Banksia scabrella, commonly known as the Burma Road banksia, is a species of woody shrub in the genus Banksia. It is classified in the series Abietinae, a group of several species of shrubs with small round or oval inflorescences. It occurs in a number of isolated populations south of Geraldton, Western Australia, with the largest population being south and east of Mount Adams. Found on sandy soils in heathland or shrubland, it grows to 2m (7ft) high and 3m (10ft) across with fine needle-like leaves. Appearing in spring and summer, the inflorescences are round to oval in shape and tan to cream with purple styles. Banksia scabrella is killed by fire and regenerates by seed.
Originally collected in 1966, B. scabrella was one of several species previously considered to be forms of Banksia sphaerocarpa, before it was finally described by banksia expert Alex George in his 1981 revision of the genus. Like many members of the Abietinae, it is rarely seen in cultivation; however, it has been described as having horticultural potential.
Description
Banksia scabrella grows as a low shrub to 2m (6.6ft) in height and 3m (9.8ft) across, with a spreading habit. Its lateral branches are low and often rest on the ground. The small linear leaves measure 0.8 to 2.8cm in length and 0.1cm in width and are crowded along the stems. George recorded flowering as occurring in spring and summer (September to January),[1] but The Banksia Atlas recorded the species in bloom in April.[2] Flowers occur in "flower spikes", or inflorescences, made up of hundreds of small flowers, or florets, densely packed around a woody axis. Quite conspicuous, they are terminal (occurring on the ends of branches) or on short side branchlets. Round or oval in shape, the cream or tan inflorescences are 3 to 6cm (1.2 to 2.4in) high and 7–9cm (2.8–3.5in) wide. The individual flowers are light yellow or cream, with the styles and upper floral parts purple. The perianths measure 2.7 to 3.5cm (1.1 to 1.4in), while the pistils 3.4 to 4.5cm (1.3 to 1.8in) in length and are curved at the apex. The inflorescences fade to grey as they age and the old flowers do not fall off. Up to 80 follicles develop on one spike, and remain closed until opened after a bushfire.[1][3] Oval-shaped, they measure 1.8–2.8cm (0.71–1.10in) in length, by 0.5–0.9cm (0.20–0.35in) high, and0.6–0.8cm (0.24–0.31in) wide. They open to release a dark brown oval seed 1.3–1.5cm (0.51–0.59in) long, 0.4–0.5cm (0.16–0.20in) wide with a papery dark 'wing' 1.4–2.4cm (0.55–0.94in) wide.[1] Seedlings have narrowly obovate bright green cotyledons1.2–1.4cm (0.47–0.55in) long by 0.3–0.4cm (0.12–0.16in) wide, and the leaves which develop immediately afterward are linear and scattered, and the stem is hairy.[1]
First collected on 4 September 1966, southeast of Walkaway, Banksia scabrella was described by Alex George in his 1981 revision of the genus Banksia. He gave it the epithet scabrella, a diminutive of the Latin adjective scaber "rough", referring to the leaves. George placed B.scabrella 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. He initially thought its closest relative to be Banksia leptophylla, which is found in the same region,[1] and later felt it to be B. lanata, which has similarly coloured inflorescences but longer smooth leaves.[3] It was one of several new species previously regarded as a form of Banksia sphaerocarpa.[4]
In 1996, botanists 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 retained. It further resolved into four subclades, so Thiele and Ladiges split it into four subseries. Banksia scabrella appeared in the third of these, initially called the "telmatiaea clade" for its most basal member. As with George's classification, B.lanata and two subspecies of B.leptophylla emerged as close relatives of B.scabrella, but there was some question over the relationships between all five forms in the clade.[5]
This clade became the basis for a new subseries Leptophyllae, which Thiele defined as containing species with "indurated and spinescent common bracts on the infructescence axes", and seedling stems which were densely arachnose (covered in fine hair).[5] Thiele and Ladiges' arrangement was not accepted by George, and was largely discarded by him in his 1999 arrangement. B.ser. Abietinae was restored to George's 1981 circumscription, and all of Thiele and Ladiges' subseries were abandoned. The placement of B.scabrella in George's 1999 arrangement may be summarised as follows:[3]
Bud developing on stems on ground, road verge, Burma Road
A 2002 study by American botanists Austin Mast and Tom Givnish concurred with Alex George's observations in that molecular analysis mapped out scabrella as one of a clade containing B.lanata, both subspecies of B.leptophylla and B.telmatiaea, with B.grossa as a more distant relative.[6] 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.scabrella is placed in B.subg. Spathulatae.[7]
Distribution and habitat
Distribution of Banksia scabrella. Lower region is that near Mount Adams.
Banksia scabrella is found in two disjunct areas of scattered populations; the first discovered being southeast of the small town of Walkaway south of Geraldton, while a more populous cluster is found southeast of Mount Adams in Western Australia.[1] The average annual rainfall over its range is around 450mm (18in).[8] It has been placed on the Declared Rare and Priority Flora List, where it is classified as a "Priority Four – Rare" taxon; although it is rare, it is not currently threatened by any identifiable factors.[9] These taxa require monitoring every 5 to 10 years.[10] Many stands are populous, and number over 100 plants. However, over half the known population of B. scabrella is found on road verges.[2] Found in deep pale yellow or white sand in kwongan scrubland and heathland,[1]B. scabrella grows on flat areas or gentle slopes and is found in association with B. leptophylla and a dwarf form of B. attenuata.[2]
Most Proteaceae and all Banksia species, including B.scabrella, have proteoid roots, roots with dense clusters of short lateral rootlets that form a mat in the soil just below the leaf litter. These roots are particularly efficient at absorbing nutrients from nutrient-poor soils, such as the phosphorus-deficient native soils of Australia.[11]B.scabrella is highly susceptible to Phytophthora cinnamomi dieback.[12]
Killed by fire, the species regenerates from seed afterwards.[3] The resultant seedlings have been recorded flowering two or three years after bushfires, although records are few.[2] No pollinators were recorded during observations for the Banksia Atlas,[2] although banksia flowerheads in general play host to a variety of birds, mammals and insects.[13]
The region between Geraldton and Gingin is a rich one for Abietinae banksias, and nine species occur there. Despite this, there is little overlap in range and habitat; Banksia scabrella is unusual in its co-occurrence with B. leptophylla.[1] It is also associated with the endangered heath shrub Leucopogon marginatus.[14]Burma Road Nature Reserve is one of the few protected conservation areas in its range; there, Banksia scabrella is found most commonly in (and forms a prominent part of) a mallee sedgeland, which is dominated by the cord rush Ecdeiocolea monostachya as a ground cover, and the malleeEucalyptus eudesmoides as an emergent species. It is found occasionally in acaciascrub-heath, and rarely in acacia thickets and banksia woodland.[15] An assessment of the potential impact of climate change on this species found that its range is unlikely to contract and may actually grow, depending on how effectively it migrates into newly habitable areas.[16]
Cultivation
Seeds do not require any treatment, and take 14 to 16 days to germinate.[17] Rarely cultivated, Banksia scabrella flowers in 3 to 5 years from seed.[18] Information is limited on its reliability, but it has been grown successfully in South Australia.[8] It is fast-growing but ultimately untidy in habit, and would benefit from regular pruning. Some forms in the wild have a more compact habit, and are more promising for horticulture.[18]
↑ Mast, Austin R; Thiele, Kevin (2007). "The transfer of Dryandra R.Br. to Banksia L.f. (Proteaceae)". Australian Systematic Botany. 20 (1): 63–71. doi:10.1071/SB06016.
↑ Foulds, Bill; McMillan, Peter (1988). Burma Road Reserve report 1988: An ecological study of Burma Road Reserve, Greenough Shire, Western Australia. Perth: Western Australian College of Advanced Education. pp.60, 67. NBD6563629 (Libraries Australia id).
↑ Fitzpatrick, Matthew C.; Gove, Aaron D.; Sanders Nathan J.; Dunn, Robert D. (2008). "Climate change, plant migration, and range collapse in a global biodiversity hotspot: the Banksia (Proteaceae) of Western Australia". Global Change Biology. 14 (6): 1–16. Bibcode:2008GCBio..14.1337F. doi:10.1111/j.1365-2486.2008.01559.x.
↑ Sweedman, Luke; Merritt, David. (2006). Australian Seeds: A Guide to their Collection, Identification and Biology. CSIRO Publishing. p.203. ISBN978-0-643-09298-3.
1 2 Collins, Kevin; Collins, Kathy; George, Alex S. (2008). Banksias. Melbourne, Victoria: Bloomings Books. pp.321–22. ISBN978-1-876473-68-6.
Banksia subg. Banksia is a valid botanic name for a subgenus of Banksia. As an autonym, it necessarily contains the type species of Banksia, B. serrata. Within this constraint, however, there have been various circumscriptions.
As with other flowering plants, the taxonomy of Banksia has traditionally been based on anatomical and morphological properties of the Banksia flower, fruiting structure and seed, along with secondary characteristics such as leaf structure and growth habit. Increasingly, molecular evidence from DNA is providing important new insights into relationships within the genus and between this and other genera in the Proteaceae.
Banksia aculeata, commonly known as prickly banksia, is a species of plant of the family Proteaceae native to the Stirling Range in the southwest of Western Australia. A shrub up to 2 m (7 ft) tall, it has dense foliage and leaves with very prickly serrated margins. Its unusual pinkish, pendent (hanging) flower spikes, known as inflorescences, are generally hidden in the foliage and appear during the early summer. Although it was collected by the naturalist James Drummond in the 1840s, Banksia aculeata was not formally described until 1981, by Alex George in his monograph of the genus.
Banksia caleyi, commonly known as Caley's banksia or red lantern banksia, is a species of woody shrub of the family Proteaceae native to Western Australia. It generally grows as a dense shrub up to 2 m (7 ft) tall, has serrated leaves and red, pendent (hanging) inflorescences which are generally hidden in the foliage. First described by Scottish naturalist Robert Brown in 1830, Banksia caleyi was named in honour of the English botanist George Caley. No subspecies are recognised. It is one of three or four related species with hanging inflorescences, which is an unusual feature within the genus.
Banksia dryandroides, the dryandra-leaved banksia, is a species of small shrub in the plant genus Banksia. The Noongar peoples know the tree as manyat. It occurs in shrubland, woodland and kwongan on the south coast of Western Australia between Narrikup and Beaufort Inlet. The species is placed alone in series B. ser. Dryandroideae.
Banksia grossa is a species of shrub in the family Proteaceae and is 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 first formally 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.
Banksia lemanniana, the yellow lantern banksia or Lemann's banksia, is a species of flowering plant in the family Proteaceae, native to Western Australia. It generally grows as an open woody shrub or small tree to 5 m (16 ft) high, with stiff serrated leaves and unusual hanging inflorescences. Flowering occurs over summer, the greenish buds developing into oval flower spikes before turning grey and developing the characteristic large woody follicles. It occurs within and just east of the Fitzgerald River National Park on the southern coast of the state. B. lemanniana is killed by bushfire and regenerates from seed.
Banksia media, the southern plains banksia or golden stalk banksia, is a species of flowering plant in the family Proteaceae. An evergreen shrub, it occurs on the south coast of Western Australia between Albany and Israelite Bay, where it is a common plant. A many-branched bush with wedge-shaped serrated leaves and large golden-yellow flower spikes, known as inflorescences, it grows up to 10 metres (30 ft) high.
Banksia nutans, commonly known as nodding banksia, is a species of shrub native to the south coast of Western Australia in the genus Banksia. Growing to a metre (3 ft) tall, it has pale blue-green fine-leaved foliage and unusual purple-brown inflorescences which hang upside down rather than grow upright like most other banksias.
Banksia praemorsa, commonly known as the cut-leaf banksia, is a species of shrub or tree in the plant genus Banksia. It occurs in a few isolated populations on the south coast of Western Australia between Albany and Cape Riche.
Banksia sphaerocarpa, commonly known as the fox banksia or round-fruit banksia, is a species of shrub or tree in the plant genus Banksia. It is generally encountered as a 1–2 m (3.3–6.6 ft) high shrub, and is usually smaller in the north of its range. This species has narrow green leaves, and brownish, orange or yellow round flower spikes which may be seen from January to July. It is widely distributed across the southwest of Western Australia, growing exclusively in sandy soils. It is usually the dominant plant in scrubland or low woodland. It is pollinated by, and is a food source for, birds, mammals, and insects.
Banksia telmatiaea, commonly known as swamp fox banksia or rarely marsh banksia, is a shrub that grows in marshes and swamps along the lower west coast of Australia. It grows as an upright bush up to 2 metres tall, with narrow leaves and a pale brown flower spike, which can produce profuse quantities of nectar. First collected in the 1840s, it was not published as a separate species until 1981; as with several other similar species it was previously included in B. sphaerocarpa.
Banksia violacea, commonly known as violet banksia, is a species of shrub or tree in the plant genus Banksia. It generally grows as a small shrub to 1.5 m (5 ft) high with fine narrow leaves, and is best known for its unusually coloured dark purple-violet inflorescences. The colour of the inflorescences, short leaves, and flattened follicles which are sticky when young, help identify this species from others in the field. It is found in low shrubland in southern regions of Western Australia from Esperance in the east to Narrogin in the west, growing exclusively in sandy soils.
Banksia ser. Abietinae is a valid botanic name for a series of Banksia. First published by Carl Meissner in 1856, the name has had three circumscriptions.
Banksia micrantha is a species of small shrub that is endemic to the south-west of Western Australia. It is a spreading bush with sharply-pointed linear leaves, pale yellow flower spikes and up to twenty-five follicles surrounded by the remains of the flowers. It was first formally described by Alex George in 1981.
Kevin Thiele and Pauline Ladiges taxonomic arrangement of Banksia, published in 1996, was a novel taxonomic arrangement that was intended to align the taxonomy of Banksia more closely with the phylogeny that they had inferred from their cladistic analysis of the genus. It replaced Alex George's 1981 arrangement, but most aspects were not accepted by George, and it was soon replaced by a 1999 revision of George's arrangement. However some herbaria have continued to follow Thiele and Ladiges on some points.
Alex George's taxonomic arrangement of Banksia was the first modern-day arrangement for that genus. First published in 1981 in the classic monograph The genus Banksia L.f. (Proteaceae), it superseded the arrangement of George Bentham, which had stood for over a hundred years. It was overturned in 1996 by Kevin Thiele and Pauline Ladiges, but restored by George in 1999. A recent publication by Austin Mast and Kevin Thiele suggests that it will soon be overturned again.
Banksia spinulosa var. collina is a shrub that grows along the east coast of Australia, in Queensland and New South Wales. Commonly known as Hill Banksia or Golden Candlesticks, it is a taxonomic variety of B. spinulosa. It is a popular garden plant widely sold in nurseries.
Banksia subser. Leptophyllae is a valid botanic name for a subseries of Banksia. It was published by Kevin Thiele in 1996, but discarded by Alex George in 1999.
Banksia sphaerocarpa var. dolichostyla, commonly known as Ironcap Banksia, is a plant which is either considered a variety of Banksia sphaerocarpa, or as a species in its own right. It is native to the Southwest Botanical Province of Western Australia. Seeds do not require any treatment, and take around 33 days to germinate.
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