Banksia serrata

Banksia serrata usually grows as a gnarled and misshapen tree up to 16 m (50 ft) tall, although in some coastal habitats it grows as a shrub of 1–3 m (3–10 ft), and on exposed coastal cliffs it has even been recorded as a prostrate shrub. As a tree it usually has a single, stout trunk with warty, knobbly grey bark up to 3 cm (1.2 in) thick. Trunks are often black from past bushfires, and ooze a red sap when injured. New growth appears in spring, summer and autumn. New branchlets are hairy, remaining so for two to three years. Leaves are usually crowded together at the upper end of branches, giving the canopy a thin, sparse appearance. The leaves themselves are dark glossy green above and light green below, —rarely up to —long by —rarely up to —wide, and oblong to obovate (egg-shaped) in shape. The leaf margins are serrated, except near the base, with lobes between deep. Cylindrical flower spikes, or inflorescences, grow from the ends of 1- to 2-year-old branchlets and have leaves at their base. The spikes are generally wide with hundreds of individual flowers arising from an upright woody axis. The woody axis is high and wide. The flowers are cream-grey in colour with cream styles. Old flower spikes develop into "cones" that consist of up to thirty follicles that develop from the flowers that were pollinated. Old withered flower parts remain on the cones, giving them a hairy appearance. Each follicle is oval in shape, wrinkled in texture, covered with fine hair and long, thick, and wide. == Taxonomy ==

Banksia serrata was first collected at Botany Bay on 29 April 1770, by Sir Joseph Banks and Daniel Solander, naturalists on the British vessel HMS Endeavour during Lieutenant (later Captain) James Cook's first voyage to the Pacific Ocean. Solander coined the (unpublished) binomial name Leucadendrum serratifolium, with Leucadendron serratum also appearing under the finished drawing in ''Banks' Florilegium. The first formal description of the species was not published until April 1782, when Carolus Linnaeus the Younger described the first four Banksia species in his Supplementum Plantarum, commenting that it was the showiest species in the genus. As the first named species of the genus, Banksia serrata'' is considered the type species. German botanist Joseph Gaertner described Banksia conchifera in 1788 in the first volume of his work De Fructibus et Seminibus Plantarum. Alex George noted this description was taken from Linnaeus' original and was hence a nomen illegitimum (illegitimate name). Under Brown's taxonomic arrangement, B. serrata was placed in subgenus Banksia verae, the "true banksias", because the inflorescence is a typical Banksia flower spike. Banksia verae was renamed Eubanksia by Stephan Endlicher in 1847, and demoted to sectional rank by Carl Meissner in his 1856 classification. Meissner further divided Eubanksia into four series, placing B. serrata in series Quercinae on the basis of its toothed leaves. When George Bentham published his 1870 arrangement in Flora Australiensis, he discarded Meissner's series, replacing them with four sections. B. serrata was placed in Orthostylis, a somewhat heterogeneous section containing 18 species. In 1891, Otto Kuntze, in his Revisio Generum Plantarum, rejected the generic name Banksia L.f., on the grounds that the name Banksia had previously been published in 1776 as Banksia J.R.Forst & G.Forst, referring to the genus now known as Pimelea. Kuntze proposed Sirmuellera as an alternative, referring to this species as Sirmuellera serrata. For the same reason, James Britten transferred the species to the genus Isostylis as Isostylis serrata in 1905. These applications of the principle of priority were largely ignored, and Banksia L.f. was formally conserved and Sirmuellera rejected in 1940. Current placement Alex George published a new taxonomic arrangement of Banksia in his 1981 monograph "The genus Banksia L.f. (Proteaceae)". In 1996, Kevin Thiele and Pauline Ladiges published a new arrangement for the genus, after cladistic analyses yielded a cladogram significantly different from George's arrangement. Thiele and Ladiges' arrangement retained B. serrata in series Banksia, placing it in B. subser. Banksia along with B. aemula as its sister taxon (united by their unusual seedling leaves) and B. ornata as its next closest relative. This arrangement stood until 1999, when George effectively reverted to his 1981 arrangement in his monograph for the Flora of Australia series. In 2005, Mast, Eric Jones and Shawn Havery published the results of their cladistic analyses of DNA sequence data for Banksia. They inferred a phylogeny greatly different from the accepted taxonomic arrangement, including finding Banksia to be paraphyletic with respect to Dryandra. A new taxonomic arrangement was not published at the time, but early in 2007 Mast and Thiele initiated a rearrangement by transferring Dryandra to Banksia, and publishing B. subg. Spathulatae for the species having spoon-shaped cotyledons; in this way they also redefined the autonym B. subg. Banksia. They foreshadowed publishing a full arrangement once DNA sampling of Dryandra was complete. In the meantime, if Mast and Thiele's nomenclatural changes are taken as an interim arrangement, then B. serrata is placed in B. subg. Banksia. Intraspecific variation Banksia serrata is a fairly uniform species, showing little variation between different habitats other than occasionally occurring as a shrub in coastal areas. No subspecific taxa are recognised. In his 1981 monograph, George was unable to locate a collection that corresponded with the report. == Distribution and habitat ==

Banksia serrata occurs on the Australian mainland from Wilsons Promontory, Victoria (39°08′ S) in the south, to Maryborough, Queensland (25°31′ S) in the north. There is also a large population at Sisters Creek in Tasmania and another in the southwest corner of the Wingaroo Nature Reserve in the northern part of Flinders Island. The Wingaroo NR Conservation Plan (2000) reports that the population comprises around 60 to 80 individual trees, the majority of which are believed to be "quite old". It adds that there is evidence of slow and continuous regeneration, which appears to be occurring in the absence of fire. Throughout its range, B. serrata is found on well-drained sandy soils that are low in nutrients, and it is often found on stabilised soil near the coast just behind the main dune system. In the Sydney region it is found with other typical woodland species, including yellow bloodwood (Corymbia eximia), red bloodwood (C. gummifera), silvertop ash (Eucalyptus sieberi), blue-leaved stringybark (E. agglomerata) and Sydney peppermint (E. piperita). B. serrata is a component of the Eastern Suburbs Banksia Scrub (ESBS), designated an endangered ecological community. This community is found on windblown sands, which are younger than the heathlands to the north. == Ecology ==

at flowers This species is a food source for several bird species. Nectar-eating birds that have been observed feeding at the flowers include bell miner (Manorina melanophrys), noisy miner (M. melanocephala), white-cheeked honeyeater (Phylidonyris nigra), New Holland honeyeater (P. novaehollandiae), crescent honeyeater (P. pyrrhopterus), white-eared honeyeater (Nesoptilotis leucotis), brown honeyeater (Lichmera indistincta), tawny-crowned honeyeater (Gliciphila melanops), white-naped honeyeater (Melithreptus lunatus), white-plumed honeyeater (Ptilotula penicillata), yellow-tufted honeyeater (Lichenostomus melanops), eastern spinebill (Acanthorhynchus tenuirostris), red wattlebird (Anthochaera carunculata), little wattlebird (A. chrysoptera), noisy friarbird (Philemon corniculatus), spangled drongo (Dicrurus bracteatus), and rainbow lorikeet (Trichoglossus moluccanus). A 1988 field study found that most flowers of B. serrata opened at night, and recorded the brown antechinus (Antechinus stuartii), sugar glider (Petaurus breviceps), eastern pygmy possum (Cercartetus nanus), and bush rat (Rattus fuscipes) as nocturnal mammalian visitors and pollinators. Other mammals recorded eating the flowers include the grey-headed flying fox (Pteropus poliocephalus), little red flying fox (P. scapulatus) and common blossom bat (Syconycteris australis). Native bees and European honey bees visit the flowers. These roots are particularly efficient at absorbing nutrients from nutrient-poor soils, such as the phosphorus-deficient native soils of Australia. Banksia serrata has shown a variable susceptibility to dieback from the pathogen Phytophthora cinnamomi, the plants in sandier soils showing more resistance than those in heavier soils. Plants from Wilsons Promontory were sensitive. The resistance of plants from Flinders Island is unknown. The small size of the stand renders it vulnerable to eradication. Response to fire Banksia serrata plants generally become fire tolerant by five to seven years of age in that they are able to resprout afterwards. Regrowth is generally from epicormic buds under their thick bark if the plant is between 2 and 6 m (7–20 ft) high or possibly from the woody subterranean base known as the lignotuber of younger and smaller plants. There is doubt as to whether recovery from a lignotuber is possible, although it has been demonstrated in other Banksia species such as B. menziesii. Stem size is a critical factor; stems with a DBH of under 1 cm (0.4 in) are unable to withstand low intensity fires. A stem/trunk DBH of 2 cm (0.8 in) is needed to survive low intensity fires and of around 5 cm (2 in) to withstand a high intensity fire. As with other species in the genus, B. serrata trees are naturally adapted to the presence of regular bushfires and exhibit a form of serotiny known as pyriscence. The seedbank in the plant's canopy is released after bushfire. Fire intervals of 10 to 15 years are recommended for the Eastern Suburbs Banksia Scrub, as longer leads to overgrowth by coastal tea tree (Leptospermum laevigatum), while an interval of at least nine years was indicated in a study at Brisbane Water National Park. Repeated intervals of five years' duration or less will result in decline of population as young plants are not yet resistant to fire, and their tall habit makes them especially vulnerable. Seeds are also released spontaneously in the absence of fire. The degree to which B. serrata trees exhibit bradyspory seems to depend on the nature of the site where they grow. One study recorded plants at coastal sites having more than 30% of their follicles open, compared to those further inland having fewer than 5% open. Follicles also open when part of the tree dies. == Uses ==

at the Royal Botanic Gardens, Cranbourne Use in horticulture The gnarled lumpy bark, saw-toothed leaves and silvery-yellow spikes in bud are horticultural features of B. serrata. In cultivation, though relatively resistant to P. cinnamomi dieback, it grows best in a well-drained soil, preferably fairly sandy with a pH from 5.5 to 7.5, and a sunny aspect. Summer watering aids in growth. The plant may take several years to flower, although plants grown from cuttings may flower in two years. Use in construction Red-pink in colour, the timber resembles English oak. • Banksia 'Superman' – selection from large-flowered (spikes to high) and large-leaved population from Scotts Head on New South Wales mid north coast. As yet, it is not in commercial cultivation, though is registered with ACRA. == Notes ==