Banksia brownii
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Banksia brownii is a species of plant in the genus Banksia inthe silver tree family (Proteaceae). The natural occurrences of this endemic plant speciesin the southwest of Australiaare particularlythreatenedby pathogens that have been introduced. Like other Banksia species, Banksia brownii is alsocultivatedas a cut flower due to its attractive inflorescences, especially in Australian horticulture ; Compared to other Banksia species, however, it plays a rather subordinate role.
description
Appearance, bark and leaf
Banksia brownii usually grows as an upright shrub with heights between 1 and 3 meters, but occasionally also as a small tree up to 6 meters high or in higher, exposed locations as a low, widened shrub. The gray-brown bark is smooth, thin and covered with cork warts .
The dark green leaves are long and thin, between 3 and 10 centimeters long and 5 to 10 millimeters wide. On the underside they are provided with white hairs. The surface is hairless. At first glance, the leaf looks feathery, but it is very lobed. The incisions between the up to 70 lanceolate leaf lobes, which are curved towards the tip, end just before the midrib.
Inflorescence and flower
The terminal, upright, branched, piston-shaped inflorescence is approximately cylindrical with a height of 6 to 19 centimeters and a diameter of 8 to 10 centimeters. The inflorescence is metallic red-brown. Hundreds of densely packed single flowers stand in a spiral around the woody main axis. They are composed of four overgrown tepals that are cream-colored at the base and gray-brown at the end. The long, thin stylus is rusty bent down with a cream-colored top and light.
Fruit and seeds
The piston-shaped collecting bellows is composed of up to sixty individual bellows, but only a few are common. The individual follicles are lignified and have a diameter of about 5 centimeters. The withered flower parts make them appear woolly hairy. Each individual follicle contains only a single seed , which is unusual for a Banksia . These shiny black seeds are oval with a length of up to 20 millimeters and have brown, paper-like wings.
ecology
Plant populations close to the coast usually bloom for the first time in the age of five, whereas the population in the Stirling Range does not bloom until years later. Investigations at one location there showed that even in the eighth year only 15% of the plant specimens bloomed. The flowering time is variable. It starts in March and ends in August with a peak in June. Most of the flowers open during the day.
Like other Banksia species, Banksia brownii produces large quantities of nectar and thus serves as a source of food for numerous birds, insects and mammals. In addition to native and imported bees , honey-eaters such as the white-eyed honey-eater , the red-rag honey-eater or the colored-head honey-eater , mammals such as the Australian bush rat or the honeybutler also serve as pollinators .
Banksia brownii is basically self-compatible , although it has been observed that seeds from self-pollination are disadvantaged in the course of natural selection . Regardless of this, it was found that the species has one of the lowest crossing rates of all Banksia species. Possibly this is due to the small size of the populations, which hardly stimulates the visit of pollinators and thus reduces the probability of cross-pollination.
With less than 1% of the flowers, there is successful pollination and fertilization as well as the formation of the fruit. Over 50% of the inflorescences do not produce any fruit at all. The survival rate of the seeds themselves is also extremely low, more than half of the seeds of a plant fall victim to moths and weevils , which bore into the fruit, whose larvae eat the seeds and which pupate in the follicles. Grain eater such as cockatoos , which open the fruit to eat seeds and larvae, cause further losses .
The fruits stay on the mother plant for years. A small part of the follicles ripens and opens spontaneously, releasing the seeds. The majority of the bellows remain closed until the next bush fire, when the bellows then open. Although these bushfires destroy the mother plant, which is neither protected by a thick bark nor can it sprout again by lignotuber , they enable the stand to be regenerated by the sowing.
Since Banksia brownii does not release most of its seeds until after bushfires, these must be done at regular intervals to enable the stocks to produce and release sufficient quantities of seeds. The optimal interval is around 18 years. If the distances are reduced, the plants burn as immature plants or before they have formed sufficient quantities of seeds to regenerate the stand. On the other hand, if the fires are too far apart, the plants will die before their seeds are released.
Occurrence
Banksia brownii is endemic to southwest Western Australia between Albany and the Stirling Range . The area is the main distribution area of the genus with 19 Banksia species (including five other endemics). Banksia brownii grows in two geographically separate areas. In the southern area it is mostly found in forests dominated by Eucalyptus marginata with flat, nutrient-poor, white or gray sandy soils on laterite . In the northern subarea in the Stirling Range Mountains, Banksia brownii grows at altitudes between 500 and 1100 meters, in heathland on rocky mountain slopes and peaks and in ravines on slate . It is associated with other species of the genus Banksia and species of the genera Dryandra , Lambertia , Isopogon , Hakea , Adenanthos , Eucalyptus , Agonis , Kunzea and Beaufortia .
Only 17 locations are known of Banksia brownii , they comprise a total of about 12,000 individuals. Only five of the locations consist of more than 200 individuals and only two of more than 500. Half of the locations comprise fewer than 20 individuals.
The climate in this area is temperate. The temperatures fluctuate between 4 and 30 ° C. The annual precipitation is 800 millimeters.
Endangerment and Status
With the exception of two locations, all populations of Banksia brownii suffer from death caused by the plant-damaging organism Phytophthora cinnamomi , which also threatens numerous other south-west Australian plant species and leads to root rot. The two previously uninfected locations are also in endangered areas and are therefore also considered threatened.
Forest death is combated by restricting access to the sites and by spreading phosphite over a wide area , which strengthens the plants' resistance to infections and is also effective as an agent against Phytophthora . Spraying from the air can also harm the plants, as the uptake by the leaves impairs the growth of roots and shoots, so the product can only be used to a limited extent. These control measures are accompanied by the collection and cold storage of seeds for later reforestation.
In addition to dying by Phytophthora cinnamomi , the species is also endangered by habitat loss due to clearing for settlement purposes , changes in the interval between the necessary bushfires and the collection of inflorescences for commercial purposes. The increasing fragmentation of the sites also threatens the species, as it can indirectly lead to genetic bottlenecks and reduced vitality .
Banksia brownii has been listed in Australia as Endangered since 1999 and as Rare in Western Australia's Wildlife Conservation Act . Based on these ratings, some threats (such as deforestation and commercial collection) have been reduced. The northern stocks of the Stirling Range are also protected, as the area is classified as a national park ( Stirling Range National Park ). Regardless of this, due to the death of the species and a calculated decline in populations of 80% in three generations, an increase in the endangerment level to Critically Endangered was called for.
It is assumed that without protective measures , Banksia brownii will be extinct within 10 years. The complete disappearance of the species can have unforeseen and possibly far-reaching consequences for the functioning of the ecosystem by changing the vegetation composition, in which Banksia brownii is an essential element (not only a tragedy in itself but may have unforeseen, and potentially disastrous, consequences for the functioning of the vegetation communities of which feather-leaved banksia is an integral part.)
Systematics
Two genetically different types of Banksia brownii are currently reported: a mountain form, which is characterized by a shrubby habit , short, thin and hard leaves and a crowded inflorescence and the "Millbrook Road form", which grows as a tree and is longer, wider and has soft leaves. These forms do not currently have a systematic rank. However, genetic studies are planned to determine whether subspecies status is justified for both forms. Among lovers there are also reports of a cross between the two types, but whose offspring are not fertile. This can be taken as an indication of a possible species rank of both forms.
Banksia brownii is currently placed in the subgenus Banksia , section Oncostylis , series Spicigerae (the latter because of the cylindrical inflorescences). The Spicigerae are understood as one of the oldest ranks of the Banksien, it includes both Western and Eastern Australian species, which suggests that it goes back to the time before the formation of the Nullarbor Desert . Its closest relative is Banksia occidentalis , which differs from Banksia brownii by its smaller, dark red flowers and only weakly toothed leaves .
Phylogenetic studies based on both morphological and molecular genetic features confirmed the classification in the Oncostylis section and the close relationship with Banksia occidentalis .
Botanical history
Banksia brownii was first collected in 1829 near King George Sound by William Baxter and first named by him, the specific epithet honors the British botanist Robert Brown . The first formal description comes from this very same and appeared in 1830 in the appendix to Prodromus Florae Novae Hollandiae . Brown placed Banksia brownii in the subgenus Banksia verae , the "real Banksien", because its inflorescence is a typical Banksia inflorescence. The Banksia verae were renamed Eubanksia by Stephan Endlicher in 1847 and downgraded to a section by Carl Meissner in 1856 . Meissner also divided the section into three rows and placed Banksia brownii among the Dryandroideae . George Bentham rejected Meissner's series in his work Flora Australiensis in 1870 and summarized the species with hook-shaped styluses in a section which he named Oncostylis . This system existed for over a hundred years until the publication of Alex George's monograph The Genus Banksia Lf (Proteaceae) in 1981.
use
Thanks to the large, metallic-red inflorescences and the extremely soft and appealing feather-like leaves, Banksia brownii is just as suitable as other Banksia species as a horticultural crop. However, in terms of its importance as a cut flower in Australian horticulture, it is clearly behind other cultivated Banksia species such as B. Banksia coccinea , Banksia prionotes or Banksia burdetti . Banksia brownii is a correspondingly widespread crop in regions that are not affected by the Phytophthora death. They prefer a protected, well-drained location that is kept moist in summer. Banksia brownii is fast-growing, but only flowers after a few years. Once established, Banksia brownii is frost hardy and can be pruned moderately. The flowers are particularly attractive as late buds, but as they open they lose their color.
The main obstacle to cultivation is the aforementioned susceptibility of Banksia brownii to the pathogen Phytophthora cinnamomi , which is also often found in gardens. A refinement on rhizomes of Banksia integrifolia other hand reduces susceptibility while allowing the planting on land which the profile of Banksia brownii differ.
swell
Individual evidence
- ↑ a b c d e f Alex George: The Genus Banksia Lf (Proteaceae) . In: Nuytsia . 3, No. 3, 1981, pp. 239-473
- ↑ a b c d e Alex S. George: The Banksia Book. , 1984, ISBN 0-86417-006-8
- ↑ a b c d Alex S. George: Banksia. , in: Wilson, Annette (Ed.), Flora of Australia, Vol. 17B: Proteaceae 3: Hakea to Dryandra , pp. 175-251, CSIRO Publishing / Australian Biological Resources Study, 1999, ISBN 0-643-06454-0
- ↑ a b c d e f Denise A. Day, Brian G. Collins, Rosemarie G. Rees: Reproductive biology of the rare and endangered Banksia brownii Baxter ex R. Br. (Proteaceae) . In: Australian Journal of Ecology , 22, 1997, pp. 307-315.
- ↑ a b c d e f g h i Anne Cochrane, Sarah Barrett, Sandra Gilfillan: The feather-leaved banksia. , In: Landscope , 20, No. 3, 2005, pp. 22-28. ISSN 0815-4465
- ↑ JF Sampson, DJ Coates, SJ van Leeuwen: Mating system variation in animal-pollinated rare and endangered plant populations in Western Australia , in: SD Hopper, M. Harvey, J. Chappill, AS George (eds.) Gondwanan Heritage: Past , Present and Future of the Western Australian Biota , pp. 292-298, ISBN 0-949324-66-3
- ↑ JF Sampson, BG Collins, DJ Coates: Mixed Mating in Banksia brownii Baxter ex R. Br. (Proteaceae) , in: Australian Journal of Botany. 42, 1994, pp. 103-111
- ↑ Ross L. Goldingay, Susan M. Carthew: Breeding and Mating Systems of Australian Proteaceae , in Australian Journal of Botany. 46, No. 4, 1998, pp. 421-437
- ↑ BG Collins, S. McDavitt, JF Sampson: Flowering phenology and fecundity of Banksia brownii Baxter ex R.Br. (Proteaceae) , in: SD Hopper, M. Harvey, J. Chappill, AS George (Eds.) Gondwanan Heritage: Past, Present and Future of the Western Australian Biota , pp. 292–298, ISBN 0-949324-66- 3
- ↑ a b c Banksia brownii: Brown's Banksia, Feather-leaved Banksia , in: Species Profile and Threats Database. Department of the Environment and Heritage, Online, accessed July 10, 2006
- ↑ Byron B. Lamont, SW Connell: Biogeography of Banksia in southwestern Australia , 1996, in: Journal of Biogeography 23 (3): pp. 295-309, doi : 10.1046 / j.1365-2699.1996.00027.x .
- ^ A b Anne Taylor, Stephen D. Hopper: The Banksia Atlas (Australian Flora and Fauna Series Number 8) , 1988, ISBN 0-644-07124-9
- ↑ a b J. H. Leigh, JD Briggs (ed.): Threatened Australian Plants: Overview and Case Studies , ISBN 0-642-14203-3
- ^ SR Barrett, BL Shearer, GE St G. Hardy: The efficacy of phosphite applied after inoculation on the colonization of Banksia brownii stems by Phytophthora cinnamomi in: Australian Plant Pathology 32: 1-7, 2003
- ↑ SR Barrett, BL Shearer, GE St J. Hardy: Root and shoot development in Corymbia calophylla and Banksia brownii after the application of the fungicide phosphite , in: Australian Journal of Botany. 50, No. 2, 2002
- ^ A b Brown, Andrew, Carolyn Thomson-Dans, Neville Marchant (Eds.): Western Australia's Threatened Flora . Department of Environment and Conservation, Conservation and Land Management, Como, Western Australia 1998, ISBN 0-7309-6875-8 .
- ↑ Wildlife Conservation (Rare Flora) Notice 2006 , in: Government Gazette, WA, pp. 2169–2174, 2006
- ↑ a b Greg Keighery: Endangered! Brown's Banksia (Banksia brownii) , in: Landscope. 3, No. 4, 1988, p. 54
- ↑ a b Liber, Cas (ed.): Threatened Banksia's # 2: Banksia brownii , in: Banksia Study Group Newsletter. 5, No. 1, 2003, pp. 1-2, PDF Online
- ↑ Kevin Thiele, Pauline Y. Ladiges: A Cladistic Analysis of Banksia (Proteaceae) , in: Australian Systematic Botany. 9, No. 5, 1996, pp. 661-733
- ↑ Austin R. Mast, Eric H. Jones, Shawn P. Havery: An Assessment of Old and New DNA sequence evidence for the Paraphyly of Banksia with respect to Dryandra (Proteaceae) , in: Australian Systematic Botany. 18, No. 1, 2005, pp. 75-88. ISSN 1030-1887
- ^ Arthur D. Chapman: Banksia integrifolia Lf , Canberra: Australian Government Publishing Service , 1991, online
- ↑ Carl Meissner: Proteaceae , in: AP de Candolle (ed.): Prodromus systematis naturalis regni vegetabilis, pars decima quarta , Paris: Sumptibus Victoris Masson 1856, Online ( Memento des Originals from September 27, 2007 in the Internet Archive ) Info: Der Archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ George Bentham: Banksia. , Pp. 541-562, London: L. Reeve & Co., 1870
- ↑ Archive link ( Memento of the original dated December 30, 2006 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Banksias cutflowers
- ↑ Iain Dawson: Grafting Australian Native Plants , 1996, Online
Web links
- Detailed information on the type, their location and threat (English)
- Entry in the Flora of Western Australia (English)
- Entry in the Flora of Australia (English)
