Abstract: The role of root channels in the occupation of deep soil profiles by jarrah (Eucalyptus marginata Sm.) forest in south-western Australia was explored by coring and excavation. In profiles derived from granite, major descending roots are confined to channels that extend vertically from fissures and conduits in the shallow subsurface caprock layer deep in the clay subsoil. The channels are permanent features of the profile and are occupied by successive generations of trees. The channels have a diameter of 1-300 mm, abundance of 3 5 m-2 (all channels) or 1 m-2 (large channels), and occupy 1% of a horizontal surface at 6 m. Each forest tree has potential access to 100-200 channels. Large roots, fine roots with root hairs, and decaying root remains occur in the channels. Only fine roots (less than Imm diam.) penetrate the clay matrix and occupy the entire profile down to basement at depths of up to 40 m. In profiles derived from dolerite, occupation of the deep clay by large and fine roots is diffuse and root channels are absent. The dissimilar mode of root occupation of the two profile types may be explained by the difference in bulk density. In providing avenues for access by large roots as well as preferential wetting, the root channels may play a dominant role in the water and salt balance of jarrah forests on the granitic profile.

Abstract: The response of 11 Casuarina species to salinity (NaCl) at germination (0, 20, 50, 200, 400 mM) and/or as seedlings (0, 75, 150 mM) was studied. Both the final germination percentage and germination rate were reduced in all species by increasing salinity. Treatment of seedlings tended to depress growth, increase the concentrations of Na and Cl in the woody stem and shoot tip and decrease K concentrations in the root and shoot. The species exhibited a wide range of responses to salinity, with some (e.g. C. equisetifolia) showing little growth reduction and no visible injury symptoms, and others (e.g. C. inophloia) showing greatly reduced growth accompanied by shoot tip chlorosis and/or death at 150 mM NaCl. Na and C1 concentrations in the shoot tip in sensitive species treated at 150 mM NaCl were 6-10 times higher than those of controls. In the more resistant species estimated shoot tip concentrations of these ions in plants treated at 150 mM NaCl were approximately the same as or less than those of the external medium. Na and C1 concentrations in the root were higher in these species than in the more sensitive species.

Abstract: Agathis robusta and Araucaria cunninghamii trees growing in a seasonal tropical climate in north Queensland produce late wood during cooler and drier periods. Vascular cambium growth rates fluctuate, and slow-growing trees may temporarily have inactive cambium around parts of the trunk so no growth ring is formed. Radiocarbon dates on old Agathis trees indicate that the frequency of ring formation is less than annual.

Abstract: The genus Lolium is represented in Australia by the following five species: L. perenne, L. multiflorum, L. rigidum, L. loliaceum and L. temulentum. L. remotum is probably extinct in Australia as it has been found only associated with flax crops which are no longer grown locally. Natural and bred hybrids between the three outcrossing species are also found, viz. L. multiflorum × L. perenne (= L. × hybridum), L. multijlorum × L. rigidum and L, perenne × L. rigidum. Earlier botanical treatments of the genus in Australia are reviewed. A diagnostic key, species descriptions and ecological notes are presented.

Abstract: Leaf fossils from five Tertiary and Quaternary deposits in Tasmania indicate that Nothofagus cunninghamii and N. moorei probably shared a common early Tertiary ancestor. Late Tertiary cooling in Tasmania and/or the onset of glaciations probably led to a reduction in leaf size resulting in the small leaves found in extant N. cunninghamii. Two phylogenies are suggested for N. cunninghamii and N. moorei evolution but there is not enough evidence at present to determine which is the most likely.

Abstract: The macrophytic vegetation of Tasmanian wetlands consists of forest, scrub, marginal herbland, tussock sedgeland, sedgeland, reed swamp and aquatic herbland. More than 80 taxa dominate or codominate in at least one division of at least one of the 530 wetlands from which data were obtained. Communities dominated by each of 16 of these taxa occur in 10 or more wetlands and vary in mean richness from 4 to 18 species, richness increasing towards the margins of wetlands, with the area of wetland, and with decreasing salinity. A combination of salinity and permanence indices explains over one-third of the floristic variation between these communities; within freshwater wetlands, pH has more influence than the permanence index. The Tasmanian wetland flora is a subset of that of mainland Australia. Most Tasmanian wetland plant communities probably occur on the Australian mainland. Many of the wetland vegetation types discriminated on the mainland do not occur in Tasmanian non-tidal wetlands.

Abstract: The floral biology of Ondinea purpurea, consisting of an apetalous subspecies and a newly discovered petaloid subspecies, has been investigated. Anthesis occurs over a 3-day period. First-day flowers are protogynous and characterized by colourful reflexed perianth and stamina1 parts. The pollen-receptive stigmas of first-day flowers secrete a fluid that fills the small stigmatic cup. As potential pollinators are attracted and attempt to land on the distally exposed gynoecium, they contact the stigmatic fluid which loosens pollen from the insect's body and pollination is achieved. Second- and third-day flowers are functionally staminate. On the basis of comparative reproductive anatomy and pollination syndromes the placement of Ondinea in the Nymphaeaceae s. str. is supported.

Abstract: Trees of Doryphora sassafras and Eucryphia moorei, growing in undisturbed, more or less single- species stands of cool temperate rainforest near the limits of their distribution, produce multiple stems from a swollen stem base that resembles a lignotuber. Both fine and large roots are also produced from the stem base. The stem base survives the death of the main stem and its root system and is thus able to vegetatively reproduce the original tree. Vegetative reproduction appears to compensate for the lack of seedling regeneration on the forest floor and results in ecologically stable and genetically conservative communities.

Abstract: Individuals of E. botryoides (nomenclature of eucalypts follows Chippendale 1976) form large lignotubers in a coastal area of high rainfall (c. 1200 mm per year) and relatively infertile siliceous sand. All plants in the area are regularly burnt and those of the seaward edge are exposed to saline winds. A multiple-stemmed (mallee) form of E. botryoides with a large (up to 6 m wide) plate-like lignotuber occurs where the combination of environmental effects is harshest. The lignotuber develops a plate-like form following the death of the upper surface and the consequent progression of decay downwards, so that growth is mainly restricted to its periphery and under surface. The lignotuber gives rise to many generations of stems, mainly from its periphery. New roots are also formed in association with the process of lignotuber extension and hence E. botryoides mallees are an example of vegetative reproduction in the genus Eucalyptus. The probable sequence of events in the development of plate-like lignotubers is outlined diagramatically. Genetical and environmental factors that are probably involved in this development are discussed. It has not been possible to assess satisfactorily the ages of large lignotubers by C14 dating techniques because of sampling difficulties. All decayed wood samples attached to buried parts of such lignotubers so far examined have been aged at less than 200 years.

Abstract: Growth rings were examined in trees of Callitrzs macleayana from the Atherton Tablelands in Queensland, Australia. The climate is tropical with a distinct dry season that induces regular annual growth rings. A correlation of 0 74 was found between annual ring widths and the duration of the wet seasons. The potential of this species for dendrochronological study is apparent.

Abstract: Banskia ornata F. Muell. is a common dominant in heaths in south-eastem Australia that are frequently swept by fires which kill the plants. Regeneration is only from seed, suggesting that the future of the species is almost completely fire-dependent. At maturity, a multiple fruit is formed consisting of a number of follicles attached to a central rachis. Each valve of the follicle consists of an exocarp comprising an epidermis with hair cells and some sclereid bundles; a mesocarp containing bundles of sclereids in which the microfibrils are almost transverse to the major cell axis; and an endocarp in which the innermost cells are fibrous in form and in which the microfibrils of cellulose are oriented mainly parallel to the longitudinal axis of the cell. Also present in the endocarp but abaxial to the fibrous sclereids are sclereid bundles that show similar microfibril orientation to the mesocarp sclereids. The junction between the valves of the follicle has a layer of interdigitating cells. A resinous substance together with phenols are present in and between these cells. Because of the difference in structure of the sclereids of the endocarp and of those of the mesocarp and exocarp, stresses develop between these tissues on desiccation. Events leading to the opening of the follicles are: (1) at maturity resin and phenols are secreted into the vascular elements at the base of the rachis, severing the vascular supply to the follicle; (2) with the advent of fire, the resin at the junction of the valves of the pericarp is destroyed, releasing the stress in the valves of the follicles, which reflex, allowing the release of seed. In B. marginata and B. Integrifolia, the anatomy of the valves of the follicle is basically similar to that of B. ornata. However, the follicles open without the intervention of fire. Thin-layer chromatography has shown that the resins extracted from the cells of the junction zone between the valves of the follicle of B. ornata are chemically different from those extracted from the non-fire-dependent species, suggesting that they may differ also in their physical properties.

Abstract: Seedlings of Pittosporum undulatum were grown under shade screens for 16 days at four flux densities: 97.8, 18.2, 3.4 and 0.4% full daylight, i.e. c. 420, 78, 14 and 2 W m-2. Seedlings showed moderate tolerance of shade: the growth compensation point for light was 1 .6% daylight, the leaf area ratio in full daylight was low (48.96 cm2 g-1) and when plants grown at 0.4% were compared with those grown at 97.8% full daylight and there was a fourfold increase in chlorophyll concentration. Leaves were thinner at the lowest flux density because the cells were deflated and there appeared to be only one row of palisade mesophyll cells. On the other hand, there was no large increase in leaf area ratio with shading, no alteration in the chlorophyll a/b ratio and no depression of net assimilation rate in full daylight. P. undulatum can endure shade but has a higher growth rate when grown at higher photon flux densities. P. undulatum is found predominantly in shade owing to the uneven dispersal of seed and the site-dependent survival of seedlings and not because shade is required for maximum growth.

Abstract: Twenty-six isolates, including that derived from the type strain, of Erynia neoaphidis (syn. Entomophthora aphidis) were compared with nine isolates of the new species Erynia kondoiensis and with isolates of the closely related aphid pathogens Erynia nouryi and Erynia delphacis. Characters studied were primary spore size, in vitro growth rates, pathogenicity for two species of aphid, total fatty acid composition of mycelium and spores, and electrophoretic mobilities of their isoenzymes. All four species were distinct, with biochemical characters providing the clearest separation. Very little intraspecific variation was found within E. neoaphidis but one isolate of E. kondoiensis was quite distinct from the others by electrophoretic analysis. Morphologically, E. kondoiensis is very similar to E. neoaphidis but has smaller primary spores and the mycelium contains a much higher proportion of C 12:0 fatty acid. E. kondoiensis causes epizootics in Acyrthosiphon kondoi populations in Australia but is rarely found in the sympatric A. pisum. In contrast, E. neoaphidis very frequently infects A. pisum.

Abstract: Embryo development following suspensor elongation was studied in three species of Araucaria: A. cunninghamii, A. heterophylla and A. bidwillii. The mature embryos of these species were compared with those of A. hunsteinii and species for which published data are available. In general outline, the embryogeny of Araucaria resembles that described for a number of other conifers. Differences are evident among species of Araucaria with respect to the following features of the mature embryo: overall size; relative lengths of the cotyledons, hypocotyl and root cap; cotyledon number; the presence of stomates; the extent and arrangement of the vascular and secretory tissues; and the state of differentiation of the vascular tissue. Consideration of all these features lends some support to the generally recognized division of the genus into four sections, although there is some evidence to suggest a relationship between the Eutacta and Intermedia species, on one hand, and the Columbea and Bunya species, on the other.

Abstract: The timing of new surface root growth in jarrah (Eucalyptus marginata) was followed for a 15-month period in the field. The periodicity of new root growth was similar for long roots, non-mycorrhizal and mycorrhizal root clusters. Root growth was initiated during two peak periods in spring (September-October) and following autumn rain (May-June). Little new root activity was recorded in late winter (August) or during summer drought. Rapid root growth occurred within 2 days of a storm (47 mm rain) in February. In addition, short roots formed after very light showers of rain (<5 mm) in late summer. Much of the framework for fine feeder roots was built up after autumn rain. In contrast to new long root growth which was equally spread between spring and late autumn, the majority of new mycorrhizal roots were produced from May to July. Root growth ceased when warm surface soils dried out and commenced when the soils were moist after rain. Much of the new root growth in jarrah occurred when the root pathogen Phytophthora cinnamomi was active in the soil.

Abstract: The present study provides the first evidence for the occurrence of natural hybrids between the wide- ranging species E. obliqua (series Obliquae) and the restricted Tasmanian endemic E. pulchella (series Piperitae). The progeny from one putative hybrid is shown to be intermediate between the progeny from the two parental species for virtually all characters examined. Principal component and likelihood analyses support this intermediacy of the hybrid progeny and suggest that no other species are involved in this hybrid system. The hybrid progeny shows greater variability than progeny from either parental species. Further, the hybrid tree has a lower seed output per capsule than trees of either parental species and therefore the hybrid tree appears to be at an evolutionary disadvantage. The two adult hybrids were found on the edge of shallow gullies on E. pulchella-dominated, north- facing slopes away from pure stands of E. obliqua. Some natural saplings outside the phenotypic range of either species were also found in the gullies. These results are most easily interpreted as suggesting that the intermediate trees examined originated from recent hybridization (possibly F1) following the migration of E. obliqua pollen into the range of E. pulchella. It is suggested that long-distance pollen migration of this type may be of evolutionary importance in allowing the colonization of suitable sites (in this case, small gullies) by advantageous genes or gene combinations from a distant species. The gene combinations of the pollen parent may be reselected from a segregating hybrid swarm.

Abstract: Storage reserves of the aestivating corms of Isoetes muelleri (Isoetaceae, Pteridophyta), stem tubers of Phylloglossum drummondii (Lycopodiaceae, Pteridophyta) and corms of Stylidium petiolare (Stylidiaceae, Dicotyledoneae) and Philydrella pygmaea (Philydraceae, Monocotyledoneae) were examined by chemical analysis, microscopy and scanning X-ray microanalysis. Concentrations of mineral elements (P, K, Ca, Mg, Na, Zn) in corm or stem tuber dry matter were similar to those recorded earlier for other bulbous, cormous and tuberous species, but levels of total N (31-32 mg/g dry matter) and protein (15-17% of corm fresh weight) were exceptionally high. Accumulation of mineral elements in developing replacement corms of S. petiolare showed precocious uptake of K, accumulation of Zn closely parallel to increases in dry weight, and most rapid accumulation of N, Mg and P during late corm filling, when tissues were dehydrating most rapidly. The dormant corms or stem tubers resembled seeds in small size (2-11 mg fresh weight), low water content (1-5% H20 in fresh weight) and the presence of closely packed starch grains (some species), lipid droplets and protein bodies in their storage parenchyma. Protein bodies contained 'soft', cluster-like (P. drummondii) or globoid-type (other three species) inclusions whose structure was often obscured due to leaching or dislodgement during specimen preparation. Point (0.5 µm2) microanalysis of protein bodies containing apparently intact inclusions indicated the latter to be especially rich in P, Ca, Mg, Zn and Mn (S. petiolare) or P, K, Ca and Zn (P. pygmaea). Storage reserves of seeds of S. petiolare (cotyledon tissue) and P. pygmaea (aleurone of endosperm) showed ultrastructural features closely similar to those of their respective corms.

Abstract: The fern genus Cheilanthes Sw. in Australia consists of 15 taxa. The range of variation of each species is discussed and the distribution presented in map form. Cheilanthes sieberi Kunze is recognized as having two subspecies, C. sieberi subsp. sieberi stat. nov, and C. sieberi subsp. pseudovellea Quirk & Chambers. Three long-overlooked species are now recognized and defined; they are C. nudiuscula (R.Br.) T. Moore, C. tenuissima Bailey and C. contigua Baker. Cheilanthes vellea (Aiton) F. Muell. is now recognized as C. brownii (R.Br.) Domin. The plant originally referred to as C. tenulfolia (Burm. f.) Sw. and previously regarded as extending from South-East Asia to the south coast of Australia is here recognized as two different species; the northern species extending from South-East Asia to northern Australia is regarded as C. tenuifolia (Burm. f.) Sw. s. str. and the isolated southern species as C. austrotenuifolia Quirk & Chambers.

Abstract: The first 40 amino acid sequences of the small subunit of ribulose bisphosphate carboxylase are given for 24 angiosperm species, three from each of eight families chosen because cytochrome c and plastocyanin sequences are already available Using computer methods, these data have been analysed to yield minimal phylogenetic Steiner trees A well defined minimal tree becomes apparent when data from all three proteins are combined The root of the minimal tree is indicated by the node where a gymnosperm joins The minimal tree is briefly compared with published phylogenies: in agreement is the divergence of the dicotyledons and monocotyledons from the root and the grouping of the Asteraceae and Caprifoliaceae; in disagreement, and a feature of all three proteins, is the close grouping of the Fabaceae with the Brassicaceae

Abstract: The development of the seed coat, seed wing and food reserve tissue of the female gametophyte was studied in four species of Araucaria: A. cunninghamii, A, heterophylla, A. bidwillii and A. hunsteinii. The means of seed dispersal in each of these species were also recorded. Comparisons were made among these species and others for which published data are available. The species differed with respect to the thickness of the seed coat and anatomical characteristics of the component layers; the thickness and nature of the nucellar layer; the relative degree of enlargement of non-fertilized ovules; the composition of the food reserves; the presence and nature of the seed wing; and the seed dispersal mechanism. The distribution of these features among the species of Araucaria for which data are available is consistent with the generally followed division of the genus into four sections.

Abstract: δ13C values are presented for the 10 closely related species of the endemic Australian genera Thyridolepis, Paraneurachne and Neurachne (Poaceae). The three Thyridolepis species exhibit values typical of C3 plants, Paraneurachne muelleri of C4 plants. The genus Neurachne is variable; five species have C*3 values while N. munroi is typically C*4. These results generally confirm previous anatomical observations showing that Neurachne appears to contain both C3 and C4 species. N. minor, however, while having C3 δ13C values, has leaf anatomy which suggests it is C4. N. minor may be a C3/C4 intermediate.

Abstract: Seedlings of Acacia dealbata were grown in pots containing a sandy loam and inoculated with a suspension of homogenized nodules collected from naturally occurring A. dealbata trees. Plants were maintained in a controlled environment growth room. The rate of acetylene reduction by intact plants was determined by placing pots inside 1 25 litre jars. Experiments were conducted after 12 weeks of growth when the plants had attained a steady acetylene reduction activity. The rate of ethylene production was linear for at least 3 h, and the Michaelis-Menten constant (Km) value was 3 87 kPa acetylene. The seedlings showed little diurnal variation in acetylene reduction activity when day and night lengths were 12 h, but activity declined when the dark period was extended to 15 h. Acetylene reduction activity was markedly affected by soil moisture, the optimum rate occurring between 25 and 50% of field capacity (33 kPa). A rapid decline in the rate of acetylene reduction occurred when 8 mg nitrate-N was added per pot. Acetylene reduction activity, dry matter yield and nitrogen uptake were adversely affected by induced soil salinity. The loss in acetylene reduction activity was highly correlated with the degree of soil salinization.

Abstract: Nutrient cycling by a 3-year-old Acacia holosericea plantation (1111 trees ha-1) was studied over a 13-month period. The gross accumulation of each nutrient in the various above-ground organs was calculated from the net increase over the study period plus the amounts lost by leaching and litterfall. Gross accumulation was greatest for calcium (22.4 kg ha-1), and potassium (18.8 kg ha-1), sodium (6.8 kg ha-1), followed by magnesium (5.2 kg ha-1). Biochemical recycling was greatest for calcium (10%) magnesium (8%), sodium (3%) and potassium (2%); however, this may be an overestimate as some of the apparent mobilization was undoubtedly due to leaching. Litter return accounted for 14% of the gross accumulation for potassium, 11% of magnesium, 10% of sodium and 9% of calcium. Litterfall accounted for 90% of the return of calcium to the soil and 75% of the return of magnesium. On the other hand, transfer in solution (leaching, surface wash) accounted for 88% of the return of sodium from the canopy to the soil and 59% of the return of potassium. Over the period 1 January 1979 to 28 February 1980 (total rainfall 2261 mm), the addition of nutrients in area precipitation was greatest for sodium (23.6 kg ha-1), followed by potassium (11.2 kg ha-1), calcium (6.8 kg ha-1) and magnesium (1.8 kg ha-1). Throughfall and stemflow increased the concentration of nutrients, such that the total nutrient addition to the soil was greatest for sodium (28.8 kg ha-1) followed by potassium (15.0 kg ha-1), calcium (7.0 kg ha-1) and magnesium (2.0 kg ha-1). These additions to the soil are significant in relation to the gross accumulation of these elements by Acacia holosericea.

Abstract: Ribulose bisphosphate carboxylase has been prepared from 50 species of angiosperms from 16 diverse families. In 35 preparations, well known 'bland leaf' methods were used but 15 species had 'pungent leaves' and for these a new preparative method is described. Automatic methods have been used to obtain N-terminal sequences (40 amino acids) of the small subunit (SSU) from all 50 species and the pattern of variability is discussed: 26 of 40 positions are variable to a degree similar to that found in plastocyanin and plant cytochrome c, i.e, an average of 3.7 different amino acids per variable site. These results, and the fact that sufficient protein can be obtained from 100 g of leaves, make a widespread phylogenetic survey of angiosperm SSU feasible and it is claimed that the method is at least as practicable as nucleic acid sequencing. A limited amount of sequencing has been carried out on the large subunit (LSU) but its low variability discourages a protein sequencing survey. Implications for gene structure and function are discussed and evidence is given that active LSU is derived from a precursor with 14 additional amino acids at the N-terminus. In SSU, variability of the two N- terminal amino acids suggests that they are not involved in the signals for removal of either the transit peptide or, in the RNA, of the intron, excision of one end of which depends on the codons for the invariable amino acids at positions 3 and 4. Evidence is also given that if the N-terminus of SSU is methionine, as is common, then it is modified and associated with a 'frayed' N-terminus.

Abstract: The responses of five Eucalyptus species (E. calophylla, E. globulus, E. maculata, E. marginata and E. resinifera) to four levels of calcium phosphate and three levels of lime (CaCO3) on a granitic pallid zone clay of pH 4.0 from a jarrah forest soil were examined in a glasshouse trial. In the presence of a complete fertilizer, except for lime and phosphate, seedlings made poor growth and had weak root systems with few fine roots. Application of calcium phosphate promoted shoot and root growth in all species. Application of lime had no effect on plant growth except at very high levels (7.1 g per kg soil), where it induced iron deficiency chlorosis in some species. All species achieved maximum yield with an application of calcium phosphate of between 30 and 300 mg per kg soil. Phosphorus concentrations in individual leaves and shoots were low (0.1-0.3%) and responded weakly to phosphate treatments. Phosphorus concentrations in stems responded strongly to increasing phosphate applications over the whole range of phosphate supply. We suggest that stem tissues may be used to indicate the phosphorus status of eucalypts.

Abstract: Floral development of Maidenia rubra was followed from initiation to maturity. Plants are dioecious. Both male and female inflorescences develop from complexes initiated subapically. Complexes have three meristematic components that include two inflorescence initials flanking a central primordium; these form sequentially in the axil of the preceding initial. The third component also produces an inflorescence and branches sympodially to form further floral initials that have a spiral arrangement. The female inflorescences produce a single flower only with an inferior, unilocular ovary and three sepals, staminodes and bifid stigma. In the locule, numerous bitegmic ovules, borne panetally, are produced. A male inflorescence produces hundreds of small flowers that are released and float to the surface individually. Each male flower has three sepals, a staminode and two stamens, each anther consisting of three locules with eight pollen grains. Prior to maturation, the anther wall breaks down leaving a membraneous layer that assists in binding the octad of pollen grains together. Both male and female inflorescences are enclosed in a pair of fused bracts. The floral morphology is compared with other closely related genera in the Hydrocharitaceae and the unique features are assessed.

Abstract: When Eucalyptus sieberi was grown in either a steamed or unsteamed krasnozem that suppressed Phytophthora cinnamomi root rot and repotted when either 6 or 12 weeks old in a larger container of inoculated sandy loam, seedling survival was significantly greater in the unsteamed treatments By varying the treatments in the inner core soil and outer inoculum jacket, substituting a biologically inert coarse sand in place of the krasnozem in the core, and using eucalypt species of varying disease tolerance while maintaining very strict hygiene conditions throughout these experiments, it was possible to either demonstrate or deduce that: (a) the seedlings were killed when infection spread into the major roots, root collar and lower stem; (b) the microflora in the unsteamed krasnozem appeared to slow down the decay process within the root, possibly when the fungus was attempting to establish itself within the root; (c) the phenotypic resistance of a seedling to root disease depended, inter alia, on its genetic resistance and on the microflora in the surrounding soil; (d) once the fungus was established in the suberized tissues the microflora in the external environment had no influence on disease

Abstract: A morphometric and chemical study was made of 24 populations of Richea scoparia and R. angustifolia from widespread locations in Tasmania. The analyses failed to demonstrate any clear-cut discontinuities between the two species. R. angustifolia should be submerged taxonomically within R. scoparia as it is encompassed by the latter's wider variation. The data are interpreted in terms of a cline of a highly variable species, with morphs disposed according to trends in alpine climates from south-west to north-east Tasmania. Superimposed on this cline is a grouping of populations into two sets related to geological substrates. These sets do not correspond to the taxonomic 'species'.

Abstract: Previous reports of nutritional and genetical effects on lignotuber development in eucalypts are summarized. Seedlings of two provenances of E. camaldulensis, one normally lignotuberous the other non-lignotuberous, were raised under combinations of nitrogen and phosphorus levels. When an effect of nitrogen on overall growth is taken into account, there is no additional effect of phosphorus on lignotuber size or plant height, but there is an effect on the number of branches. Lignotubers were not formed on plants of the southern provenance irrespective of the plane of nutrition. In the northern provenance the percentage of lignotuber-bearing seedlings was highest at high levels of phosphorus associated with low to intermediate levels of nitrogen. At high nitrogen levels there was no statistical effect of change in phosphorus level on percentage of lignotuber formation. Nitrogen supply appears to be the main controlling nutritional factor.