text: banksia grossa banksia grossa , commonly known as the coarse banksia , is a species of shrub in the plant family proteaceae endemic to southwest australia . it is one of fourteen species of banksia of the series abietinae , all of which bear predominantly cylindrical or oval inflorescences . collected in 1965 , it was described in 1981 by alex george . its thick leaves and large seeds distinguish it from other members of the abietinae , and are the basis of its species name . found in sand or sand over laterite among heath between eneabba and badgingarra in western australia , it grows as a many - stemmed shrub to 1 m ( 3 . 3 ft ) high with narrow leaves and oval brownish flower spikes up to 10 cm ( 4 in ) high , composed of hundreds of individual flowers . flowering occurs throughout the cooler months of march to september . flower spikes develop woody follicles which bear the seeds . after bushfire , banksia grossa regenerates from its woody lignotuber ; bushfires also stimulate the release of seeds , which germinate after disturbance . visitors to ( and likely pollinators of ) inflorescences include insects and a nocturnal mammal , the white - tailed . description banksia grossa grows as a bushy shrub , generally 70 to 1 m ( 2 , 756 to 39 in ) high , or occasionally up to 1 . 5 m ( 4 . 9 ft ) high . its many stems rise from a woody lignotuber . young stems have a coating of woolly hairs , while older stems are covered in flaky pale brown bark . borne on 3 to 5 mm long petioles , the somewhat fleshy leaves are needle - like . although they are between 4 to 12 cm ( 1 . 5 to 4 . 5 in ) long , and only 2 to 3 mm wide , they are still thicker than those of other members of the series abietinae . the margins of the leaves are straight with no teeth and rolled over , and the upper surfaces are sparsely hairy when young , but later hairless . new growth occurs over spring and early summer . flowers occur in a typical banksia flower spike : an inflorescence made up of hundreds of small individual flowers , or florets , densely packed around ( and completely obscuring ) a woody cylindrical axis . in b. grossa , this axis is 5 to 7 cm ( 2 to 3 in ) high with a diameter of 0 . 7 – 0 . 9 cm ( 0 . 28 – 0 . 35 in ) . from this , the florets radiate out laterally , giving the inflorescence a diameter of 8 or 9 cm ( 3 or 3 . 5 in ) . flowers are rusty brown to golden brown , and consist of a hairy 3 . 4 – 4 . 5 cm ( 1 . 3 – 1 . 8 in ) long tubular perianth which opens at maturity ( anthesis ) to release the dark red to purple style . 3 . 8 – 4 . 8 cm ( 1 . 5 – 1 . 9 in ) long , the style extends past the perianth and is curved at the tip . the flower spikes arise from short thick branchlets running off larger stems , though some flower spikes are terminal ( located at the ends of branches and more prominently displayed in the foliage ) . flowering occurs between march and september , though early flowering in december has been recorded . it takes five to eight weeks for a flower to develop from bud to the end of flowering . about three weeks before the flowers open , they develop a strong musky smell . the opening of flowers occurs sequentially , starting at the bottom of the inflorescence and sweeping through to the top over a period of around two weeks . at anthesis the flowers produce copious quantities of nectar ; indeed , some flowers produce so much that it drips to the ground . after flowering , the old florets wither and curl against the spike , giving it a hairy appearance . now known as an infructescence , it is roughly ellipsoidal , 6 to 10 cm high ( 2 . 2 – 4 in ) and 4 to 8 cm ( 1 . 5 to 3 in ) wide . up to 25 smooth , elliptical follicles develop on the spike , each containing up to two wide wedge - shaped winged seeds . one field study revealed , on average , eight follicles for each fertile cone . initially covered in fine fur , these are 2 to 4 . 5 cm ( 0 . 79 to 1 . 77 in ) long , 1 – 1 . 8 cm ( 0 . 39 – 0 . 71 in ) high and jut out by 1 – 1 . 8 cm ( 0 . 39 – 0 . 71 in ) . the fur rubs off and they become smooth with wear , and generally remain closed until opened by fire . the seeds of banksia grossa are the largest of all the species of the series abietinae . measuring 2 . 8 – 3 . 9 cm ( 1 . 1 – 1 . 5 in ) long , they are made up of a cuneate ( wedge - shaped ) seed body , 1 . 4 – 1 . 8 cm ( 0 . 55 – 0 . 71 in ) long by 0 . 4 – 0 . 9 cm ( 0 . 16 – 0 . 35 in ) wide , and a 2 . 7 – 3 . 3 cm ( 1 . 1 – 1 . 3 in ) wide wing . the woody separator is the same shape as the seed , with an impression where the seed body lies next to it . the bright green cotyledons are obovate and can be either convex or concave , measuring 1 . 6 to 2 . 2 cm long by 0 . 9 to 1 . 2 cm wide . these arise from a stocky seedling stem , known as the hypocotyl , which is reddish and covered in short hairs . the auricles of the cotyledons are 2 mm long . seedling leaves arise 0 . 6 to 0 . 8 cm beyond the cotyledons and are oppositely arranged . linear , they are 1 . 4 to 1 . 6 cm long with recurved margins and are covered in white hair . the stem remains reddish . subsequent leaf pairs are successively longer . taxonomy the first known specimen collection of b. grossa was made by botanist fred w. humphreys in 1965 . alex george has expressed surprise that it was not collected by earlier visitors to the area , speculating that " perhaps they were diverted by its similarity to b. leptophylla and b. sphaerocarpa . " george formally described the species in his 1981 monograph " the genus banksia l.f. ( proteaceae ) " , based on a specimen collected by him on the brand highway , 76 km north of regans ford , on 14 may 1969 . he placed it in subgenus banksia because of its flower spike ; section oncostylis because its styles are hooked ; and the resurrected series abietinae , which he constrained to contain only round - fruited species . it was placed in phyletic order between b. micrantha and b. leptophylla . the specific epithet is from the latin ( " coarse " ) and refers to the leaves , flowers and fruit , all of which george observed were more coarse than other members of b. ser . abietinae . george 's arrangement remained current until 1996 , when kevin thiele and pauline ladiges published an arrangement informed by a cladistic analysis of morphological characteristics . they retained george 's subgenera and many of his series , but discarded his sections . banksia ser . abietinae was found to be very nearly monophyletic , and so was retained . it further resolved into four subclades , so thiele and ladiges split it into four subseries . banksia grossa appeared as the most basal member of the second of these : this clade became the basis for the new subseries , which thiele defined as containing those species with lignotubers , styles loosely curling around the infructescence ( although this trait was reversed in b. micrantha ) , and " transversely aligned cells of the seed wing inner face " . the species other than b. grossa also have shouldered follicles . questioning the emphasis on cladistics in thiele and ladiges ' arrangement , george published a slightly modified version of his 1981 arrangement in his 1999 treatment of banksia for the flora of australia series of monographs . the placement of b. grossa was the same as in 1981 , except that b. telmatiaea was moved to set between it and b. leptophylla . the placement of b. grossa in george 's 1999 arrangement may be summarised as follows : banksia b. subg . banksia b. sect . banksia ( 9 series , 50 species , 9 subspecies , 3 varieties ) b. sect . coccinea ( 1 species ) b. sect . oncostylis b. ser . spicigerae ( 7 species , 2 subspecies , 4 varieties ) b. ser . tricuspidae ( 1 species ) b. ser . dryandroideae ( 1 species ) b. ser . abietinae b. sphaerocarpa ( 5 varieties ) b. micrantha b. grossa b. telmatiaea b. leptophylla ( 2 varieties ) b. lanata b. scabrella b. violacea b. incana b. laricina b. pulchella b. meisneri ( 2 subspecies ) b. nutans ( 2 varieties ) b. subg . isostylis ( 3 species ) since 1998 , austin mast has been publishing results of ongoing cladistic analyses of dna sequence data for the subtribe banksiinae . his analyses suggest a phylogeny that is very different from george 's arrangement . banksia grossa was inferred to be sister to a polytomous clade consisting of b. leptophylla , b. telmatiaea , b. scabrella and b. lanata : early in 2007 , mast and thiele initiated a rearrangement of banksia by merging dryandra into it , and publishing b. subg . spathulatae for the taxa having spoon - shaped cotyledons . 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. grossa is placed in b. subg . spathulatae . distribution and habitat banksia grossa mainly occurs from west of in the north , south to badgingarra national park , and east almost to . it grows in shallow sand over laterite , in deep sand , and occasionally atop lateritic rises , on flat or gently undulating land , among kwongan shrubland . around 40 % of plants occur on road verges . ecology banksia grossa resprouts from its woody lignotuber after bushfire . shrubs carry relatively low numbers of seeds compared with plant species that regenerate by seed after bushfire . a field study in eneabba showed shrubs bore anywhere from 30 to 90 seeds per plant . seeds borne on plants , however , are less likely to be eaten by animals than seed lying dormant in the soil , and hence survive to produce future seedlings . populations of resprouting plants , like b. grossa , benefit more from longer intervals between fires as their stored seedbank takes longer to accumulate than reseeding species . the follicles generally open after bushfire , releasing seeds which germinate after disturbance . species with persistent flowers on old spikes often require higher temperatures for follicles to open after burning ; laboratory testing resulted in 50 % opening after exposure to 270 ° c and 90 % after 400 ° c. the leaves of b. grossa are adapted to a dry climate . the lower surfaces are protected by the strongly revolute shape of the leaf , the leaf margins curling around underneath almost to the mid - vein . the trichomes ( leaf hairs ) run along the mid - vein and the margins , further protecting the surface where the are located , thus minimising water loss . cladistic analysis suggests this species and its relatives in the series abietinae developed long narrow leaves with inrolled margins as they invaded drier climates in australia 's southwest , having evolved from ancestors with broad leaves . the inflorescences are highly attractive to insects . the rare bee species hylaeus is a recorded visitor . large numbers of ladybirds have been reported drinking the nectar of this species , while ignoring nearby banksia attenuata inflorescences . the white - tailed ( ) has been observed visiting flower spikes . pollen has been found on the snouts and in the scat of several species of marsupials , which suggests these animals are likely pollinators of banksia species in general . no pollinators of this species were recorded in the banksia atlas survey . banksia grossa is one of five closely related banksia species that have highly unusual flower nectar . whereas other banksia species produce nectar that is clear and watery , the nectar of these species is pale yellow initially , but gradually becomes darker and thicker , changing to a thick , olive - green mucilage within one to two days of secretion , and eventually becoming " an almost black , gelatinous lump adhering to the base of the flowers " . it was first noted by byron lamont in 1980 ; he attributed it to cyanobacteria that feed off the nectar sugars . noting that many of these cyanobacteria had heterocysts , he speculated that they aid the plant by fixing atmospheric nitrogen , which is then washed off the flower heads by rain , and absorbed by the proteoid root mat . this purported symbiosis was investigated by barrett and lamont in 1985 , but no evidence of nitrogen fixing was found . further investigation by markey and lamont in 1996 suggested that the discolouration is not caused by cyanobacteria or other microorganisms in the nectar , but is rather " a chemical phenomenon of plant origin " . their analyses indicated that the nectar had unusually high levels of sugar and free amino acids , but three of these species , including b. sphaerocarpa , have since been shown to have normal nectar sugar compositions . the purpose of coloured nectar is unclear , especially as pollinators such as nocturnal mammals are not thought to forage by sight . however , nectar that becomes more obvious by appearance or smell as it ages might encourage pollinators to prioritise it over newer nectar . it is possible the colour change is unrelated to pollination . cultivation banksia grossa is cultivated for its attractive needle - like leaves and rusty - brown flower spikes , both of which can be quite variable in colour . this species favours well - drained sandy or loamy acidic soils with a ph of 5 . 5 to 7 , and a sunny aspect . once established , it tolerates dry spells . it can be pruned heavily as it resprouts from its lignotuber . propagation is by seed . the seeds do not require any treatment before sowing , and take around 14 days to germinate . this is a slow - growing plant , taking 5 to 7 years to reach maturity and begin flowering .