Banksia telmatiaea

Australian shrub that grows in marshes and swamps

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 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 (fox banksia). The shrub grows amongst scrubland in seasonally wet lowland areas of the coastal sandplain between Badgingarra and Serpentine in Western Australia. A little studied species, not much is known of its ecology or conservation biology. Reports suggest that a variety of birds and small mammals pollinate it. Like many members of the series Abietinae, it has not been considered to have much horticultural potential and is rarely cultivated.

B. telmatiaea grows as an upright bush up to high. It has hairy stems and branchlets, and straight, narrow leaves from long and about a wide. The leaves have a green upper surface and white hairy undersurface. The new growth is pale brown, later turning green. each of which consists of a tubular perianth made up of four fused tepals, and one long wiry style. The styles are hooked rather than straight, and are initially trapped inside the upper perianth parts, but break free at anthesis. The species generally flowers from April to August, although flowers have been observed as late as November. It was eventually published by Alex George in his 1981 monograph The genus Banksia L. f. (Proteaceae), based on a specimen collected by him on the Brand Highway about north of Regans Ford on 14 May 1969, and labelled "A. S. George 9309". He found it most closely resembled B. leptophylla, but regarded its preference for swampy rather than sandy soils and winter flowering as worthy of warranting species status. George gave it the specific name telmatiaea from the Greek stem telmat /τελματ ("the mud of a pond"), in reference to its swampy habitat. Common names for B. telmatiaea include swamp fox banksia and marsh banksia.

George placed B. telmatiaea in subgenus Banksia because its inflorescence is a typical Banksia flower spike, section Oncostylis because it has hooked styles, and series Abietinae because its inflorescence is roughly spherical. He considered its closest relative to be B. leptophylla (Slender leaved Banksia), which differs from B. telmatiaea in having longer leaves and larger flowers; yet in his arrangement he placed it between B. scabrella (Burma Road Banksia) and B. laricina (Rose fruited Banksia). This clade became the basis of B. subser. Leptophyllae, which Thiele defined as containing those species with "indurated and spinescent common bracts on the infructescence axes, and densely arachnose seedling stems." In accordance with their cladogram, their arrangement placed B. telmatiaea next to B. scabrella. 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. telmatiaea is placed in B. subg. Spathulatae.

B. telmatiaea grows only in the Swan Coastal Plain, Geraldton Sandplains and Jarrah Forest biogeographic regions, inland from the coast but never east of the Darling Scarp. It occurs from Hill River near Badgingarra in the north, to Serpentine in the south. Most populations occur north of Moore River or south of Cannington, there being only a few scattered populations in between. The species favours lowland areas that are seasonally wet but never inundated, such as the margins of swamps and marshes. For example, in the Yule Brook Botany Reserve, where parallel sand ridges cross a clay flat, B. telmatiaea occurs neither in the lowest parts of the flat, where seasonal inundation occurs; nor on the tops of the ridges, where the drainage is good; but it is one of the most abundant plants of intermediate habitats, on ridge slopes and in higher areas of the clay flat. Favoured soils are deep grey sandy loams or shallower sand overlying claypan. Associated vegetation is typically scrubland or shrubland, although moisture loving trees such as B. littoralis (swamp banksia) or Melaleuca preissiana (moonah) may also be present, sometimes in sufficient numbers to form a low open woodland.

Like most other Proteaceae, B. telmatiaea has 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. Unlike many Banksia species, B. telmatiaea lacks a lignotuber, so plants are killed by bushfire. It is adapted to release its aerial seed bank following a bushfire, and so regenerates rapidly. This behaviour, known as serotiny, makes B. telmatiaea dependent upon a suitable fire regime for successful regeneration; indeed, excessive fire frequency may be one reason why B. telmatiaea does not occur further south, despite suitable habitat throughout southwest Australia. Unlike most serotinous Banksia species, the seeds of B. telmatiaea are not released immediately after the passage of a bushfire. The follicles open straight away, but at first the seeds are blocked from falling out by the winged seed separator. If moistened, these wings close up, and as they dry they open out again, levering the seeds out of position, making it possible for them to fall. This adaptation ensures that seeds are released only after the first rains following a bushfire. Four species of bird have been observed visiting the flowers of B. telmatiaea: the red wattlebird (Anthochaera carunculata), and studies of other Banksia species have consistently demonstrated their involvement. Moreover, a number of characteristics of the B. telmatiaea spike are purported to be adaptations to pollination by nocturnal mammals: the strong, musky odour, In the case of B. telmatiaea, it eventually becomes "an almost black, gelatinous lump adhering to the base of the flowers". Further investigations 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". albeit dominated by sucrose. in fact it is so reliably susceptible that it is used as an indicator species for the presence of the disease. An assessment of the potential impact of climate change on this species found that severe change is likely to lead to extinction; but under less severe change scenarios the distribution may actually grow, depending on how effectively it can migrate into newly habitable areas. In 1987, George applied the Rare or Threatened Australian Plants (ROTAP) criteria to the species, determining it to have a conservation status of "3R": a rare species found only in small populations, but not considered endangered or vulnerable.

B. telmatiaea is rarely cultivated. It grows fairly quickly, but tends to become untidy as it ages. The flower spikes, though attractive, occur within the bush where they are usually obscured by foliage. In its natural habitat it flowers prolifically over several months, but according to George it may be reluctant to flower in cultivation. It tolerates light pruning not below the green foliage. George recommends a sunny position in poorly drained soil, preferably with moisture in winter.