divided into hard, medium and soft, and for each The chemical composition of silver birch (Betula pendula Roth.) wood in myxomycete species the average hardness of its records can Poland depending on forest stand location and forest habitat type. – be determined. There is no apparent correlation of pH6.0 and Cellulose 26, 3047 3067. doi:10.1007/s10570-019-02306-2 average hardness values. This is consistent with the Lado C, Estrada-Torres A, Stephenson SL, Wrigley de Basanta D, myxomycete species differentiating in ecological niche both Schnittler M (2003) Biodiversity assessment of myxomycetes from two tropical forest reserves in Mexico. Fungal Diversity 12,67–110. by pH6.0 value, and preferred hardness. A fuller understanding of the controls on myxomycete species occurrence would Lado C, Wrigley de Basanta D, Estrada-Torres A (2011) Biodiversity of myxomycetes from the Monte Desert of Argentina. Anales del Jardin appear to come not from the substrates name or frequency Botanico de Madrid 68,61–95. doi:10.3989/ajbm.2266 but from the measurement for each sample of the chemical Leontyev DV, Schnittler M, Stephenson SL, Novozhilov YK, Shehepin ON (pH) and physical properties, where the preferred physical (2019) Towards a phylogenetic classification of the Myxomycetes. property is water holding capacity. Phytotaxa 399, 209–238. doi:10.11646/phytotaxa.399.3.5 In mixed angiosperm forests the (not-decayed) timber has a Massingill JM, Stephenson SL (2013) Myxomycetes appearing in moist mean pH of ~4.9 at latitudes of 0–55. The mean pH values for chamber cultures on samples of bark and wood collected from coarse decayed timber, bark and various types of litter all have a large woody debris. Mycosphere: Journal of Fungal Biology 4, 627–633. scatter. The average pH values of the decayed substrates do not doi:10.5943/mycosphere/4/3/14 fi McHugh R (2005) Moist chamber and field collections of Ecuador differ signi cantly from one another, and they have a mean – value of 6.5 in tropical latitudes and 5.6 at 35 latitude. The myxomycetes. Mycotaxon 92, 107 118. Novozhilov YK, Zemlianskaia IV, Schnittler M, Stephenson S (2006) data is consistent with the angiosperm timber increasing in pH Myxomycete diversity and ecology in the arid regions of the Lower on decay, with the amount of increase being greater at low Volga River Basin (Russia). Fungal Diversity 23, 193–241. latitude. Novozhilov YK, Erastova DA, Shchepin ON, Schnittler M, Alexandrova AV, Popov ES, Kuznetsov AN (2017a) Myxomycetes associated with Conflicts of interest monsoon lowland tropical forests in southern Vietnam. Nova Hedwigia – The author declares that he has no conflicts of interest. 104, 143 182. doi:10.1127/nova_hedwigia/2016/0395 Novozhilov YK, Schnittler M, Erastova DA, Shchepin ON (2017b) Declaration of funding Myxomycetes of the Sikhote-Alin State Nature Biosphere Reserve (Far East, Russia). Nova Hedwigia 104, 183–209. The research did not receive any specific funding. doi:10.1127/nova_hedwigia/2016/0394 Poulain M, Meyer M, Bozonnet J (2011) ‘Les myxomycÈtes.’ (Fédération Acknowledgements mycologique et botanique Dauphiné-Savoie: Sevrier, 2 volumes) Rosing WC, Mitchell DW, Stephenson SL (2007) Corticolous myxomycetes I thank the Australian National Herbarium for the use of laboratory facilities, from Victoria. Australasian Mycologist 26,9–15. and Christine Cargill and various librarians of the Australian National Schnittler M (2001) Ecology of myxomycetes of a winter-cold desert in Botanic Garden for support. The pH studies were much facilitated by western Kazakhstan. Mycologia 93, 653–669. Steve Stephenson giving permission for me to use the record spreadsheets doi:10.1080/00275514.2001.12063197 for published and unpublished surveys. I am grateful for the two reviews. Schnittler M, Stevenson SL (2000) Myxomycete diversity in four different – References forest types of Costa Rica. Mycologia 92, 626 637. doi:10.1080/00275514.2000.12061203 Black DR, Stephenson SL, Pearce CA (2004) Myxomycetes associated with Schnittler M, Tesmer J (2008) A habitat colonisation model for spore- the aerial litter microhabitat in tropical forests of northern Queensland, dispersed organisms - Does it work with eumycetozoans? Australia. Systematics and Geography of Plants 74, 129–132. Mycological Research112, 697–707. doi:10.1016/j.mycres.2008.01.012 Bootle KR (1983) ‘Wood in Australia, properties and uses.’ (McCraw Hill Schnittler M, Lado C, Stephenson SL (2002) Rapid biodiversity assessment Book Co: Sydney, NSW) of a tropical myxomycete assemblage - Maquipucuna Cloud Forest Camino M, Stephenson SL, Krivomaz T, Wrigley de Basanta D, Lado C, Reserve, Ecuador. Fungal Diversity 9, 135–167. Estrada-Torres A (2008) Biodiversity survey for myxomycetes in the Schnittler M, Unterseher M, Tesmer J (2006) Species richness and mountains of central Cuba. Revista Mexicana de Micología 27,39–51. ecological characterization of myxomycetes and myxomycete-like Cedeño M, Clayton M, Stephenson SL (2014) Woody twigs as a organisms in the canopy of a temperate deciduous forest. microhabitat for myxomycetes in the upland forests of Mycologia 98,223–232. doi:10.1080/15572536.2006.11832694 southwestern Virginia. 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Stephenson SL, Stephenson BC (2019) Distribution and ecology of Wellman P (2017) Temperate-climate myxomycetes in Australia and the myxomycetes on Christmas Island, Indian Ocean. Phytotaxa 416, Southern Hemisphere. Cunninghamia 17,1–13. 138–148. doi:10.11646/phytotaxa.416.2.2 Wellman P (2019) Australian corticolous myxomycetes: models of Stephenson SL, Stephenson BC (2020) Biodiversity of myxomycetes on distribution and development. Australian Journal of Botany 67, 617–629. Norfolk Island, South PacificOcean.Cunninghamia 20,115–121. doi:10.1071/BT19155 Stephenson SL, Urban LA, Rojas C, McDonald MS (2008) Myxomycetes Wikimedia (2020) World soil pH. Available at https://commons.wikimedia. associated with woody twigs. Revista Mexicana de Micología 27, org/wiki/File:World_Soil_pH.svg 21–28. Wrigley de Basanta D, Stephenson SL, Lado C, Estrada-Torres A, Nieves- Tetréault J (1999) Coatings for storage and display in museums. Canadian Rivera AM (2008) Lianas as a microhabitat for myxomycetes in Conservation Institute Technical Bulletin 21, Department of Canadian tropical forests. Fungal Diversity 28,109–125. Heritage, Ottawa, Canada. Wrigley de Basanta D, Lado C, Estrada-Torres A, Stephenson SL (2010) Walker LM (2016) Shifts in myxomycete community structure in selected Biodiversity of myxomycetes in subantarctic forests of Patagonia and microhabitats across nutrient treatments in lowland tropical forest of Tierra del Fuego, Argentina. Nova Hedwigia 90,45–79. Panama. University of Arkansas theses and dissertations, 1697. doi:10.1127/0029-5035/2010/0090-0045 Available at http://scholarworks.uark.edu/etd/1697 Wellman P (2016) Distinctive corticolous myxomycete assemblages of tropical, temperate and arid regions of Australia. Cunninghamia 16, 101–114. Handling Editor: Linda Broadhurst 44 Australian Journal of Botany P. Wellman

Appendix 1. List of sample details A list the sample numbers, name of liana, latitude, longitude, altitude, diameter of liana stems, and if known the pH of the stems 900A, Cissus antarctica, 35.603S, 150.324E, 52 m, d = 9 mm. 900B, unknown, 35.603S, 150.324E, 52 m, d = 10 mm. 900C, unknown, 35.603S, 150.324E, 52 m, d = 5 mm. 900D, Palmeria scandens, 35.603S, 150.324E, 52 m, d = 5 mm. 900E, unknown, 35.603S, 150.324E, 52 m, d = 10 mm. 900F, Eustrephus latifolius, 35.603S, 150.324E, 52 m, d = 1 mm. 900G, Smilax australis, 35.603S, 150.324E, 52 m, d = 7 mm. 900H, Cissus antarctica, 35.603S, 150.324E, 52 m, d = 4 mm. 900J, Cissus hypoglauca, 35.603S, 150.324E, 52 m, d = 3 mm. 900K, Smilax australis, 35.603S, 150.324E, 52 m, d = 5 mm. 933, Marsdenia flavescens, 36.615S, 150.029E,6m,d=9mm.934, Kennedia rubicunda, 36.615S, 150.029E, 6 m, d = 2 mm. 936, Aphanopetalum resinosum, 36.605S, 150.033E, 8 m, d = 5 mm. 937, Marsdenia rostrata, 36.605S, 150.033E, 8 m, d = 5 mm. 938, Sarcopetalum harveyanum, 36.605S, 150.033E, 8 m, d = 4 mm. 939, Eustrephus latifolius, 36.605S, 150.033E,8m,d=4mm.1115, Melodinus australis, 35.504S, 150.308E, 127 m, d = 4 mm. 1117, Parsonsia straminea, 35.635S, 150.281E, 32 m, d = 5 mm. 1118, Morinda jasminoides, 36.617S, 150.272E, 39 m, d = 5 mm. 1120, unknown, 36.617S, 150.272E, 39 m, d = 6.5 mm. 1121, Parsonsia straminea + Cissus hypoglauca, 36.617S, 150.272E, 39 m, d = 7 mm. 1123, Cissus hypoglauca, 36.617S, 150.272E, 39 m, d = 6 mm. 1124, Smilax australis, 37.413S, 149.812E, 222 m, d = 6 mm. 1125, Cissus hypoglauca, 37.413S, 149.812E, 222 m, d = 5 mm. 1126, Cissus hypoglauca, 37.413S, 149.812E, 222 m, d = 12 mm. 1127, Marsdenia rostrata, 37.415S, 149.815E, 202 m, d = 4 mm. 1128, Parsonia straminea, 37.415S, 149.815E, 202 m, d = 4 mm. 1431, Cissus antarctica, 32.233S, 152.554E, 31 m, d = 5 mm, pH = 5.9. 1432, Parsonsia straminea, 32.233S, 152.554E, 31 m, d = 4, pH = 6.2. 1433, unknown, 32.233S, 152.554E, 31 m, d = 5 mm, pH = 6.0. 1440, Parsonsia straminea, 30.368S, 152.795E, 716 m, d = 4 mm, pH = 5.5. 1441, Parsonsia straminea, 30.361S, 152.798E, 753 m, d = 6 mm. 1442, Stephania japonica, 30.41S, 153.075E, 5 m, d = 2 mm, pH = 6.6.

Appendix 2. List of myxomcete records This lists the myxomycete species recorded, the localities where they were found, and the number of fruiting bodies of each record. Arcyria cinerea (Bull.) Pers.; 900A, 55; 900D, 4; 900E, 230; 900F, 7; 900G, 4; 900H, 9; 900K, 42. Arcyria denudata Fr.; 900C, 91; 900E, 32; 900G, 10; 936, 2; 937, 8; 938, 6; 1118, 3; 1120, 8; 1124, 4; 1125, 3; 1126, 22; 1128, 6; 1433, 29; 1440, 2; 1442, 79. Arcyria insignis Kalchbr. and Cooke; 900H, 11;1117, 6; Arcyria pomiformis (Leers) Rostaf.; 900K, 13. Badhamia nitens Berk.; 900D, 8; 1431, 98. Clastoderma debaryanum A. Blytt; 900G, 1. Comatricha elegans (Racib.) G. Lister; 900A, 8; 1124, 5; 1440, 8. Comatricha ellae Härk.; 937, 3; Comatricha laxa Rostaf.; 900A, 2; 900F, 2; 900G cf, 87; 936, 1; 937, 9; 1118, 1; 1123, 3; 1433, 2. Comatricha pulchella (C. Bab.) Rostaf.; 900K, 10; 1121, 1. Comatricha sp; 1440, 4. Cribraria violacea Rex; 900H, 8. Didymium clavus (Alb. and Schwein.) Rabenh.; 1117 cf, 15. Didymium difforme (Pers.) Gray; 900F cf, 4; 934, 2. Didymium iridis (Ditmar) Fr.; 1432 cf, 33. Didymium squamulosum (Alb. and Schwein)Fr.; 900F,68; 934, 19; 1118, 2;1127, 72; 1442, 27.Didymium sp.;1125, 24.Echinosteliumminutum de Bary; 934,30, 936, 200;1118, 10; 1123,2; 1126, 10; 1431, 10; 1440, 12; 1441, 200. Hemitrichia pardina (Minakata) Ing; 1118, 4. Lamproderma arcyrionema Rostaf.; 900A, 5; 900D, 20; 900E, 12; 900F, 1; 900H, 2. Licea biforis Morgan; 900F, 12. Licea kleistobolus G. W. Martin; 900H, 10. Macbrideola declinata T. E. Brooks and H. W Keller; 1123, 8. Macbrideola sp.; 900G, 2; 900H, 1. Perichaena chrysosperma (Curr.) Lister; 900H, 18; 1118, 19. Perichaena depressa Lib.; 900A, 127; 900B, 12; 900H, 25; 1117 cf; 1; 1118, 31; 1433, 145. Perichaena sp.; 1120, 2. Perichaena vermicularis (Schwein) Rostaf. 934, 5; 1128, 16; 1432, 2; 1442, 16. Physarum compressum Alb. and Schwein.; 900A, 216; 900B, 195; 900F, 10; 933, 425; 934, 50; 937, 50; 1117, 16; 1125, 76; 1127, 50. Physarum hongkongense Chao H. Chung; 900E, 5. Physarum leucophaeum Fr.; 1118, 4; 1442, 22. Physarum melleum (Berk. and Broome) Massee; 900D, 105; 900H, 121; 900J, 50; 1118, 16. Physarum oblatum T. Macbr.; 900A, 327; 900D, 9; 900F, 81; 900H, 12; 900J, 24; 900K, 70; 933, 1; 937, 170; 1115, 4; 1117, 103; 1118, 12; 1120, 19; 1121, 5; 1124, 11; 1125, 7; 1126, 1; 1127, 6; 1128, 1; 1442, 350. Physarum pusillum (Berk. and M. A. Curtis) G. Lister; 900E, 23; 900B cf, 3; 934, 3; 1432, 5; 1433, 43. Physarum sp.; 936, 3; 1118, 1; 1123, 5; 1125, 2; 1126, 2; 1433, 5. Physarum viride (Bull.) Pers.; 900K cf, 2. Stemonitis fusca Roth; 900A, 34; 900C, 37; 900D, 3; 900E, 5; 900G, 17; 900H, 7; 900K, 1; 936, 12; 937, 7; 1118, 11; 1126, 13; 1440, 51; 1441, 29. Stemonitis mussooriensis G. W. Martin, K. S. Thind and Sohi; 900F, 24; 939, 13; 1125, 500; 1127, 70; 1432, 43; 1433, 15. Willkommlangea reticulata (Alb. and Schwein.) Kuntze; 900A, 45; 900D, 93; 900G, 4; 1431, 2.

Appendix 3. Additional pH measurements Asterisks (*) indicate trees exotic to Australia Wood and timber Grown in Canberra, 35S. Acacia dealbata, 4.7; Alnus glutinosa*, 5.4; Carya sp.*, 4.8; Casuarina cunninghamiana, 6.1; Eucalyptus globulus bicostata, 4.9; Eucalyptus delegatensis, 3.9; Eucalyptus marginata, 4.1; Eucalyptus polyanthemos, 5.2; Eucalyptus sideroxylon, 4.7; Exocarpus cupressiformis, 5.6; Gleditsia triconthos*, 5.2; Nothofagus cunninghamii, 3.9; Pinus radiata*, 4.6; Platanux acerifolia*, 5.7; Populus canescens*, 3.7; Populus lasiocarpa*, 4.9; Populus nigra ‘Italica’*, 6.7; Quercus  hispanica*, 5.6; Quercus robur*, 4.8; Salix fragilis*, 5.3; Ulmus procera*, 5.2. Decayed liana stem Grown in Canberra, 35S. Actinidia chinensis*, 6.1; Akebia quinata*, 6.8; Hardenbergia violacea, 5.8; Jasminum nudiflorum*, 6.7; Lonicera hildebrandiana*, 6.3; Pandorea jasminoides, 5.3; Pandorea pandorana, 5.6; Trachelospermum jasminoides*, 6.7; Vitus vinifera*, 6.7. NE New South Wales 32S. 1434, unknown, 7.0; 1436, Cissus antarctica, 6.1; 1437, Marsdenia rostrata, 6.2. Decayed branch wood Grown in Canberra 35S. Acacia sp., 4.9; Brachychiton populneus, 6.4; Casuarina sp., 4.7; Eucalyptus globulus, 5.0; Eucalyptus sp. 4.4, 5.3, 5.4; Exocarpus compressiformis, 5.1; Gleditsia triconthos*, 4.9; Quercus suber*, 5.0; Salix sp.*, 5.5; Tilia sp.*5.3; Ulmus sp.*, 5.3 Aerial litter – twigs Grown Canberra 35S. Brachychiton populneus, 6.6; Castanea sativa*, 5.7; Casuarina cunninghamiana, 5.1; Eriobotrya japonica*, 6.7; Eucalyptus cinomonum, 5.2; Eucalyptus mannifera, 5.0; Juglands nigra*, 5.6; Prunus sp.*, 5.8; Quercus suber*, 5.4; Tilia sp.*, 7.2; Ulmus procera*, 6.3; Ulmus sp. *, 5.6

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