Banksia oblongifolia
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Banksia oblongifolia,
Georges River National Park
Kingdom: Plantae
(unranked)
Angiosperms
:
(unranked)
Eudicots
:
Order: Proteales
Family: Proteaceae
Genus: Banksia
Subgenus: Banksia
Section: Banksia
Series: Salicinae
Species: B. oblongifolia
Banksia oblongifolia
Cav.
The Fern-leaved Banksia(Banksia oblongifolia) is a species of shrub in the plant genus Banksia. It occurs along the eastern coast of Australia
from Wollongong, New South Wales in the south to Rockhampton, Queensland in the north. It is also known as the Rusty Banksia, due to its rusty hairy new growth, or Dwarf Banksia, due to its small size compared with other banksias. It was known as Banksia asplenifolia, for many years but this was a nomen nudum.
Contents
[hide]
∙ 1 Description
∙ 2 Taxonomy
o 2.1 Placement within Banksia
o 2.2 Variation
∙ 3 Distribution and habitat
∙ 4 Ecology
∙ 5 Cultivation
∙ 6 References
∙7 External links
[edit] Description
Banksia oblongifolia is a shrub which can reach 3 m (10 ft) high,[1]though is generally less than 2 m (7 ft) high,[2] with veral stems growing out of a woody ba known as a lignotuber. The smooth bark is marked with horizontal lenticels, and is reddish brown fading to greyish brown with age. New leaves and branchlets are covered with a rusty fur. The leaves lo their hair and become smooth with maturity, and are alternately arranged along the stem. Measuring 5–11 cm (2-4.4 in) in length and 1.5–2 cm (0.6-0.8 in) wide, the leathery green leaves are oblong to obovate or truncate with a recesd midvein and mildly recurved margins, which are entire at the ba and rrate towards the ends of the leaves. The sinus are U-shaped and teeth are 1-2 mm long. The leaf underside is whitish with a reticulated vein patter and a raid central midrib.[3] The leaves sit on 2–5 mm long petioles. The inflorescences, or flower spikes, ari from the end of 1 to 5 year old branchlets, and often have a whorl of branchlets arising from the node or ba. Measuring 5 to 15 cm (2-6 in) high a
nd 4 cm wide, the yellow spikes often have blue-grey tinged limbs in bud,[1] though occasionally pinkish, mauve or mauve-blue limbs are en.[4]Opening to a pale yellow after anthesis, the spikes lo their flowers with age and swell to up to 17.5 cm (7 in) high and 4 cm (1.8 in) wide, with up to 80 follicles. covered with fine fur but becoming smooth with age, the
oval-shaped follicles measure 1–1.8 cm long by 0.2–0.7 cm high and 0.3–0.7 cm wide.[1]The bare swollen spike, now known as an infructescence, is patterned with short spiky persistent bracts on its surface where follicles have not developed.[3]
Banksia oblongifolia can be distinguished from B. robur, which it often co-occurs with, by its smaller leaves and bare fruiting spikes. B. robur has more metallic green flower spikes, and often grows in wetter areas within the same region.[1]
[edit] Taxonomy
First collected by Luis Née between March and April 1793, the fern-leaved banksia was described by Antonio José Cavanilles in 1800 twice from two collections, once as Banksia oblongifolia from the vicinity of Port Jackson(Sydney) and then as Banksia salicifolia from around Botany Bay. Derived from the Latin words oblongus "oblong", and folium "leaf", the species name relates to the shape of t
he leaves.[5]
For many years in New South Wales, the fern-leaved banksia had gone by the scientific name of Banksia aspleniifolia. Richard Anthony Salisbury had published this binomial name in 1796. Botanist and banksia authority Alex George conclusively established oblongifolia as the correct name to be ud in his 1981 revision of the genus. He pointed out that Salisbury's original described the leaves only, was insufficient to diagno the species and is hence a nomen dubium—the description could have fit juvenile leaves of B. paludosa, B. integrifolia or even B. marginata as well. In fact, Brown himlf had been unsure whether aspleniifolia applied to what he called Banksia oblongifolia.[1]
Brown ud the epithet oblongifolia in his taxonomic arrangement, placing the taxon in the subgenus Banksia verae, the "True Banksias", becau the inflorescence is a typical Banksia flower spike.[6]In 1870, George Bentham published a thorough revision of Banksia in his landmark publication Flora Australiensis. In Bentham's arrangement, the number of recognid Banksia species was reduced from 60 to 46. Bentham declared B. oblongifolia referrable to, and a synonym of, B. integrifolia. Bentham defined four ctions bad on leaf, style and pollen-prenter characters.
B. integrifolia was placed in ction Eubanksia.[7] New South Wales botanists Maiden and Camfield
described Banksia latifolia variety minor from a collection in Kogarah in 1898, later renamed as a subspecies of B. robur.[1]
[edit] Placement within Banksia
The current taxonomic arrangement of the Banksia genus is bad on botanist Alex George's 1999 monograph for the Flora of Australia book ries.[8] In this arrangement, B. oblongifolia is placed in Banksia subgenus Banksia, becau its inflorescences take the form of Banksia's characteristic flower spikes, ction Banksia becau of its straight styles, and ries Salicinae becau its inflorescences are cylindrical. In a morphological cladistic analysis published in 1994, Kevin Thiele placed it in the newly described subries Acclives along with
B. plagiocarpa, B. robur and B. dentata within the ries Salicinae.[9] However, this subgrouping of the Salicinae was not supported by George.[8] B. oblongifolia's placement within Banksia may be summarid as follows:
old bare spike with follicles, Stanwell Tops, NSW
Genus Banksia
Subgenus Isostylis
Subgenus Banksia
Section Oncostylis
Section Coccinea
Section Banksia
Series Grandes
Series Banksia
Series Crocinae
Series Prostratae
Series Cyrtostylis
Series Tetragonae
Series Bauerinae
Series Quercinae
Series Salicinae
B. dentata–B. aquilonia–B. integrifolia–B. plagiocarpa–
B. oblongifolia–B. robur–B. conferta–B. paludosa–
B. marginata–B. canei–B. saxicola
Since 1998, American botanist Austin Mast and co-authors have been publishing results of ongoing cladistic analys of DNA quence data for the subtribe Banksiinae, which then comprid genera Banksia and Dryandra. Their analys suggest a phylogeny that differs greatly from George's taxono
mic arrangement. Banksia oblongifolia resolves as the clost relative, or "sister", to B. robur, with B. plagiocarpa as next clost relative.[10][11][12]In 2007, Mast and Thiele rearranged the genus Banksia by merging Dryandra into it, and published B. subg. Spathulatae for the taxa having spoon-shaped cotyledons; thus B. subg. Banksia was redefined as encompassing taxa lacking 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, B. oblongifolia is placed in B. subg. Spathulatae.[13]
[edit] Variation
George noted that Banksia oblongifolia showed considerable variation in habit, and in 1987 Conran and Clifford parated the taxon into two subspecies. In examining populations in southern Queensland, they reported that the two forms were distinct in growth habit and habitat, and that they did not find any intermediate forms. As the name Banksia robur variety minor had been given to what turned out to be the taller form of B. oblongifolia, this (confusingly) became the name for the taller variety. They defined variety oblongifolia as a multistemmed shrub 0.5 to 1.3 m high, with leaves 3-11 cm long and 1-2.5 cm wide, and flower spikes 4-10 cm high. The habitat is swamps and swamp borders, or rarely sandstone ridges. Variety minor is a taller shrub 1-3.5 m high with leaves up to 16
cm long an spikes 6 to 14 cm high.It is an understory plant in sclerophyll forests, associated with Eucalyptus signata and Banksia spinulosa var. collina. Both subspecies occur throughout the range.[14] However George rejected the varieties. stating the variability was continuous.
[edit] Distribution and habitat
Banksia oblongifolia occurs along the eastern coast of Australia from Wollongong, New South Wales in the south to Rockhampton, Queensland in the north. There is an isolated population inland at Blackdown Tableland National Park, and also inland incursions at Grafton and in the Sydney Basin.[2]
