Taxonomy of Banksia integrifolia

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The taxonomy of Banksia integrifolia has a long and complex history, the result of confusion caused by the species' great variability, similarities with some closely related species, the existence of hybrids between B. integrifolia and related species, and early attempts to classify the species based on dried specimen material alone. It is now largely settled, with the species now placed in Banksia subg. Banksia sect. Banksia ser. Salicinae, and divided into three subspecies: B. i. subsp. compar, B. i. subsp. integrifolia, and B. i. subsp. monticola. The only remaining bones of contention are the relationships between B. integrifolia and several closely related species within series Salicinae.

Contents 1 Background 2 Discovery 3 Taxonomic history 4 Placement within Banksia 5 Subspecies and hybrids 6 References 7 External links

[edit] Background

Main article: Banksia integrifolia

Commonly known as Coast Banksia, B. integrifolia is one of the best known and most widely distributed species of Banksia. Widely distributed along the east coast of Australia from Victoria to Central Queensland, it is highly variable in form, but is most often encountered as a tree up to 25 metres (75 ft) in height. Hardy and versatile, it is a popular garden plant.

[edit] Discovery

The first botanical collection of B. integrifolia was made by Sir Joseph Banks and Dr Daniel Solander, naturalists on the Endeavour during Lieutenant (later Captain) James Cook's first voyage to the Pacific Ocean. Cook landed on Australian soil for the first time on 29 April 1770, at a place that he later named Botany Bay in recognition of "the great quantity of plants Mr Banks and Dr Solander found in this place".^[1] Over the next seven weeks, Banks and Solander collected thousands of plant specimens, including the first specimens of a new genus that would later be named Banksia in Banks' honour.

Every specimen collected during the Endeavour voyage was sketched by Banks' botanical illustrator Sydney Parkinson. On the Endeavour's return to England in July 1771, Banks' specimens became part of his London herbarium, and artists were employed to paint watercolours from Parkinson's sketches. Banks had plans to publish his entire collection as "Banks' Florilegium", but for various reasons the project was never completed, and it would be ten years before any of the Banksia species were formally published.^[2]

[edit] Taxonomic history

The genus Banksia was eventually described by Carolus Linnaeus the Younger in his April 1782 publication Supplementum Plantarum. Linnaeus described four Banksia species, distinguishing them by their leaf shape, and naming them accordingly. Thus the species with entire leaf margins was given the specific name integrifolia, from the Latin integer, meaning "entire", and folium, meaning "leaf".^[3] The full name of the species is therefore "Banksia integrifolia L.f."^[4]

Then followed two centuries of uncertainty as to the taxonomic limits of B. integrifolia. The first sign of confusion was in 1788, when Joseph Gaertner published B. spicata.^[5] Gaertner did not specify his type material for the taxon, but contemporary material labelled as such clearly belongs to what is now known as B. i. subsp. integrifolia.^[6] In 1810, Robert Brown relegated the name to synonymy with B. integrifolia,^[7] and it remained so until 1981 when Alex George refined it to a synonym of B. i. var. integrifolia.^[6]

In 1800, Antonio José Cavanilles published a number of new Banksia species, based on specimens collected at Port Jackson, New South Wales in 1797 by Luis Née, botanist to the Alejandro Malaspina expedition. These included B. oblongifolia, B. oleifolia and B. glauca. The last two of these were declared synonyms of B. integrifolia by Robert Brown in 1810,^[7] and refined to synonyms of B. i. subsp. integrifolia by George in 1999.^[8] The first was ascribed to B. i. var. oblongifolia by Karel Domin in 1930, but this was overturned by George in 1981,^[6] and B. oblongifolia remains a current species name.^[4]

In 1810, Robert Brown described 31 known species of Banksia in his Prodromus Florae Novae Hollandiae et Insularae Van-Diemen. He split the genus into two subgenera, placing B. integrifolia in subgenus Banksia verae, the "True Banksias".^[7] New species described by Brown included B. compar, which is now considered a subspecies of B. integrifolia,^[4] and B. paludosa, a close relative of B. integrifolia which was for a time considered a variety of it.^[9]

By the time Carl Meissner published his 1856 classification of the Proteaceae, there were 58 described Banksia species. Meissner divided Brown's Banksia verae, which had been renamed Eubanksia by Stephan Endlicher in 1847,^[6] into four series based on leaf properties. He placed B. integrifolia in series Salicinae, and further divided it into three varieties: B. i. var. minor for specimens with small, entire leaves; B. i. var. major for specimens with larger, somewhat dentate leaves; and B. integrifola var dentata for specimens with very large dentate leaves.^[10] However, the second of these varieties were based upon a specimen of B. integrifolia with juvenile leaves, and the last was B. robur. All three were overturned by George in 1981.^[6]

In 1870, George Bentham published a thorough revision of the Banksia in his landmark publication Flora Australiensis. Meissner's four series were replaced by four sections based on leaf, style and pollen-presenter characters. B. integrifolia was placed in section Eubanksia along with B. marginata and B. dentata. The number of recognised Banksia species was reduced from 58 to 46, with B. compar declared a synonym of B. integrifolia, and B. paludosa relegated to a variety of B. integrifolia.^[9] The former taxon is now a considered a subspecies of B. integrifolia, but the B. paludosa has since been reinstated as a species and remains a current species name.^[4]

A major disruption to Banksia nomenclature occurred in 1891, when Otto Kuntze attempted to have the Banksia genus renamed Sirmuellera, on the grounds that Banksia J.R.Forst & G.Forst (referring to the genus now known as Pimelia was published before Banksia L.f., and therefore took precedence. Kuntze published new names for each of the Banksia species, renaming B. integrifolia to Sirmuellera integrifolia (L.f.) Kuntze.^[11] Kuntze's challenge failed, as did a similar challenge by James Britten in 1905. Britten proposed the generic name Isostylis, republishing B. integrifolia as Isostylis integrifolia (L.f.) A.T.Lee. This challenge also failed, and in 1940 Banksia L.f. was formally conserved against future challenges.^[6]

In 1913, Frederick Bailey promoted Brown's B. compar, which had been declared a synonym of B. integrifolia by Bentham in 1870, to variety rank as B. i. var. compar. This would be the first infraspecific taxon of B. integrifolia to achieve widespread acceptance.^[4] The variety was promoted to subspecies rank by Kevin Thiele in 1994,^[12] and B. i. subsp. compar remains a current taxon to date.^[4] Under modern botanical nomenclature rules, the publication of subspecies B. i. subsp. compar automatically published the autonym B. i. subsp. integrifolia, to encompass the type material.

The current taxonomic treatment of Banksia first appeared in 1981 in Alex George's classic 1981 monograph The Genus Banksia L.f. (Proteaceae). In addition to revising the existing nomenclature, George published a number of new species and subspecies. Among them was a new variety of B. integrifolia, B. i. var. aquilonia.^[6] This was promoted to subspecific rank by Thiele in 1994,^[12] and in 1996 George promoted it to specific rank as Banksia aquilonia.^[13]

A third subspecific taxon of B. integrifolia has its roots in Gwen Harden's 1991 publication Flora of New South Wales. Harden recognised a new subspecies of B. integrifolia, but did not give it a name, referring to it only as "B. i. subsp. A".^[4] In 1994, Thiele confirmed the subspecific rank of this taxon, naming it B. i. subsp. monticola.^[12]

[edit] Placement within Banksia

The currently accepted taxonomic arrangement for the Banksia genus is based on Alex George's 1999 monograph for the Flora of Australia book series.^[8] In this arrangement, B. integrifolia is placed in Banksia subg. Banksia, because its inflorescences take the form of Banksia's characteristic flower spikes; Banksia sect. Banksia because of its straight styles; and Banksia ser. Salicinae because of its inflorescences are cylindrical.

Salicinae is considered a well-defined series, and subsequent research supports George's placement of B. integrifolia within it. However, relationships within Salicinae are not yet settled. In 1996, Kevin Thiele and Pauline Ladiges divided the series into two subseries: Banksia subser. Integrifoliae and Banksia subser. Acclives.^[14] The seven members of subseries Integrifoliae all appear to be closely related, and natural hybrids have been recorded between members where they co-occur. Molecular studies by Austin Mast also support this grouping.^[15] However, George did not maintain these subseries in his 1999 monograph, arguing that there was insufficient evidence for the division, and that "B. dentata is clearly allied to B. integrifolia, not to the very distinctive B. robur".^[8]

B. integrifolia's placement within Banksia may be summarised as follows:

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

(Subseries Acclives)

B. oblongifolia - B. plagiocarpa - B. robur - B. dentata

(Subseries Integrifoliae)

B. marginata - B. conferta - B. paludosa - B. canei - B. saxicola - B. integrifolia - B. aquilonia

[edit] Subspecies and hybrids

B. integrifolia is a highly variable species. Some of this variation can be attributed to environmental factors, but much appears to be genetic: George writes that it "gives the impression that it is actively speciating to fill the many ecological niches through its range".^[6] Three subspecies are currently recognised: B. i. subsp. integrifolia, B. i. subsp. compar, and B. i. subsp. monticola.

Hybrids have been reported between B. integrifolia and other members of series Salicinae, specifically B. paludosa^[16][17][18] and B. marginata,^[19][4] although no hybrid names have been formally published to date.

[edit] References

[edit] External links

• Banksia integrifolia at Flora of Australia Online, Department of the Environment and Heritage, Australia.
• Banksia integrifolia at the Australian Plant Names Index.