#4 Banksia marginata – the lonely Proteaceae

IMG_9732_500gBanksia marginata, common name Honeysuckle referring to the large amounts of bird-attracting nectar produced by the golden flower cones. Also known as Coastal Banksia, and Silver Banksia, in this case referring to the off-white hairy undersurface of the leaves. The Banksia genus was named in honour of Sir Joseph Banks. Species name marginata comes from Latin “marginatus”, meaning “with a border”, referring in botany to a distinct margin. This is one of only two Proteaceae species recorded on Maatsuyker Island,  (the other is Cennarhenes nitida, Native Plum), leading me to ponder why the Proteaceae family is so poorly represented. At home in the Blue Mountains where Proteaceae species are common, the sandstone soil is nutrient-poor. On Maatsuyker Island, large areas of soil cover are affected by the guano of the colonies of seabirds.

“As already noted, the diversity and abundance of Proteaceae increase from fertile to infertile habitats. Indeed it is only in infertile scrubs and heaths in the region that Proteaceae may completely dominate the canopy.”
Ecology of Proteaceae with special reference to the Sydney region
P.J. Myerscough, R.J. Whelan and R.A. Bradstock

Cunninghamia 6(4): 951–1015

This winter (2018), I have been studying the 11 Banksia species – including B. marginata – of the Blue Mountains where I currently live. Many Banksias flower through winter.  Their golden yellow/orange cylindrical spikes light up the bush and their nectar attracts many birds, including honey-eaters, and insects. The floral parts of the members of the Proteaceae family are unique and fascinating, so let’s delve deeper, specifically with respect to the Banksia genus.

The most common arrangement of reproductive parts in the plant world include female parts (aka pistil) – a single stigma, sitting atop a style, which receives pollen, and male parts (aka stamen) – several or many anthers, each sitting atop a filament, which produce pollen. However,  things happen a little differently in the Proteaceae family, including Banksias.

BanksiaSpinulosa_smThe easily recognised Banksia “flower” is a cylindrical cone-shaped “inflorescence”, or cluster of flowers; not just a single flower but hundreds of flowers, uniquely arranged. The photo on the left shows a B. spinulosa growing in my garden.

Careful inspection of the two cones reveals that they are at different stages of development. The foreground cone, shown below on the left, is a cone still in bud, while the background cone, shown below on the right, has more developed flowers. “Anthesis” is the process of the flower developing from bud stage to being fully open and functional, and in Banksias, this is very obvious because the style (female part) can be seen to extend way beyond the rest of the floral parts.

banksiaspinulosa_budcone.jpeg  BanksiaSpinulosa_LateCone

(The styles here are the deep purple “hooks”).

BanksiaMarginataCloseup_sm.jpegIn this close-up photo (left) of a Banksia marginata from my garden, you can see the flowers occur in pairs. And this is a cone still in bud, pre-anthesis, the styles have not yet fully emerged from the “perianth cup”. The perianth cup encloses 4 anthers, the stigma and the “pollen presenter” (more on that later!).

Usually the flowers develop from the bottom of the cone to the top, and if you look closely at the lower flowers, you can see the pale-green emerging styles.

Here are some photos of the emerging (purple) style from the Banksia spinulosa, taken with my USB microscope camera.

(1)BanksiaSpin_EmergingStyle1_sm   (2)BanksiaSpin_EmergingStyle5_sm   (3)banksiaspin_emergingstyle4_sm.jpg

Several families, including Proteaceae, have a highly-specialised floral structure called a pollen presenter, from which pollen is distributed (as opposed to the more common arrangement of pollen being produced and distributed in the anthers).  Pollen is deposited on the pollen presenter, an area at the tip of the style, pre-anthesis, i.e. while it is still enclosed in the perianth cup. Banksias avoid self-fertilisation, by keeping the pollen out of contact with the stigma.

 

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#15 Xerochrysum – Everlasting, Paper daisy

IMG_1837gNovember, 2017 Update

I have just submitted my drawing of Xerochrysum papillosum for the Botanical Art Society of Australia (BASA) Worldwide Botanical Art Exhibition to be held in Canberra in May 2018. This exhibition will feature the native plants of each participating country. Here is an image of my final drawing of this plant.Xerochrysum papillosum

February, 2017 Update…  Some new news: I was recently in discussion with a Tas Native Plant expert who had read this post and told me that this plant is in fact X. papillosum (not X. bicolor as I had concluded, see original post below). There has recently been a review of the Xerochrysum genus (published Jan 2017 in “Nuytsia”)  which can be found here. Many thanks to Mark Wapstra.

The paper states “The colour of the laminae of the involucral bracts remains the most obvious character that distinguishes X. papillosum from X. bicolor.”  You can see in the photo above that the bracts (white pointy petal-like structures) are white, whereas in X. bicolor they are yellow.

From “Tasmanian plant names unravelled” I learnt that the species name “papillosum” comes from the … “Latin papillosus (with papillae, small protuberances) alluding to the soft covering of hair-like papillae on the stems and leaves.”

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In the family Asteraceae, the Xerochrysum species have undergone a number of name changes. They were previously known as Bracteantha and/or Helichrysum, and you will still find them listed under these names in older pubs.

On Maatsuyker Island, I had trouble positively ID’ing the species. It was not listed on the plant list I was given before I went to the island.  IMG_8662gThere is not a lot of detailed keying information available and I suspect this is one genus that is not solidly nailed down..? The plants on the island have bright white (-not- pale yellow) phyllaries (the white bracts in the image above) when fully open, but in bud, the undersides are often tinged with pink. The disk flowers are bright yellow. IMG_1662gThe open flower head, or receptacle, measures approximately 4 cm across and 2 cm deep.

The leaves are long and narrow, up to 7 cm long and up to 12mm wide. They are very soft and flexible, and hairy! The underside of the leaf is paler green than the upper surface. The leaves are not as dense as on some common cultivar specimens. I measured one plant at about 38 cm tall. This is a photo of their habit. My conclusion is that the plants on the island are Xerochrysum bicolor but I am not 100% sure. This species is native to Tasmania where it is found in wetter habitats near the coast.

IMG_1827gOne of the identifying features of X. bicolor are fine barbs on the pappus (white furry bit on the end of the black seed pod, or achene). Here you can see the barbs on the pappus when the image is enlarged.

These everlastings were flowering when we arrived on the island in early December, and I was still recording and photographing flowers at the end of January. I only saw them on the track to the Red Shed, south of the “Tardis” (TV Repeater), i.e. west-facing before the track turned to the NE.  Although this part of the island is more exposed, the plants occur in the damper parts of the track.

IMG_0940gTas Government DPIPWE site lists X. bicolor as rare under the Threatened Species Protection Act 1995. There is a marker on its distribution map for one of the islands in the vicinity of Maatsuyker Is. with text “>50 years” which I think means recorded over 50 years ago….  interesting.

 

 

 

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#18 Exocarpos strictus – Native Cherry

IMG_9303GWhen I started this blog years ago, one of the main reasons was to construct an online, easily searchable and updatable repository of photos and information I gathered while researching and drawing/painting the plants I observed on Maatsuyker Island.  I usually start out with little knowledge of the subject but reading and questioning often reveal hidden secrets about the magic of our natural world that bring me great joy.  And so these days I approach each new blog post with an eager anticipation for the possible thrills that await.  The seemingly unremarkable Exocarpos strictus did not disappoint ….

Also known as Pale-fruit Ballart or Dwarf Cherry, this plant is the only member of the Santalaceae (Sandalwood) family to have been recorded on Maatsuyker Island.  During their visits in the early 1970s, Moscal and Bratt found it to be “abundant at all levels”.  I saw only a couple of specimens beside the track to the Red Shed, but of course I was limited to exploring the few existing tracks.

IMG_1743GThe genus name Exocarpos comes from Greek “exo” (outside) and “carpos” meaning fruit. The image (right) shows the 2-part conspicuous fruiting pedicel, about 4 mm long. The berry-like drupe (globular, on top) changes from green to yellow to orange to red and even purplish black. The swollen fruit stalk (pedicel),  seen here orange-pink, is edible and the seed (drupe) sits on top of it.

IMG_1749GThe plants on the island stand about 2m tall, with dense foliage which has that characteristic yellow-green colour of semi-parasitic plants. (Semi-parasitic plants obtain some nutrients from a host plant but also from their own photosynthesis.) Exocarpos strictus is a root parasite and host trees include Eucalyptus and, less commonly, some Acacia species. There are no Eucs in the vicinity of the plants I saw.  E. nitida, the single Euc on the island, is found only near the summit.  So perhaps the host tree is the sole Acacia species recorded on the island, Acacia verticillata, Prickly Moses. I  did photograph some specimens close to the Native Cherry, but I don’t know if this is the host.

The leaves of the tree are reduced to scales on the angled branchlets. IMG_9302GThey can be seen in the image on the right – small, pale,  triangular tooth-like structures. The yellow-green flowers are minute! only about 2mm in diameter.  Sadly my only flower image is poor. The plants were already in flower when we arrived on the island in early December, and they were finished within a week. The fruit was starting to form by early January.

A fascinating comment from a Victorian in blog  http://davesgarden.com/guides/pf/go/56969/ – “Now for the Kicker – I don’t plant these – I only culture them when my co-tennants plant them – As with most Santalums you need the local native furry creatures – in my case Anticinus – Kangaroo Rat – It seems the micro fauna in the saliva of the Anticinus triggers the seed – with santalums its the Dunnarts who plant them – Without this the strike rate is very poor – The creatures also know exactly where the roots for them to parasite to are and always plant them the same way – 4-5 seeds in a row planted in a groove left uncovered by the creature but quickly covered with gum leaves by the wind.”

IMG_1747GMaatsuyker Island is home to a large number of swamp antechinus, the only native mammal to be found there.  I find it intriguing to consider the symbiotic role that might allow the Native Cherry to survive on Maat.

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#17 Pimelea drupacea – Cherry Rice-flower

img_9183gA shrub with very attractive flowers in the Thymelaeaceae (Daphne) family. There are 90 species of the genus Pimelia endemic to Australia, but P. drupacea is found only in Tasmania, where it is common, and Victoria, where its conservation status is endangered. The genus Pimelea was named by Banks and Solander on Cook’s first voyage to the Pacific aboard Endeavour, while the species was named by Labillardiere on the d’Entrecasteaux expedition to Tasmania in 1792-3; “Pimelea” from the Greek pimele, meaning soft, fat, possibly referring to the seeds, “drupacea” meaning drupe-like fruit.  A drupe is a stone fruit (e.g. plum) – a fleshy fruit enclosing a seed.

img_1410gThe flowers are petal-less, with 4 silky-hairy sepals fused into a narrow tube with spreading lobes.  As shown in the photo (right), the flowers are white, sometimes tinged with pink.  They occur in dense clusters in the leaf axils or in terminal heads, surrounded by a group of bracts. (A bract is a modified leaf in the inflorescence, here standing below the flowers.. see the picture on the left.)

The leaves are simple, opposite and arranged in 4 ranks.

As the drupes form, their colour changes from bright green, then dark red, and finally shiny black. I saw many of these shrubs, up to about 2m high, along the track to the Red Shed.

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Lomatia tasmanica – King’s Holly

Photo – Natalie Tapson CC BY-NC-SA 2.0

A very special Tasmanian plant… for several reasons –

L. tasmanica is a member of the Proteaceae family. It was named for Deny King who first found the plant in 1934, and collected the type material in 1965. In 1969 eminent Tasmanian botanist Winifred Curtis confirmed it as a new undescribed species. “Holly” because of the shape of the leaves.

Although I searched, I did -not- find this plant on Maatsuyker Island. (I had been hopeful because I was not far from the south western area of Tasmania). I became aware of this amazing species during a visit to the Royal Tasmanian Botanical Gardens gift shop quite a few years ago when  I bought a note card with an intriguing photo of a beautiful red-flowered Grevillea-like plant.  I am familiar with several Lomatia species here in the Blue Mountains, but I had never heard of King’s Holly before. “By purchasing these cards you are helping to support the work of the Royal Tasmanian Botanical Gardens Rare & Threatened Plant Program”.  More information and lovely photos can be found at their website – http://gardens.rtbg.tas.gov.au/lomatia-tasmanica/

RTBG staff and other scientific organisations have worked hard to propagate the plant in order to maintain a viable ex-situ collection of L. tasmanica, but the task has presented many challenges. Recently there was a report of success in propagating this special treasure – http://www.abc.net.au/news/2017-04-08/growing-trend-towards-tasmanian-native-plants/8424804. This is very good news, as the single secret colony is threatened by both disease (Phytophthora cinnamomi root rot) and increased incidence of fire.

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#16 Coronidium scorpioides – an everlasting

IMG_2105gCommon name Button Everlasting, this glistening little gold jewel lights up the dense foliage along the track to the Red Shed. This plant belongs to the Asteraceae (daisy) family along with Acaena novae-zelandiae, Common Buzzy, Xerochrysum papillosum, and the Olearia species, as well as a couple of others that I have yet to document.

According to “Tasmanian Plant Names Unravelled” (my new bible) by Mark, Annie and Hans Wapstra, the genus name Coronidium comes from the Greek word for “crown, referring to the short pappus crown persisting on the fruit after the bristles have fallen off.”  A pappus is a “structure made of scales, bristles, or featherlike hairs that is attached to the seeds (called cypselae) of plants of the composite family and that aids in dispersal by the wind” (from dictionary.com). You can see a close-up photo of a pappus in my post about the paper daisy.

IMG_2135gThe genus has 17 species endemic to eastern Australia, but only one found in Tasmania. The species name scorpioides “describing the curling outer flower bracts” (scorpion-like?).  This same species is common in the Blue Mountains of New South Wales where I live, and is flowering now (March).

IMG_2105sgAn image of the flower-head, zoomed in.  The involucral bracts (outer, paler structures) are quite pungent (ending in a rigid sharp point – OUCH!)

According to PlantNET, this species has a synonym of Helichrysum scorpioides, originally named by Labillardiere.  In 2008, Coronidium was recognised as a new genus by Paul G. Wilson from the Western Australian Herbarium. See “Coronidium, a new Australian genus in the Gnaphalieae (Asteraceae)“. The author describes the morphological differences that justify some Helichrysum species (including scorpioides) being categorised in the new genus.

 

 

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My Maatsuyker Island Plant List

This plant list is a record of the plants I observed and studied on Maatsuyker Island during my artist residency. I am not a trained botanist so this list is informed by plant lists built by previous Maat visitors and my own identification skills. Therefore it should not be used as a definitive, accurate reference.

Acaena novae-zelandiae – Buzzy

Banksia marginata – Silver Banksia

Blandfordia punicea – Tasmanian Christmas Bell

Clematis aristata – Old Mans Beard

Coronidium scorpioides – Button Everlasting

Correa backhouseana – Coastal Correa

Drymophila cyanocarpa – Turquoise Berry

Exocarpos strictus – Native Cherry

Eucalyptus nitida – Smithton Peppermint

Leptecophylla juniperina – Common Pinkberry

Leptospermum scoparium – Tea-tree

Olearia persoonioides – Geebung Daisybush

Olearia phlogopappa – Dusty Daisybush

Pelargonium australe – Southern Storksbill

Pimelea drupacea – Cherry Riceflower

Pittosporum bicolor – Cheesewood

Stylidium graminifolium– Triggerplant

Thelymitra nuda – Sun Orchid

Xerochrysum papillosum – Paper Daisy

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