Banksia incana: Difference between revisions

 

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==Taxonomy==

==Taxonomy==

[[Carl Meissner]] noted the hoary banksia as a distinct form of ”[[Banksia sphaerocarpa]]” and in 1856 gave it the name ”Banksia sphaerocarpa” var. ”glabrescens” in [[Augustin Pyramus de Candolle|de Candolle’s]] ”[[Prodromus Systematis Naturalis Regni Vegetabilis]]”.<ref name=APNI1>{{cite web|title=””Dryandra sphaerocarpa” var. ”glabrescens”|url= https://id.biodiversity.org.au/instance/apni/540392 |publisher=APNI|access-date=8 May 2020}}</ref><ref name=”Meisn.”>{{cite book |last=Meissner |first=Carl |editor-last=de Candolle |editor-first=Augustin P. |title=Prodromus Systematis Naturalis Vegetabilis |date=1856 |publisher=Sumptibus Victoris Masson |location=Paris |page=453 |url=https://bibdigital.rjb.csic.es/viewer/14922/?offset=#page=463&viewer=picture&o=&n=0&q= |access-date=8 May 2020}}</ref>

[[Carl Meissner]] noted the hoary banksia as a distinct form of ”[[Banksia sphaerocarpa]]” and in 1856 gave it the name ”Banksia sphaerocarpa” var. ”glabrescens” in [[Augustin Pyramus de Candolle|de Candolle’s]] ”[[Prodromus Systematis Naturalis Regni Vegetabilis]]”.<ref name=APNI1>{{cite web|title=””Dryandra sphaerocarpa” var. ”glabrescens”|url= https://id.biodiversity.org.au/instance/apni/540392 |publisher=APNI|access-date=8 May 2020}}</ref><ref name=”Meisn.”>{{cite book |last=Meissner |first=Carl |editor-last=de Candolle |editor-first=Augustin P. |title=Prodromus Systematis Naturalis Vegetabilis |date=1856 |publisher=Sumptibus Victoris Masson |location=Paris |page=453 |url=https://bibdigital.rjb.csic.es/viewer/14922/?offset=#page=463&viewer=picture&o=&n=0&q= |access-date=8 May 2020}}</ref>

[[Alex George (botanist)|Alex George]] raised the variety to species status in his 1981 monograph “[[The genus Banksia L.f. (Proteaceae)|The genus ”Banksia” L.f. (Proteaceae)]]”, based on a specimen he collected outside the [[Moore River Native Settlement]], on 2 February 1967.<ref name=APNI>{{cite web|title=””Banksia incana”|url= https://id.biodiversity.org.au/instance/apni/538004 |publisher=APNI|access-date=8 May 2020}}</ref> He placed it in [[Banksia subg. Banksia|subgenus ”Banksia”]] because of its flower spike, in ”[[Banksia sect. Oncostylis|section Oncostylis]]” because its styles are hooked and in the resurrected series ”Abietinae”, which he constrained to contain only round-fruited species. The [[Botanical name|specific epithet]] (”incana”) is from the Latin ”incanus” (“[[wikt:hoary#Adjective|hoary]]”) and refers to the grey furry follicles.<ref name=”George 1981″ />

[[Alex George (botanist)|Alex George]] raised the variety to species status in his 1981 monograph “[[The genus Banksia L.f. (Proteaceae)|The genus ”Banksia” L.f. (Proteaceae)]]”, based on a specimen he collected outside the [[Moore River Native Settlement]], on 2 February 1967.<ref name=APNI>{{cite web|title=””Banksia incana”|url= https://id.biodiversity.org.au/instance/apni/538004 |publisher=APNI|access-date=8 May 2020}}</ref> He placed it in [[Banksia subg. Banksia|subgenus ”Banksia”]] because of its flower spike, in ”[[Banksia sect. Oncostylis|section Oncostylis]]” because its styles are hooked and in the resurrected series ”Abietinae”, which he constrained to contain only round-fruited species. The [[Botanical name|specific epithet]] (”incana”) is from the Latin ”incanus” (“[[wikt:hoary#Adjective|hoary]]”) and refers to the grey furry follicles.<ref name=”George 1981″ />

In 2008, George describe two subspecies and the names are accepted by the [[Australian Plant Census]]:

In 2008, George describe two subspecies and the names are accepted by the [[Australian Plant Census]]:

* ”Banksia incana” var. ”brachyphylla” <small>A.S.George</small><ref name=APC1>{{cite web|title=””Banksia incana” var. ”brachyphylla”|url= https://biodiversity.org.au/nsl/services/apc-format/display/214169|publisher=Australian Plant Census|access-date=8 May 2020}}</ref> – typically a mounded shrub with leaves usually {{cvt|10–20|mm}} long;<ref name=”George 2008″>{{cite journal |last1=George |first1=Alex S. |title=Further new taxa in ”Banksia” (Proteaceae: Grevilleoideae) |journal=Nuytsia |date=2008 |volume=18 |pages=55–56 |doi=10.58828/nuy00491 |url=https://florabase.dpaw.wa.gov.au/science/nuytsia/491.pdf |access-date=8 May 2020}}</ref>

* ”Banksia incana” var. ”brachyphylla” <small>A.S.George</small><ref name=APC1>{{cite web|title=””Banksia incana” var. ”brachyphylla”|url= https://biodiversity.org.au/nsl/services/apc-format/display/214169|publisher=Australian Plant Census|access-date=8 May 2020}}</ref> typically a mounded shrub with leaves usually {{cvt|10–20|mm}} long;<ref name=”George 2008″>{{cite journal |last1=George |first1=Alex S. |title=Further new taxa in ”Banksia” (Proteaceae: Grevilleoideae) |journal=Nuytsia |date=2008 |volume=18 |pages=55–56 |doi=10.58828/nuy00491 |url=https://florabase.dpaw.wa.gov.au/science/nuytsia/491.pdf |access-date=8 May 2020}}</ref>

* ”Banksia incana” <small>A.S.George</small> var. ”incana”<ref name=APC2>{{cite web|title=””Banksia incana” var. ”incana”|url= https://biodiversity.org.au/nsl/services/apc-format/display/214168|publisher=Australian Plant Census|access-date=8 May 2020}}</ref> – typically an open shrub with leaves usually {{cvt|30–50|mm}} long.<ref name=”George 2008″ />

* ”Banksia incana” <small>A.S.George</small> var. ”incana”<ref name=APC2>{{cite web|title=””Banksia incana” var. ”incana”|url= https://biodiversity.org.au/nsl/services/apc-format/display/214168|publisher=Australian Plant Census|access-date=8 May 2020}}</ref> typically an open shrub with leaves usually {{cvt|30–50|mm}} long.<ref name=”George 2008″ />

The variety ”brachyphylla” was described from a specimen collected at Big Soak Plain on the [[Coorow, Western Australia|Coorow]]–[[Green Head, Western Australia|Green Head]] road on 23 November 1999 .<ref name=APNI2>{{cite web|title=””Banksia incana” var. ”brachyphylla”|url= https://id.biodiversity.org.au/instance/apni/631207 |publisher=APNI|access-date=8 May 2020}}</ref>

The variety ”brachyphylla” was described from a specimen collected at Big Soak Plain on the [[Coorow, Western Australia|Coorow]][[Green Head, Western Australia|Green Head]] road on 23 November 1999 .<ref name=APNI2>{{cite web|title=””Banksia incana” var. ”brachyphylla”|url= https://id.biodiversity.org.au/instance/apni/631207 |publisher=APNI|access-date=8 May 2020}}</ref>

==Distribution and habitat==

==Distribution and habitat==

”Banksia incana” grows in sand in heath, shrubland or woodland, often with ”[[Banksia attenuata|B. attenuata]]” and ”[[Banksia menziesii|B. menziesii]]” and occurs between the [[Arrowsmith River]] and Perth.<ref name=”George 1981″/><ref name=”FloraBase” /><ref name=FloraBase1>{{FloraBase|name=””Banksia incana” var. ”incana”|id=33399}}</ref>

”Banksia incana” grows in sand in heath, shrubland or woodland, often with ”[[Banksia attenuata|B.attenuata]]” and ”[[Banksia menziesii|B.menziesii]]” and occurs between the [[Arrowsmith River]] and Perth.<ref name=”George 1981″/><ref name=”FloraBase” /><ref name=FloraBase1>{{FloraBase|name=””Banksia incana” var. ”incana”|id=33399}}</ref>

Variety ”brachyphylla” is found between [[Arrowsmith, Western Australia|Arrowsmith]] and [[Mogumber Nature Reserve|Mogumber]] with [[Disjunct distribution|disjunct]] populations near [[Gingin, Western Australia|Gingin]] and Perth.<ref name=”George 2008″ /><ref name=FloraBase2>{{FloraBase|name=””Banksia incana” var. ”brachyphylla”|id=33398}}</ref>

Variety ”brachyphylla” is found between [[Arrowsmith, Western Australia|Arrowsmith]] and [[Mogumber Nature Reserve|Mogumber]] with [[Disjunct distribution|disjunct]] populations near [[Gingin, Western Australia|Gingin]] and Perth.<ref name=”George 2008″ /><ref name=FloraBase2>{{FloraBase|name=””Banksia incana” var. ”brachyphylla”|id=33398}}</ref>

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==Conservation status==

==Conservation status==

Both varieties of ”B. incana” are classified as “not threatened” by the Western Australian Government [[Department of Parks and Wildlife (Western Australia)|Department of Parks and Wildlife]].<ref name=”FloraBase1″ /><ref name=”FloraBase2″ />

Both varieties of ”B.incana” are classified as “not threatened” by the Western Australian Government [[Department of Parks and Wildlife (Western Australia)|Department of Parks and Wildlife]].<ref name=”FloraBase1″ /><ref name=”FloraBase2″ />

==Use in horticulture==

==Use in horticulture==

Species of shrub endemic to Western Australia

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 incana grows as a shrub, typically 70 cm (28 in) high and 100 cm (39 in) wide with many stems arising from a woody lignotuber. The stems are covered with woolly, greyish hairs. The leaves are narrow linear, 10–60 mm (0.39–2.36 in) long and 1.5–2 mm (0.059–0.079 in) wide on petiole 1–2 mm (0.039–0.079 in) long and with a sharp point on the tip. The flowers are borne on a spherical head 60–70 mm (2.4–2.8 in) in diameter. The flowers are bright yellow, sometimes reddish, the perianth 21–23 mm (0.83–0.91 in) long and the pistil 30–35 mm (1.2–1.4 in) long and hooked. Flowering occurs from November to April and up to thirty-six prominent, egg-shaped follicles, 18–33 mm (0.71–1.30 in) long, 4–15 mm (0.16–0.59 in) high and 10–30 mm (0.39–1.18 in) wide form in each head, the old flowers having fallen. The follicles are covered with short, greyish hairs.^[2][3][4][5]

Carl Meissner noted the hoary banksia as a distinct form of Banksia sphaerocarpa and in 1856 gave it the name Banksia sphaerocarpa var. glabrescens in de Candolle’s Prodromus Systematis Naturalis Regni Vegetabilis.^[6][7]

Alex George raised the variety to species status in his 1981 monograph “The genus Banksia L.f. (Proteaceae)“, based on a specimen he collected outside the Moore River Native Settlement, on 2 February 1967.^[8] He placed it in subgenus Banksia because of its flower spike, in section Oncostylis because its styles are hooked and in the resurrected series Abietinae, which he constrained to contain only round-fruited species. The specific epithet (incana) is from the Latin incanus (“hoary“) and refers to the grey furry follicles.^[4]

In 2008, George describe two subspecies and the names are accepted by the Australian Plant Census:

• Banksia incana var. brachyphylla A.S.George^[9] – typically a mounded shrub with leaves usually 10–20 mm (0.39–0.79 in) long;^[10]
• Banksia incana A.S.George var. incana^[11] – typically an open shrub with leaves usually 30–50 mm (1.2–2.0 in) long.^[10]

The variety brachyphylla was described from a specimen collected at Big Soak Plain on the Coorow–Green Head road on 23 November 1999 .^[12]

Banksia incana grows in sand in heath, shrubland or woodland, often with B. attenuata and B. menziesii and occurs between the Arrowsmith River and Perth.^[4][2][13]

Variety brachyphylla is found between Arrowsmith and Mogumber with disjunct populations near Gingin and Perth.^[10][14]

Banksia incana resprouts from its woody lignotuber after bushfire.^[15]

Banksia incana is one of five closely related Banksia species that have highly unusual flower nectar.^[a] 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,^[19] but three of these species, including B. sphaerocarpa, have since been shown to have normal nectar sugar compositions.^[20] 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]

Both varieties of B. incana are classified as “not threatened” by the Western Australian Government Department of Parks and Wildlife.^[13][14]

Seeds do not require any treatment, and take around 14 days to germinate.^[21]