Dallachy's Banksia | |
---|---|
Rare (NCA) | |
Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Eudicots |
Order: | Proteales |
Family: | Proteaceae |
Genus: | Banksia |
Species: | B. plagiocarpa |
Binomial name | |
Banksia plagiocarpa | |
Banksia plagiocarpa, commonly known as Dallachy's blue banksia, blue banksia or Hichinbrook banksia, [2] is a species of shrub or tree in the plant genus Banksia . It occurs only on Hinchinbrook Island, Queensland and the immediately adjacent mainland. First collected in 1867, Banksia plagiocarpa was not described until 1981, when Alex George named it in his monograph of the genus Banksia . Genetic studies show it to be related to Banksia aquilonia , Banksia oblongifolia and Banksia robur .
Banksia plagiocarpa grows as a shrub to 5 m (16 ft) high with greyish broken bark. The new growth is covered in red velvety fur, which falls off after two or three years. The long narrow lanceolate (spear-shaped) to obovate leaves are arranged alternately along the stems. Measuring 8 to 20 cm (3.1 to 7.9 in) long by 0.6–1.7 cm (0.24–0.67 in) wide, they have recurved margins lined with blunt serrations. Appearing from February to July, the flower spikes, known as inflorescences, are 7 to 14 cm (2.8 to 5.5 in) high and 5–6 cm (2.0–2.4 in) in diameter at anthesis. Arising terminally or from one- to two-year-old branches, they are often surrounded at the base by a whorl of small branchlets. [3] [4]
Banksia plagiocarpa was first collected on 20 December 1867 and 21 February 1868 by John Dallachy (a collector for Victorian Government Botanist Ferdinand von Mueller) from Bishops Peak in the Cardwell Ranges, the specimens lodged at Kew and Melbourne Herbariums. However, it was not collected again until 28 December 1979 by Fred Hockings from Hinchinbrook Island. Both Dallachy and Hockings remarked on the unusual flower colour, the former describing it as "pale blue", the latter "greenish-purple". It was finally described in Alex George's 1981 revision of the genus. The species name is derived from the Ancient Greek words plagios "sloping" or "oblique", and carpos "fruit", and refers to the upturned wedge-shaped follicles. [3] Common names include Dallachy's banksia and blue banksia. [5]
The current taxonomic arrangement of the genus Banksia is based on botanist Alex George's 1999 monograph for the Flora of Australia book series. In this arrangement, B. plagiocarpa is placed in Banksia subgenus Banksia , because its inflorescences take the form of Banksia's characteristic flower spikes, section Banksia because of its straight styles, and series Salicinae because its inflorescences are cylindrical. [4] George held it to be most closely related to Banksia oblongifolia , which he noted often had flower spikes that were tinged blue-grey in bud, and also have affinities to the co-occurring species Banksia aquilonia [3] In a morphological cladistic analysis published in 1994, Kevin Thiele placed it in the newly described subseries Acclives, within the series Salicinae. It appeared to be the earliest offshoot of the group, which also consisted of B. oblongifolia, B. dentata and B. robur . [6] However, this subgrouping of the Salicinae was not supported by George. [4]
B. plagiocarpa's placement within Banksia may be summarised as follows:
Since 1998, American botanist Austin Mast and co-authors have been publishing results of ongoing cladistic analyses of DNA sequence data for Banksia and Dryandra . Their analyses suggest a phylogeny that differs greatly from George's taxonomic arrangement, and had some similarities to Thiele and Ladiges', thus Banksia plagiocarpa grouped in a clade with B. aquilonia, B. oblongifolia and B. robur. [7] [8] [9] A 2013 molecular study by Marcel Cardillo and colleagues using chloroplast DNA and combining it with earlier results reaffirmed B. plagiocarpa as an offshoot of a lineage that gave rise to B. robur, B. oblongifolia and B. aquilonia. [10]
Early 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, then B. plagiocarpa is placed in B. subg. Spathulatae. [11]
The range of Banksia plagiocarpa is limited to Hinchinbrook Island, where it is found on the top and slopes of Mount Bowen and Nina Peak, and the adjacent mainland on the Queensland north coast, where it is found on the summit and slopes of Bishops Peak. [12] The annual rainfall is 2,400 mm (94 in). [5] The habitat is either open woodland or grassland, and it can be the dominant shrub. The altitude it grows at on Hinchinbrook is between 200 and 720 m (660 and 2,360 ft), on gravelly, rocky or clay soils, and in association with such plants as tantoon ( Leptospermum polygalifolium ) and she-oaks ( Casuarina ), as well as Banksia aquilonia at lower altitudes below 400 m (1,300 ft). On the mainland, it is found in a more sandy soil, often near water. [12]
This banksia is listed as "vulnerable" under the Queensland Government Nature Conservation Act 1992 . [2]
Banksia plagiocarpa adapts readily to cultivation, and grows well with good drainage and a sunny aspect. It has been grown successfully in cooler climates such as the Australian National Botanic Gardens in Canberra and the Royal Botanic Gardens, Cranbourne. It flowers in four to five years from seed. Its horticultural features are its gunmetal grey-blue buds and red new growth. It has also been grown for the cut flower industry. [5]
Banksia subg. Isostylis is a subgenus of Banksia. It contains three closely related species, all of which occur only in Southwest Western Australia. Members of subgenus Isostylis have dome-shaped flower heads that are superficially similar to those of B. ser. Dryandra, but structurally more like reduced versions of the "flower spikes" characteristic of most other Banksia taxa.
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 canei, commonly known as the mountain banksia, is a species of shrub that is endemic to southeastern Australia. It is generally encountered as a many-branched shrub that grows up to 3 m (10 ft) high, with narrow leaves and the yellow inflorescences appearing from late summer to early winter. The old flowers fall off the spikes and up to 150 finely furred follicles develop, which remain closed until burnt in a bushfire. Each follicle bears two winged seeds. Response to fire is poorly known, although it is thought to regenerate by seed. Birds such as the yellow-tufted honeyeater and various insects forage among the flower spikes. It is frost tolerant in cultivation, but copes less well with aridity or humidity and is often short-lived in gardens. One cultivar, Banksia 'Celia Rosser', was registered in 1978, but has subsequently vanished.
Banksia oblongifolia, commonly known as the fern-leaved, dwarf or rusty banksia, is a species in the plant genus Banksia. Found along the eastern coast of Australia from Wollongong, New South Wales in the south to Rockhampton, Queensland in the north, it generally grows in sandy soils in heath, open forest or swamp margins and wet areas. A many-stemmed shrub up to 3 m (9.8 ft) high, it has leathery serrated leaves and rusty-coloured new growth. The yellow flower spikes, known as inflorescences, most commonly appear in autumn and early winter. Up to 80 follicles, or seed pods, develop on the spikes after flowering. Banksia oblongifolia resprouts from its woody lignotuber after bushfires, and the seed pods open and release seed when burnt, the seed germinating and growing on burnt ground. Some plants grow between fires from seed shed spontaneously.
Banksia paludosa, commonly known as the marsh or swamp banksia, is a species of shrub in the plant genus Banksia. It is native to New South Wales, Australia, where it is found between Sydney and Batemans Bay, with an isolated population further south around Eden. There are two recognised subspecies, the nominate of which is a spreading shrub to 1.5 m (4.9 ft) in height, and subsp. astrolux is a taller shrub to 5 m (16 ft) high found only in Nattai National Park.
Banksia saxicola, the rock banksia or Grampians banksia, is a species of tree or shrub in the plant genus Banksia. It occurs in Victoria in two distinct populations, one in The Grampians and the other on Wilsons Promontory. Formerly considered to be a form of B. integrifolia, it was described as a distinct species by Alex George in 1981. It is most closely related to Banksia marginata.
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 aquilonia, commonly known as the northern banksia and jingana, is a tree in the family Proteaceae and is endemic to north Queensland on Australia's northeastern coastline. With an average height of 8 m (26 ft), it has narrow glossy green leaves up to 20 cm (7.9 in) long and 6 to 10 cm high pale yellow flower spikes, known as inflorescences, appearing in autumn. As the spikes age, their flowers fall off and they develop up to 50 follicles, each of which contains two seeds.
Banksia ser. Salicinae is a valid botanic name for a series of Banksia. First published by Carl Meissner in 1856, the name has had three circumscriptions.
The taxonomy of Banksia integrifolia has a long and complex history, the result of confusion caused by the species' great variability, and similarities with some closely related species. The existence of hybrids between B. integrifolia and related species as well as early attempts to classify the species based on dried specimen material have also contributed to the confusion.
Banksia ser. Quercinae is a valid botanic name for a series of Banksia. First published by Carl Meissner in 1856, the name has had three circumscriptions.
Banksia ser. Cyrtostylis is a taxonomic series within the plant genus Banksia. First published at sectional rank by George Bentham in 1870, it was demoted to a series by Alex George in 1981. The name has had three circumscriptions.
Banksia ser. Crocinae is a taxonomic series in the genus Banksia. The series was first published by Alex George in 1981, but discarded by Kevin Thiele and Pauline Ladiges in 1996, and finally reinstated by George in 1999. Recent cladistic analyses suggest that it is monophyletic or nearly so.
Banksia ser. Banksia is a valid botanic name for a series of Banksia. As an autonym, it necessarily contains the type species of Banksia, B. serrata. Within this constraint, however, there have been various circumscriptions.
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 subser. Longistyles 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 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 ser. Ochraceae is a valid botanic name for a taxonomic series within the plant genus Banksia. It was published by Kevin Thiele in 1996, but discarded by Alex George in 1999.
Banksia subser. Cratistylis is a valid botanic name for a subseries of Banksia. It was first published by Kevin Thiele in 1996 but discarded by Alex George in 1999.