Banksia grossa | |
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B. grossa north of Badgingarra | |
Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Eudicots |
Order: | Proteales |
Family: | Proteaceae |
Genus: | Banksia |
Species: | B. grossa |
Binomial name | |
Banksia grossa | |
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.
Found in sand or sand over laterite among heath between Eneabba and Badgingarra in Western Australia, the species grows as a many-stemmed shrub to 1 m (3.3 ft) high with narrow leaves and oval brownish flower spikes up to 10 cm (4 in) high, composed of hundreds of individual flowers. Flowering occurs throughout the cooler months of March to September. Flower spikes develop woody follicles which bear the seeds. After bushfire, Banksia grossa regenerates from its woody lignotuber; bushfires also stimulate the release of seeds, which germinate after disturbance. Visitors to (and likely pollinators of) inflorescences include insects and a nocturnal mammal, the white-tailed dunnart.
Banksia grossa grows as a bushy shrub, generally 0.7 to 1 m (28 to 39 in) high, [2] or occasionally up to 1.5 m (4.9 ft) high. [3] Its many stems rise from a woody lignotuber. [2] Young stems have a coating of woolly hairs, while older stems are covered in flaky pale brown bark. Borne on 3 to 5 mm long petioles, the somewhat fleshy leaves are needle-like. Although they are between 4 and 12 cm (1.5 and 4.5 in) long and only 2 to 3 mm wide, they are still thicker than those of other members of the series Abietinae . The margins of the leaves are straight with no teeth and rolled over, and the upper surfaces are sparsely hairy when young, but later hairless. [4] New growth occurs in the spring and early summer. [3]
Flowers occur in a typical Banksia flower spike: an inflorescence made up of hundreds of small individual flowers, or florets, densely packed around (and completely obscuring) a woody cylindrical axis. In B. grossa, this axis is 5 to 7 cm (2 to 3 in) high with a diameter of 0.7–0.9 cm (0.28–0.35 in). From this, the florets radiate out laterally, giving the inflorescence a diameter of 8 or 9 cm (3 or 3.5 in). [2] Flowers are rusty brown to golden brown, and consist of a hairy 3.4–4.5 cm (1.3–1.8 in) long tubular perianth which opens at maturity (anthesis) to release the dark red to purple style. [4] 3.8–4.8 cm (1.5–1.9 in) long, the style extends past the perianth and is curved at the tip. The flower spikes arise from short thick branchlets running off larger stems, though some flower spikes are terminal (located at the ends of branches and more prominently displayed in the foliage). [2]
Flowering occurs between March and September, [5] though early flowering in December has been recorded. [3] It takes five to eight weeks for a flower to develop from bud to the end of flowering. About three weeks before the flowers open, they develop a strong musky smell. The opening of flowers occurs sequentially, starting at the bottom of the inflorescence and sweeping through to the top over a period of around two weeks. At anthesis, the flowers produce copious quantities of nectar; indeed, some flowers produce so much that it drips to the ground. [5] After flowering, the old florets wither and curl against the spike, giving it a hairy appearance. Now known as an infructescence, it is roughly ellipsoidal, 6 to 10 cm high (2.2–4 in) and 4 to 8 cm (1.5 to 3 in) wide. Up to 25 smooth, elliptical follicles develop on the spike, each containing up to two wide wedge-shaped winged seeds. [4] One field study revealed, on average, eight follicles for each fertile cone. [6] Initially covered in fine fur, these are 2 to 4.5 cm (0.79 to 1.77 in) long, 1–1.8 cm (0.39–0.71 in) high and jut out by 1–1.8 cm (0.39–0.71 in). [2] The fur rubs off and they become smooth with wear, and generally remain closed until opened by fire. [2]
The seeds of Banksia grossa are the largest of all the species of the series Abietinae. Measuring 2.8–3.9 cm (1.1–1.5 in) long, they are made up of a cuneate (wedge-shaped) seed body, 1.4–1.8 cm (0.55–0.71 in) long by 0.4–0.9 cm (0.16–0.35 in) wide, and a 2.7–3.3 cm (1.1–1.3 in) wide wing. The woody separator is the same shape as the seed, with an impression where the seed body lies next to it. [2] The bright green cotyledons are obovate and can be either convex or concave, measuring 1.6 to 2.2 cm long by 0.9 to 1.2 cm wide. These arise from a stocky seedling stem, known as the hypocotyl, which is reddish and covered in short hairs. The auricles of the cotyledons are 2 mm long. Seedling leaves arise 0.6 to 0.8 cm beyond the cotyledons and are oppositely arranged. Linear, they are 1.4 to 1.6 cm long with recurved margins and are covered in white hair. The stem remains reddish. Subsequent leaf pairs are successively longer. [2]
The first known specimen collection of B. grossa was made by botanist Fred W. Humphreys in 1965. Alex George has expressed surprise that it was not collected by earlier visitors to the area, speculating that "perhaps they were diverted by its similarity to B. leptophylla and B. sphaerocarpa ." George formally described the species in his 1981 monograph "The genus Banksia L.f. (Proteaceae)", based on a specimen collected by him on the Brand Highway, 76 km north of Regans Ford, on 14 May 1969. He placed it 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. It was placed in phyletic order between B. micrantha and B. leptophylla. The specific epithet is from the Latin grossus ("coarse") and refers to the leaves, flowers, and fruit, all of which George observed were more coarse than other members of B. ser. Abietinae. [2]
George's arrangement remained current until 1996, when 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 was retained. It further resolved into four subclades, so Thiele and Ladiges split it into four subseries. Banksia grossa appeared as the most basal member of the second of these:
B. grossa | |||||||||||||||||||||||||
This clade became the basis for the new subseries Sphaerocarpae, which Thiele defined as containing those species with lignotubers, styles loosely curling around the infructescence (although this trait was reversed in B. micrantha), and "transversely aligned cells of the seed wing inner face". The species other than B. grossa also have shouldered follicles. [7]
Questioning the emphasis on cladistics in Thiele and Ladiges' arrangement, George published a slightly modified version of his 1981 arrangement in his 1999 treatment of Banksia for the Flora of Australia series of monographs. The placement of B. grossa was the same as in 1981, except that B. telmatiaea was moved to set between it and B. leptophylla. The placement of B. grossa in George's 1999 arrangement may be summarised as follows: [4]
Since 1998, Austin Mast has been publishing results of ongoing cladistic analyses of DNA sequence data for the subtribe Banksiinae. His analyses suggest a phylogeny that is very different from George's arrangement. Banksia grossa was inferred to be sister to a polytomous clade consisting of B. leptophylla, B. telmatiaea, B. scabrella and B. lanata: [8] [9] [10]
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B. grossa | ||||||||||||||||
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. grossa is placed in B. subg.. Spathulatae. [11]
Banksia grossa mainly occurs from west of Yandanooka in the north, south to Badgingarra National Park, and east almost to Coorow. It grows in shallow sand over laterite, in deep sand, and occasionally atop lateritic rises, on flat or gently undulating land, among kwongan shrubland. [3] [4] Around 40% of plants occur on road verges. [3]
Banksia grossa resprouts from its woody lignotuber after bushfire. Shrubs carry relatively low numbers of seeds compared with plant species that regenerate by seed after bushfire. A field study in Eneabba showed shrubs bore anywhere from 30 to 90 seeds per plant. Seeds borne on plants, however, are less likely to be eaten by animals than seed lying dormant in the soil, and hence survive to produce future seedlings. Populations of resprouting plants, like B. grossa, benefit more from longer intervals between fires as their stored seedbank takes longer to accumulate than reseeding species. [12] The follicles generally open after bushfire, releasing seeds which germinate after disturbance. [6] Species with persistent flowers on old spikes often require higher temperatures for follicles to open after burning; laboratory testing resulted in 50% opening after exposure to 270 °C and 90% after 400 °C. [6]
The leaves of B. grossa are adapted to a dry climate. The lower surfaces are protected by the strongly revolute shape of the leaf, the leaf margins curling around underneath almost to the mid-vein. The trichomes (leaf hairs) run along the mid-vein and the margins, further protecting the surface where the stomates are located, thus minimising water loss. [13] Cladistic analysis suggests this species and its relatives in the series Abietinae developed long narrow leaves with inrolled margins as they invaded drier climates in Australia's southwest, having evolved from ancestors with broad leaves. [9]
The inflorescences are highly attractive to insects. [5] The rare bee species Hylaeus globuliferus is a recorded visitor. [14] Large numbers of ladybirds have been reported drinking the nectar of this species, while ignoring nearby Banksia attenuata inflorescences. [5] The white-tailed dunnart (Sminthopsis granulipes) has been observed visiting flower spikes. Pollen has been found on the snouts and in the scat of several species of dasyurid marsupials, which suggests these animals are likely pollinators of Banksia species in general. [15] No pollinators of this species were recorded in The Banksia Atlas survey. [3]
Banksia grossa is one of five closely related Banksia species that have highly unusual flower nectar. [lower-alpha 1] Whereas other Banksia species produce nectar that is clear and watery, the nectar of these species is pale yellow initially, but gradually becomes darker and thicker, changing to a thick, olive-green mucilage within one to two days of secretion, and eventually becoming "an almost black, gelatinous lump adhering to the base of the flowers". [17] It was first noted by Byron Lamont in 1980; he attributed it to cyanobacteria that feed off the nectar sugars. Noting that many of these cyanobacteria had heterocysts, he speculated that they aid the plant by fixing atmospheric nitrogen, which is then washed off the flower heads by rain, and absorbed by the proteoid root mat. This purported symbiosis was investigated by Barrett and Lamont in 1985, but no evidence of nitrogen fixing was found. [18] Further investigation by Markey and Lamont 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". Their analyses indicated that the nectar had unusually high levels of sugar and free amino acids, [5] but three of these species, including B. sphaerocarpa, have since been shown to have normal nectar sugar compositions. [19] The purpose of coloured nectar is unclear, especially as pollinators such as nocturnal mammals are not thought to forage by sight. However, nectar that becomes more obvious by appearance or smell as it ages might encourage pollinators to prioritise it over newer nectar. It is possible the colour change is unrelated to pollination. [16]
Banksia grossa is cultivated for its attractive needle-like leaves and rusty-brown flower spikes, both of which can be quite variable in colour. This species favours well-drained sandy or loamy acidic soils with a pH of 5.5 to 7, and a sunny aspect. Once established, it tolerates dry spells. It can be pruned heavily as it resprouts from its lignotuber. [20]
Propagation is by seed. [20] The seeds do not require any treatment before sowing, and take around 14 days to germinate. [21] This is a slow-growing plant, taking 5 to 7 years to reach maturity and begin flowering. [20]
This banksia was featured on an Australian postage stamp in 2018. [22]
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.
Banksia attenuata, commonly known as the candlestick banksia, slender banksia, or biara to the Noongar people, is a species of plant in the family Proteaceae. Commonly a tree, it reaches 10 m (33 ft) high, but it is often a shrub in drier areas 0.4 to 2 m high. It has long, narrow, serrated leaves and bright yellow inflorescences, or flower spikes, held above the foliage, which appear in spring and summer. The flower spikes age to grey and swell with the development of the woody follicles. The candlestick banksia is found across much of the southwest of Western Australia, from north of Kalbarri National Park down to Cape Leeuwin and across to Fitzgerald River National Park.
Banksia menziesii, commonly known as firewood banksia, is a species of flowering plant in the genus Banksia. It is a gnarled tree up to 10 m (33 ft) tall, or a lower spreading 1–3 m (3.3–9.8 ft) shrub in the more northern parts of its range. The serrated leaves are dull green with new growth a paler grey green. The prominent autumn and winter inflorescences are often two-coloured red or pink and yellow, and their colour has given rise to more unusual common names such as port wine banksia and strawberry banksia. Yellow blooms are rarely seen.
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 hookeriana, commonly known as Hooker's banksia, is a species of shrub of the genus Banksia in the family Proteaceae. It is native to the southwest of Western Australia and can reach up to 4 m (13 ft) high and 3 m (9.8 ft) wide. This species has long narrow serrated leaves and large, bright flower spikes, initially white before opening to a bright orange that appear over the cooler months. The flowers are pollinated by honeyeaters. The ageing flower spikes develop woody seed pods known as follicles. B. hookeriana is serotinous — large numbers of seeds are stored in the plant canopy for years until the plants are burnt by bushfire.
Banksia incana, commonly known as the hoary banksia, is a species of shrub that is endemic to the south-west of Western Australia. It has hairy stems, narrow linear leaves, heads of bright yellow flowers and later, up to thirty-six follicles covered with greyish hairs in each head.
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 leptophylla is a species of shrub that is endemic to the south-west of Western Australia. It has narrow linear leaves, heads of yellow or pale brown flowers with a yellow or purple style and later, up to eight egg-shaped follicles in each head.
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 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 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 2 m (7 ft) high and 3 m (10 ft) 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.
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 blechnifolia is a species of flowering plant in the genus Banksia found in Western Australia. It was first described by Victorian state botanist Ferdinand von Mueller in 1864, and no subspecies are recognised. It gained its specific name as its leaves are reminiscent of a fern (Blechnum). B. blechnifolia is one of several closely related species that grow as prostrate shrubs, with horizontal stems and leathery, upright leaves. The red-brown flower spikes, known as inflorescences, are up to 20 centimetres (8 in) high and appear from September to November in the Australian spring. As the spikes age, each turns grey and develops as many as 25 woody seed pods, known as follicles.
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.