Tuesday, 22 July 2014

Pea flower more canary than butterfly

This is a canary, and these are the flowers of the Canary-bird Bush.

You won't get the two confused but you can see, perhaps, the point of similarity in colour and bearing. With flowers this large and showy, a bright little bird is not a bad analogy. For a plant botherer like me you can't help but wonder anew at the form and function of a pea flower, often described as papillionate, or butterfly-like.

Some flowers of the pea family are more like butterflies than this one but it has the typical bilateral symmetry, where there is only one way you can slice it to create two identical (but mirrored) bits. We call this zygomorphic.

The big petal sticking out the top is commonly called the standard, or sometimes banner, and less commonly these days (unless you read obscure taxonomic journal articles) the vexillum. It's the part that when broad and notched in the middle (in other genera) can look a little like butterfly wings. Below this is the keel, formed by two narrow petals at least partly fused together along their length, flanked by two wing petals. The reproductive goodies are gathered together inside the keel.

In the flowers of this Crotalaria agatiflora, the Canary-bird Bush, from the highlands of tropical east Africa (and the Grey Garden in Melbourne's Royal Botanic Gardens) the standard is spade-shaped, the wings quite small and like little tongues poking out the side of the brown tipped keel.

The Canary-bird Bush is just one of 700 or so species of Crotalaria, most of them native to Africa. Crotalaria is a member of the Papilionoideae subfamily of Fabaceae (or in some systems, simply the Fabaceae with the other subfamilies including cassias and wattles pulled up to family level).

As I said, the flowers are zygomorphic, as are most in the subfamily. There are a only a few with more complicated symmetry, e.g. the asymmetrical Vigna caracalla, the Snail or Corkscrew Vine (its flowers have weird curly bits but you'd probably still recognise these as variations on the papilionoid theme).

Pollination in papillionate flowers is usually 'brush type', where the male and female parts emerge from the keel in response to the insect rummaging inside the flower for nectar. In all my pictures the stamens and styles (male and female bits respectively) are well hidden, waiting perhaps forlornly in Australia for butterflies and bees heavy enough to part the keel.

The colour, the drama, and the size are all about attracting the pollinator and presumably guiding it to the bits that matter. I'm not sure about the dark brown spur on the keel but I bet that guides the insects in some way so that they assist the plant in its pollination.

Finally, the source of these flowers, our Crotalaria bush, a green bush with yellowish green flowers, nestled among grey plants in the Grey Garden. We also grow it in a couple of other places in the Royal Botanic Gardens. Up north, and even in far eastern Victoria, you might find it growing weedy in the bush: it's naturalised widely in the Southern Hemisphere, even in cooler countries such as New Zealand. So beware and be careful if you grow it, but do enjoy its papillionate, or canary-like, floral display.

Images all from the Grey Garden in Melbourne's Royal Botanic Gardens, except for the Canary, which is borrowed from LafeberVet.com

Tuesday, 15 July 2014

The deceptively dainty Sichuan Pepper causes a pleasant vibration

After the euphoria of our Gold Medal and Best in Show award at Hampton Court Flower Garden Show last week (and thanks for all the congratulatory tweets, emails and facebook posts) it's a return to a single species (or two) rather than a landscape. I took these pictures at the Dainty Sichuan restaurant in Toorak, an inner suburb of Melbourne (and the others at home after a little shopping), a few months back. We were treated to dinner by son Jerome, and his Sichuan-born wife Hao who knows her Sichuan Peppers. Her friends in Chongqing grew their own plants for their not so dainty (in a heat and spice sense) dishes.

These days most of us have eaten Sichuan Pepper fruits and experienced the tongue tingling sensation of 'sanshool'. Apparently, sanshool vibrates rather than tingles, causing a sensation equivalent to '50 taps per second'. Much like, again apparently, holding a vibrator to you lips.

Quite different to our table pepper and to chili pepper(s), although there are plenty of the latter in most Sichuan dishes as well (I remember one we had a few months back that consisted of 90% chili, 9% Sichuan Pepper and something else I can't now remember).

There is no point arguing over what is real pepper and what is not, or what was the first 'pepper'. That's what universities are for. Hadyn Druce's 2013 Master's thesis at the University of Sydney is a good place as any to learn about 'true' and 'false' peppers. According to Druce (and he uses an academically accepted and peer-refereed definition) true pepper comes from the fruit of a Piper species.

Piper nigrum (Black Pepper, from all over the tropics) is the most common source, but the Romans started it all with Piper longum (Long Pepper, from India originally). Druce lists 20 Piper species used to season food around the world. You'll most likely have black pepper on your dinner table, and given the sophistication of my Talking Plants readers I'm sure it is in some kind of grinding device.

False pepper comes from all over the plant kingdom, including the fruits of our favourite suburban and homestead tree, the Peppercorn Tree (Schinus molle), and the leaves and fruit of the Australian native Tasmannia. Chili (Capsicum) is quite different and not included by Druce as a pepper.

At the end of Druce's (alphabetical) list of 25 false peppers is Zanthoxylum piperitum and a few other species in this genus, all gathered together under the common name of Sichuan Pepper. Most species are native to China and Taiwan and its the fruit we eat.

I like Sichuan Pepper for the extra tingle (the 'ma') it gives to a spicy meal already fired up with chilli. So to do many Chinese. The two most commonly used species of Zanthoxylum are colour coded: Red Sichuan (Zanthoxylum bungeanum) and Green Sichuan (Zanthoxylum schinifolium - with a leaf like the Peppercorn Tree it seems).

Red Sichuan is native to the south-west of China, and would be the one Hao's friends grow and use. Green Sichuan grows further east and extends into Japan and Korea. These and other species of Zanthoxylum are also used to kill bugs and reduce inflamation, and (according to Druce) they appear in 'various skin care products'. A species native to North America, helpfully called Zanthoxylum americanum, is called the Toothache Tree - which I understand it soothes rather than causes. With its ability to cause a vibrating sensation, Scientists are hopeful Sichuan Pepper itself will help us better understand, and treat, the tingling associated with some chronic pain.

As to the botanical relationships of Sichuan Pepper, with such a pungent flavour and aroma you won't be surprised to learn its in the family Rutaceae, with things like citrus and boronias. Black Pepper is in the Piperaceae with not much else apart from the common garden ground-cover Peperomia.

Can you grow Sichuan Pepper in Melbourne? I doubt it. You also can't grow Black Pepper, so in southern Australia we are stuck with growing Capsicum (in the tomato and potato family, Solanaceae).

Tuesday, 8 July 2014

#EssenceOfAus ready for Showtime!

You can tweet your enthusiasm for our Hampton Court Palace Flower Show garden from anywhere on our planet using hashtag #EssenceOfAus, causing a ripple of pride in this small pond, in the Essence of Australia garden, in Hampton Court Palace, in London, UK, Earth, Universe etc.

After more than two weeks of carpentry, landscaping and planting, this patch of dirt (three weeks ago)...

...is nearly ready for the judges. This is what it looked like on Sunday, just after we finished adding the red stone and sand (carefully, like the reverse of an archaeological site dig).

For more pictures of the garden see the Royal Botanic Gardens Melbourne website, Facebook page or twitter feed (@RBG_Melbourne or @TimEntwisle). Or if we win a prize, hopefully you'll see it featured in a visual media outlet near you.

As this post goes to air, the awards will just have been announced (Monday afternoon London time, very early Tuesday morning Melbourne time). I'm either celebrating or downplaying the importance of awards with our (no matter what the verdict) prize-winning team. The decision was based on how well the garden 'meets the brief' so while you check social or other media for the decision, here is the intent.

The design was inspired by the Rainbow Serpent – an iconic creature from Aboriginal culture often seen in art and of continuing relevance today – with a nod to the Australian Garden at Royal Botanic Gardens Cranbourne. (The Rainbow Serpent features in Aboriginal dreamtime stories and is credited with forming the mountains, ridges and gorges as it emerged from beneath the ground.)

Towards the rear of the garden is a shelter that, as Jim Fogarty puts it, reflects "the simple, clean and stylish lines symbolic of contemporary Melbourne". The structure also references inland rock formations of the Northern Territory such as Uluru and the MacDonnell Ranges. The charcoal timber blades symbolise the water that cascades off these rock features when it rains, providing nourishment for Australia’s flora and fauna.

As visitors to the garden follow the Rainbow Serpent deck, they are asked to reflect on the natural attractions and landscapes of Australia, including rock seams and outcrops, where, again as Jim puts it "the endless roads delve deeper into rich aboriginal culture, red sands, and an amazing array of Australian plants". The deck includes a ford crossing, commonly found on outback roads that flood in the wet season.

It was also our intent to demonstrate, again, the beauty of the Australian flora and to use plants that are not hard to source in the UK. Some are hardy and should be grown more widely over here (the gum trees, westringia, and some of the grevilleas and bottle brushes), others would need some mollycoddling in winter (kangaroo paws, emu bushes), and a few will always be annuals (paper daisies, brachyscome). You can find out more about a few of them in my previous four posts.

Almost all the construction materials can be recycled, or reused, and all were sourced in the UK or nearby (the plants are from Spain and will be donated to Kew Gardens at the end of the show).

And in case you were wondering, this is the team that brought the Essence of Australia to Hampton Court Palace Flower Show:
Design - Jim Fogarty
Hard landscape: Landform
Plants: Hortus Loci
Planting - Chris Russell (Director, Royal Botanic Gardens Cranbourne), John Arnott (Manager, Horticulture, Royal Botanic Gardens Cranbourne), Russell Gibb (Coordinator, Horticulture; Royal Botanic Gardens Cranbourne), Kajsa Bjorne, Tom Harfleet, Peter Wilkins and Jane Wilkins
Rippling billabong: Tom Harfleet with help from Lincoln University
Fundraising and promotion - Ken Harrison (Chairman, Royal Botanic Gardens Victoria Board)
Scribe and other things - Tim Entwisle.
Plus a 'ground team' in Melbourne led by Susannah Jepson (Coordinator, Marketing (Events) at Royal Botanic Gardens Melbourne) under the guidance of Acting Director and CEO Jenny Steinicke, with Katie O'Brien and Robyn Merrett chasing up media. The whole caboodle was sponsored by Tourism Victoria, NT Tourism, Qantas, Trailfinders and us, the Royal Botanic Gardens Melbourne.


The Hampton Court Palace Flower Show starts today (Tuesday 8 July).

Tuesday, 1 July 2014

An Australian arboreal grass

Next week, show time! I'm in London now, at Hampton Court Palace, doing what Director's should do at this stage in the build - staying out of the way.

This gives me time to talk up Australian plants, the Australian Garden at Royal Botanic Gardens Cranbourne and even a little time to talk about Australian seasons, priming the British audience for my 1 September launch of Sprinter and Sprummer: Australia's Changing Seasons.

While I do all that, here's my final plant selection from the show garden, the grass tree. We only have three individuals, all Xanthorrhoea johnsonii, a species named in honour of Lawrie Johnson, Director of Royal Botanic Gardens Sydney from 1972 to 1985.

Johnson’s Grass Tree as it's called, grows naturally in north-eastern New South Wales and up into eastern Queensland. As you'd imagine from that sub-tropical range, it would need to be tucked up indoors to survived a UK winter.

There are 28 species of Xanthorrhoea, all of them native to Australia. The trunks (above or below ground) are often blackened by fire; fire which they need to flower and set seed. They used to be called Black Boys due to their fire-blackened trunk but this name is, at the very least, disrespectful to the first inhabitants of Australia.

These days we call most of them Grass Trees because that's very much what they look like. They are in their own plant family, within an higher group (an order) called Asparagales. They are also 'monocots', like grass, lilies and asparagus.

There are some magnificent grass-trees in both Royal Botanic Gardens in Victoria (Melbourne and Cranbourne). The five multi-branched Xanthorrhoea malacophylla (native to north-eastern NSW) on the lawns of RBG Melbourne are more than a century old. All of them exceed two metres in height, something rarely achieved in the wild.

In the Australian Garden at Cranbourne there is a charming clump of grass trees off the Eucalypt Walk, on west side of the Red Sand Garden. These are the same species as in our show garden, Xanthorrhoea johnsonii.

Where I can I've highlighted culinary and other uses of the Australian flora in my four Hampton Court Flower Show posts. In this case resin in the stem and at the base of leaves makes a useful adhesive. The botanical name of the Grass Tree in fact comes from the Greek ‘xanthos’ (yellow) and ‘rheo’ (to flow), a reference to this product.

Aboriginal people across Australia use Grass Tree resin to make tools, weapons and other implements. The resin melts when heated but sets hard when cool, so it's great for cementing stone axeheads to wooden handles and spear tips to spear shafts.

Like many other nectar-rich Australian flowers, particularly those conveniently clustered closely together like banksias and bottlebrushes, the flowers of the Grass Tree can be sucked, or soaked in water to make sweet drink (which like Cider Gum sap, can be fermented).

The soft, white leaf bases and growing tip are also edible, but removing the latter will kill the plant. Given it takes many decades to get a trunk the size of the specimens in our show garden, and a century or more to get to the size of the ones in Royal Botanic Gardens Melbourne, this is not recommended.

Images: the grass trees featured are, in the order they appear, Xanthorrhoea australis (I think) near the Grampians/Gariwerd, Xanthorrhoea malacophylla on Eastern Lawn in the Royal Botanic Gardens Melbourne (taken by Jim Fogarty, featuring yours truly), and Xanthorrhoea johnsonii in the Australian Garden at Royal Botanic Garden Cranbourne.

Tuesday, 24 June 2014

Blotto on blue gum

We are growing two kinds of gum tree in our Hampton Court Palace Flower Show garden. With a name like 'Little Boy Blue', the dainty cultivar of the Silver-leaved Mountain Gum (Eucalyptus pulverulenta) from grassy woodlands in southern New South Wales surely won't get you drunk. The other, the Cider Gum (Eucalyptus gunnii) from Tasmania, might just do it.

They both have waxy-blue, roundish leaves at first, and, if you allow them, longer sickle-shaped leaves (like those in frosty photo above) more typical of a eucalypt later in life: you can keep eucalypts forever young with regular and rather aggressive pruning.

Without pruning, Eucalyptus ‘Little Boy Blue’ could get to 20 metres, but it is bred from a mallee species, which means it's naturally multi-stemmed and typically more like large bush than a tree. Judicious trimming can keep it at 2-3 metres up and across. It should be hardy in much of the UK if given some protection from the worst of the weather (e.g. south side of a wall). We featured this cultivar in our gold-winning 2011 Chelsea Flower Show garden.

And the species, Eucalyptus pulverulenta, was featured recently on the Facebook page of the Australian Seed Bank Partnership, a national effort to conserve Australia's flora through seed collecting, banking, research and knowledge. On 13 May 2014 they excitedly informed their Facebook friends that seed from a natural population had been collected and stored.

Like Cider Gum, the bark is flaky, the foliage good for cut-flower arrangements and the flowers creamy and fragrant in spring. But no-one drinks 'Little Boy Blue'. Cider Gum, on the other hand, has been drunk, and undoubtedly some have been drunk on it. Whether you should, and whether you would benefit from that experience, is a question I can't answer.

You can be pretty sure from it's botanical name that Eucalyptus gunnii is from Tasmania. It was named by Sir Joseph Hooker, Director of Kew Gardens from 1865 to 1885, after the South-Africa-born plant collector and politician Ronald Gunn. Gunn spent most his life in Tasmania, gathering plants and plant enthusiasts, and he was highly regarded by Hooker. His name is hard to miss in any guide to Tasmanian native plants.

European settlers in Tasmania would tap Cider Gum like you would a Maple, to extract the sap from its trunk. Fermentation turned it into what has been described as a 'cider-like drink'. I suspect this means it has alcohol in it and tastes more like an apple than hops, barley or molasses. I think beer and rum were the other popular drinks of the time.

Like all eucalypts, it had other uses too. Any alcohol can make a handy antiseptic, but eucalyptus oil (unfermented) has been used to kill skin bacteria in Australia, and later around the world. These days eucalyptus oil is more commonly used to remove stains and treat colds and flu.

The first inhabitants of Australia were of course on the many uses of the gum tree already. Aboriginal people have used eucalyptus leaf oil as a disinfectant for tens of thousands of years. The also use sap for the same purpose, boiling it in water until dissolved and then rubbing into cuts and bruises. And heartwood diluted in boiled water was used to treat diarrhea.

Like the early Europeans settlers, Aboriginal Australians do digest eucalypts, using seed to make flour for damper, roots as another source of starch, and nectar drinks from the flowers of species such as the Manna Gum (Eucalyptus viminalis).

Making cider from Cider Gum was their idea too. In spring, Tasmanian Aboriginal people cut a hole in the trunk of the Cider Gum, eating the sap or boiling in water to make a thick syrup. Sometimes the syrup is used to make a cider-like drink, favoured for corroborees. There are some who think there is bigger market for a maple-syrup like product, or a fermented drink, from the Cider Gum. 

Until then, enjoy its aromatic blue leaves as a garden plant at home, or in our aptly named Essence of Australia garden at Hampton Court Palace in a couple of weeks.

Images: the top and bottom pictures are from one of the large and beautiful eucalypts growing near the Jodrell Laboratory in Kew Gardens, photographed on a frosty morning in December 2012. The others are images (taken by Jim Fogarty) from Viveros Medipalm, the nursery in Spain from where we sourced most of our plants for the show garden.

Tuesday, 17 June 2014

Cure for farting sheep spread through emu poo

Yep, a scatological post. Number two in the four part series featuring plants from our Hampton Court Palace Flower Show garden. This time is an Emu Bush, the Poverty Bush, or if you like, the Tar Bush.

Also known a little more formally as Eremophila glabra, the Common Emu Bush, is indeed spread far and wide in the poo of emus. They eat the fruits, digest away the outer coating and then deposit the seed here and there (far and wide) to disperse this beautiful grey bush with colourful flowers.

So this is a species that shouldn't become invasive in the suburbs of London, unless squirrels acquire a taste for the small fleshy fruits. But then eremophilas such as this one are also called Tar Bush because they are sticky to touch and can smell like tar - not the kind of plant I think a squirrel enjoys foraging from.

Most emu bushes grow in dry, inland areas of Australia, where they acquired another of their common names, the Poverty Bush (the botanical name, 'eremophila', also means desert loving). They grow in tough farming country, places where it's a struggle to make a living, and where any plant edible to stock is welcomed.

These are also places where sheep fart, as they do elsewhere. Some recent research out of the University of Western Australia, suggests planting more emu bush might solve global warming. Well not quite, but when part of a mixed diet (e.g. with oat chaff) feeding sheep with Eremophila glabra can reduce methane production (from farting and burping) while maintaining productivity.

The researchers imitated a sheep's stomach by fermenting various plants, then measured how much methane was produced. If Common Emu Bush was part of the mix, emission of the greenhouse gas methane could be reduced by nearly half. Nothing to sneeze at. As a bonus, feeding sheep emu bush might also help prevent lactic acidosis, a form of indigestion, in sheep.

Eremophila is not just attractive to emus and sheep. The flowers are pollinated by various (flighted) birds and insects, depending on their shape and colour. And there is plenty of variety. There are more than 200 species of Eremophila, all of them only found in Australia, with maybe another 70 waiting to be described.

While a pretty plant in the UK summer and tolerant of moderate frosts, it seems the Common Emu Bush will need to be taken indoors for winter if you live in London. When outside, try a sunny position in a well-drained soil.

In any country, the grafted specimens are definitely easier to grow. The root stock is usually Myoporum, the Australian boobialla, a genus that didn't make the cut for our July 2014 show garden.

Images are from central Australia, mostly taken in Olive Pink Botanic Garden, Alice Springs (the source of the wire emu sculpture too). The first emu bush I thought might be Eremophila glabra but astute and knowledgeable reader from Western Australia, Dave Bright, tells me it is Eremophila maculata (possibly var. brevifolia, which has short, rounded leaves). The flowers of Eremophila maculata have a long curved stalk rather than no stalk at all, as in Eremophila glabraSee also my posts on Eremophila gibbifolia and Eremophila debilis.

Tuesday, 10 June 2014

Desert Pea a black-bossed bloom in buccaneer's bounty

With four weeks until Melbourne's Royal Botanic Gardens exhibits its, and Australia's, first show garden at the prestigious (UK's largest and best attended) Royal Horticultural Society Flower Show at Hampton Court Palace in west London, I thought I'd feature a few of the plant species you'll see in Essence of Australia (#EssenceOfAus in the Twittersphere).

None of the plants are particularly odd or unusual to us Australians. In fact designer Jim Fogarty has selected plants that are easy to source and can be grown - some under glass, some as annuals - relatively easily in the UK. The design is deceptively simple but evocative, and the plants similarly so.

So one a week, for the next four weeks. The first is a showy but infrequently grown species with a knotty knomenclature, Sturt's Desert Pea.

While it looks good in almost any setting it's worth seeking it out in the near-deserts of central Australia, in all of Australia's mainland states except Victoria. As the wonderful Australian National Botanic Gardens website puts it, look out for calcareous, sandy soil in small depressions which channel water before it percolates into the soil.

Or, you can find it in most Australian botanic gardens and, since 1855, in the UK, where it was originally grafted onto the Bladder Senna, Colutea arborescens. These days it is sometimes grafted onto the similar looking, but not as closely related as some thought, New Zealand Parrot Pea, Clianthus puniceus.

Sturt’s Desert Pea was discovered by English buccaneer and early Australian tourist, William Dampier, on 1 September 1699. He was visiting Rosemary Island in the Dampier Archipelago, a group of 40 or so islands in northern Western Australia. Dampier collected a herbarium specimen (one of 10 species sampled) from “a creeping vine that runs along the ground ... and the blossom like a bean blossom, but much larger and of a deep red colour looking very beautiful". The flattened flowers and branch are now in the Sherardian Herbarium, Oxford (UK).

English, and Sydney, botanist Allan Cunningham collected it 119 years later from the same archipelago and Benjamin Bynoe, surgeon on the voyage of HMS Beagle with Charles Darwin, found it when he visited an island in the neighbourhood in 1840.

Inland explorer Captain Charles Sturt saw the plant in 1844, somewhere between Adelaide and central Australia, and his name is now attached to its otherwise very helpful common name. In scientific nomenclature, ‘Swainsona’ honours Isaac Swainson, who had a private botanic garden at Twickenham (a suburb of London) around 1789 and ‘formosa’, appropriately, is Latin for beautiful.

All sound simple, but it took some time to get there. In 1832 this unforgettable plants was finally described scientifically as Donia formosa, by Scottish Botanist George Don. His was an optimistic assignment given that Robert Brown described the genus Donia in 1813, based on Donia glutinosa (which is now Grindelia hirsutula) an American weedy daisy with yellow flowers commonly called Hairy Gumweed.

In 1835 is was more sensibly moved to Clianthus, a genus then and now confined to New Zealand and commonly called Parrot’s Beak. The flowers are similarly big and bold, and at least it's a pea. But this genus is now known to be unrelated to Sturt’s Desert Pea.

(When moved to Clianthus it was given the superfluous but nicely relevant species name dampieri; the species name formosa should have been retained. In 1950, this problem was fixed and it was for a few decades called Clianthus formosus - the ending gets adjusted to fit the gender of the genus name).

Then in 1990 it was moved to Swainsona, as Swainsona formosa, where it fits well in terms of our modern understanding of its form and its genetics. And there it remains, petty much.

There was a footnote in 1999 when Western Australian botanist Alex George thought its distinctive form warranted it being separated from other Swainsona, and set up a new genus Willdampia honouring William Dampier. But this would leave the rest of Swainsona unviable as a genus (we call it ‘paraphyletic’, when the taxonomic group doesn't include all the extant species from a common ancestor).

I hope I have all that correct. In any case, it's a black-bossed, beautiful blossom by any binomial.

Images: the top two are from a garden planting in Alice Springs (July 2008), a region where it grows naturally, and the bottom two from Australian National Botanic Gardens' new Red Centre Garden (March 2014).

Tuesday, 3 June 2014

Basil in the possumatouille?

Our backyard brushtail possums nibble on tomatoes, capsicums, grevilleas, hibbertias and marjoram, among other botanical delights. In fact they've dined on pretty much everything except the basil.

Rats, it seems, do like basil, but only in moderation. According to web advice for feeding pet rats, "it is high in calcium....too much calcium could cause bladder or kidney stones".

So the good news is that we have possums but not rats in our backyard. (Although there is a very rat-like creature that tracks across our back fence every night around dusk. Let's just say it's heading to a neighbour's property for its daily allowance of calcium.)

The other good news is that we have plenty of basil. Basil  is big business. From Royal Botanic Gardens Kew's Useful Plants and Fungi pages, we learn that each year around 100 tonnes of Basil oil is produced and the trade of Basil as a pot plant is worth something like US$15 million.

We also learn from those pages that common Sweet Basil, Ocimum basilicum, is almost hairless (the 'almost' allowing for the hairs you can see associated with its flowers, above) and that this separates it from closely related species such as Ocimum africanum, from Africa I presume, and Perennial Basil, Ocimum americanum, from you can guess where. Lemon-scented basil is usually a cross between Ocimum bascilicum and its African relative, and there are plenty of other species of Ocimum of culinary value.

Our basil's scientific monika, Ocimum basilicum, was bestowed on a plant collected in India, or nearby, and the species was probably originally native to parts of Asia further east such as Indonesia. Its cultivation seems to have begun in India and what is now called Iran, making its way to Egypt for use in mummification balms, and to Rome and Greece.

The flower shape and the aroma give away its familial affiliation: it's in the plant family Lamiaceae with mint (and our local mint bushes), rosemary, sage, marjoram, thyme and lavender.

The common name and species epithet for basil comes from the ancient and modern Greek word for a monarch, 'basileus', leading to the rather lazy designation of this condiment as the King of Herbs. With similar ease, let me finish with a more contemporary reference, the final episode of the immortal BBC comedy Fawlty Towers. As I'm sure you all know, Manuel thinks, thanks to Basil Fawlty, that his pet rat Basil (which he thinks is a Siberian hamster) is in the ratatouille. It isn't but hilarity ensues.

For me and our barkyard garden, there is plenty of basil - of the plant kind - but no other ratatouille ingredients thanks to our possum friends. Not on the menu, but worth noting, none of the possum casserole recipes I found on the web included basil.

Images of Sweet Basil from our backyard in April this year, as we prepared to collect seed for next year's crop.

And after this rather domestic post, the next four will be on plants to be featured in our show garden, 'Essence of Australia', at the RHS Hampton Court Palace Garden Show in London (8-13 July).

Tuesday, 27 May 2014

Elaeagnus's sweet perfume overwhelms starry scales

The first thing you notice is the sweet perfume, then the almost oak- or olive-like leaves, then the tiny white flowers and then, and only then, the rusty or white spots all over the leaves, stems and flowers. These spots turn out to be the most interesting part of the plant, to me.

So what are we talking about? A plant commonly called Oleaster, meaning it looks a bit like an olive tree. Botanically it's called Elaeagnus, and probably Elaeagnus macrophylla from Japan and Korea (or perhaps its hybrid with Elaeagnus pungens, called Elaeagnus ebbingei). This is the specimen I saw, and photographed, at Ripponlea in April.

Elaeagnus is one of three genera in the Elaeagnaceae, a family that used to be considered a close relative of our very own Proteaceae but is nowadays of uncertain placement in the plant tree of life, somewhere near buckthorns, elms, nettles and mulberries.

Elaeagnaceae is a family of three genera and about 50 species, with only one, Elaeagnus triflora, occurring naturally in Australia (in Queensland, and extending into tropical Asia). The common name for anything in this genus is Sliverberry or Oleaster, with Elaeagnus pungens  more often called Silverthorn due to its sometimes spiny younger growth.

In southern USA (e.g. Florida), Silverthorn is invasive in native forests, even climbing trees in the most favourable areas. In the Royal Botanic Gardens we have a large - very large - clump of what we call Elaeagnus pungens but looking more like Elaeagnus macrophylla (or perhaps a hybrid; it has large, very rusty undersided leaves with a more rounded tip) growing near the Tecoma Pavilion (filling in the left of this next picture). I could imagine this taking over a forest or clambering up a tree.

So far the species don't seem to be weedy in Australia but it would be worth taking care, particularly in gardens near native bushland. Birds love the fruit, to the extent that nearly 300 were killed in one month, over 100 in one day, trying to get fruits from bushes on a Texan roadside. The rusty, spotty, red fruit of the Silverthorn at least are apparently tasty to humans as well, and it sounds like most species have edible fruits.

Now to the rusty spots and dandruff-like white flecks. Above is a close up on the top and bottom surfaces of a leaf (just to confuse things a little, the top from Ripponlea, the bottom from near the Tecoma Pavillion at Melbourne's Royal Botanic Gardens). Both I could call stellate scales, or hairs - the brown ones a little flatter on the leaf. They have radiating 'arms' so they are what we call star-shaped or stellate, and because they are rather flat and flaky the word scale seems more appropriate than hair.

This indumentum, a lovely word, might also be described as peltate (scales), because although ragged they might be viewed as a flat disk with a stalk in the middle. The density of hairs/scales and their shape and form were variable across the individuals I looked at (which may belong to two or more species or hybrids), and a study on another Elaeagnus species showed strong environmental influence on such things.

In any case, pretty little things and not dots as they appear on first glance. I assumed they might be oil glands or something of that nature. Although the surface is pocked and blemished in various ways I think most of the obvious 'dots' are these stellate scales.

So attracted by the sweet perfume then on closer inspection, almost starry skies.

Tuesday, 20 May 2014

Alien gum tree vigorous and vibrant

I'll keep the focus on plants, not the recent vandalism at Melbourne's Royal Botanic Gardens. I couldn't do much better than start with this rainbow-coloured bark. It's not on display in the Gardens, yet, but given how fast the Rainbow Gum grows, if our 'seedlings' survive and continue to thrive we could have some within a year or two. What we have now are three plants just over a year old and already three metres tall. This one is flowering for the first time, after only 13 months...

It started as a seed, sown on 21 February 2013. Nursery horticulturist Dermot Molloy, in an nicely understated email, described it and its siblings as 'vigorous'. The three plants all look quite different. The other two are showing no sign of flowering but one has this lovely red-coloured new growth.

Our fear is that these vigorous seedlings might be as good as it gets. To get our first glimpse of the rainbow colours the seedlings of Eucalyptus deglupta need to survive another Melbourne winter, or two. We did have a sapling in our Rhododendron Garden which survived a few years but succumbed eventually to either possums, frost, drought, or all three.

So where to plant it for best chance of success? It comes from hot and wet climes, so you would think our Tropical Glasshouse would be best. However a few cuttings we tried there a few years back were susceptible to mildew and didn't survive. Given its growth rate and the height of our glasshouse, this would in any case be a temporary residence only. Somewhere like the Fern Gully might be best.

What about at Royal Botanic Gardens Cranbourne you might ask. Wouldn't a picturesque gum tree like this be perfect for our Australian Garden? For 800 or so species of eucalypt - EucalyptusCorymbia or Angophora - that would be true. But not Eucalyptus deglupta.

Although we got our seed from a grower in New South Wales, the original plant grew even further away, in the Philippines. It grows wild in the the Davao Oriental and Surigao de Sur area of north-eastern Mindanao. Which is why it is sometimes called the Mindanao Gum.

It also grows naturally in Papua New Guinea and various Indonesian islands, which is why it is sometimes called the Indonesian Gum (not, I think, the Papua New Guinea Gum*). But not in Australia. There are three other species of Eucalyptus native only outside Australia: Eucalyptus urophylla, Eucalyptus orophila and Eucalyptus wetarensis. They all grow in Timor and nearby Indonesian islands, but not Mindanao or anywhere else in the Philippine (there are an additional four species shared between Australia and Papua New Guinea). The Rainbow or Mindanao Gum is famous as the only eucalypt native to the Northern Hemisphere.

None of the other extra-Australian eucalypts are as pretty in the bark as Rainbow Gum. And none, it seems, grow as quickly. The Rainbow Gum is grown for pulp, paper and timber in various countries in the tropics.

As a naive eucalypt taxonomist (i.e. I know very little) I wondered why it wasn't a Corymbia. My simplistic caricature of a bloodwood is a gum tree with flowers at the end of branches like this.

But then the name Corymbia gives a clue - the flowers are arranged in what is called a 'corymb', which is not only a terminal bunch but one where the flowers all end up in more or less the same plane. The flowers on this Eucalyptus deglupta are rather more scattered.

In a collaborative project with researchers from the University of Melbourne, Bogor Botanic Garden in Indonesia, and Arnold Arboretum in the USA, our Research Manager Frank Udovicic actually knows something about its taxonomic relationships. And what he knows is that things are little uncertain.

Frank and his colleagues are comparing DNA sequences to determine where this species fits among the other 700 species of Eucalyptus, and what its closest relatives are. That might tell us more about the evolution of eucalypts generally, about their past distribution and perhaps interesting things like why and when they became fire adapted. For now though, I can confirm it is nestled safely within the genus Eucalyptus.

That said, the leaves of Eucalyptus deglupta don't smell much like a eucalypt. Dermot says they remind him a little of camphor. To me they smell more like a guava, or just plain 'leafy'. Either way, they don't seem to be full of the oils that make Australian eucalypts so flammable.

For now the three plants grow in large tube pots in our nursery. We'd love to get them out into the public display area, but only if we can be confident they will survive. If we leave it much longer we might have nother problem. Assuming they are as vigorous underground as above, we expect there are already a few roots heading towards London.

Images: The image at the top of the post is from the ZME Science site.
*Post-posting my botanical buddy Jim Croft tells me it is called Kamarere in Papua New Guinea, at least that's what he recalls. Another later, another bb, Alistair Hay, confirms.
**And also post-posting, I can point you to the complete genome of Eucalyptus deglupta, as sequenced by Michael Bayly and team, from the plant we used to have growing in the Royal Botanic Gardens! It says it all really - just a bit hard to understand... 

Tuesday, 13 May 2014

Weedy and greedy but buttercup no pain in the bum

Buttercups are usually applied to top end of the body, under the chin, to test your predilection for butter. If your neck glows yellow, butter is your thing.

While I can't explain the butter test, I can, thanks to some physicists via wired.co.uk, explain why the flowers are so reflective. It's down to a two layered upper surface on the flower, with a sliver of air between them. The yellow light is reflected by the smooth cells surfaces of both layers, and the air sliver, creating the extra lustre.

In the case of the buttercup I've illustrated here, Ranunculus ficaria (sometimes called Ficaria verna*) from the produce garden at Heidi Museum of Modern Art in Heidelberg (in August 2013), you should apply it to the rump region of your body. It's tempting to think it might be a way to see if the sun shines from there but no, it's to treat the unwanted symptoms of haemorrhoids. I'm presuming it's also a concoction from the leaves rather than the oh-so reflective flower.

The pilewort is native to much of Europe, where it is also known as the Lesser Celandine. Just to confuse things and to illustrate the benefit of scientific names, the Greater Celandine, Chelidonium majus, is a poppy relative and not in the same family as Ranunculus. The Greater Celandine is applied to warts (perhaps we should call it the Wartwort?) while the Lesser Celandine is applied to your bum, and gets called the Pilewort.

This is the warning on the Plants for a Future webpage for Ranunculus ficaria"All parts of the plant are poisonous. The toxins are unstable and of low toxicity, they are easily destroyed by heat or by drying. The sap can cause irritation to the skin. Do not use internally. Stop using the herb if breathing problems or chest and throat tightness."

Despite being 'easily destroyed by heat or by drying', the website notes further down that 'it is not recommended for internal use because it contains several toxic chemicals'. Despite minor irritations to sensitive-skinned souls, it has been used for thousands of years to treat haemorrhoids, apparently externally (more or less).

Should you decide to grow it (for personal use only), beware. It can be quite weedy and 'greedy'! In shade it forms bulbils (at least the subspecies bulbilifer does) at the base of the leaves and, 'you would regret introducing it into your garden' says the Plants for a Future website.

There are less invasive cultivars, apparently, including some that flower (at least in Cornwall, UK) earlier in the season, before the pollinating insects are about. Like many of our native sun orchids (Thelymitra) the flowers only open on sunny days, and then only after 9 am and before 5 pm (at least in Cornwall).

In Australia, where we generally call this species Ficaria verna (*Ficaria being a genus of 5-15 species sometimes segregated from Ranunculus with its 500 or so species), the species has escaped at least once into a semi-natural area around Lake Wendouree in Ballarat. Given its weedi- and greediness, I imagine it could easily spread elsewhere. 

Tuesday, 6 May 2014

Itching to identify Australian hibiscus relative

It took me a while to realise the bushy tree in our local park was a Cow Itch Tree, Lagunaria patersonia. I know the species but I'm more used to being more tree-like, with a visible trunk. Anyway, that's my excuse (along with the fading light) and I'm sticking to it.

Then when I tried to identify it from the flowers I was thrown for a while because they looked like some kind of strange Hibiscus. And indeed they are. Lagunaria is in Malvaceae family, along with Hibiscus and various other 'mallows'.

Embarrassing on both counts perhaps, but I like to think I know where to look for, and how evaluate, the relevant knowledge, even if at first I may be botanically baffled. So let's move on. (And a warning, this is another of those posts with lots of taxonomy and the like.)

In between my past and present sightings off a Cow Itch Tree, the plant family Malvaceae hadn't stood still. No sooner did I pronounce "Ah, yes, of course, Malvacae", than I discovered (or rediscovered to give me the benefit of the doubt) that Malvaceae has been the topic of much academic debate in recent years.

The Angiosperm Phylogeny Group is a collective of scientists (of the kind we call systematists) I've mentioned before. Let's call them The Group. Together they extracted DNA, correlated this with other evidence such as the way plants look, and then restructured the tree of life for plants.

Parts of the tree are relatively stable and not greatly changed from before their first publication in 1998. Elsewhere we have insights into the relationships between different groups of plants either from the first evolutionary trees in 1998, version II in 2003, or III in 2009. In some cases the position and/or circumscription of the family has bounced around between iterations.

The Malvaceae family is one that remains unsettled, even post-2009. Part of the problem is that there is no objective way to decide how big a family should be. Once we know the relationships between plants and how they merge together into successively larger units, we then have to decide where to draw a line through the branch and give that unit a name. The units have to have a common ancestor and include all its descendants, but within that constraint they can be as big or small as you like.

Stability, pragmatism and utilitarianism are usually guiding principles (in 2005, Peter Weston and I published a paper skirting around this issue in Australian Systematic Botany). In 2003 The Group found that some of the families closely associated with Malvaceae were tangled up with it, and there was no clear lineage you could hive off and call Malvaceae without increasing its size. They admitted that some of the subgroups (like Tiliaceae - including the Lime Trees I posted about last week - and the Sterculiaceae) were difficult to distinguish anyway and the new expanded Malvaceae would 'come as something of a relief'.

In between versions II and III, Martin Cheek from Royal Botanic Gardens Kew published (in Kew Bulletin) two new family names in what is called the order Malvales. Cheek's system of ten familes - called a 'novel dismemberment of Malvaceae' by the Angiosperm Phylogeny Group in 2009 - has not been widely accepted. It's said the families are difficult to tell apart and The Group comment on their website that 'the "very good reasons" for doing this are wanting'. For scientists this is pretty straight talking.

The Malvaceae Info sites sums up the current status with a line about lack of agreement on the placement of Malvaceae and its close relatives within the flower plants or on its subdivision. However the separation of the current broad family into its four traditional constiuents (Malvaceae, Bomabacaeae, Sterculiaceae and Tiliaceae) is 'untenable'.

So...to know that the Cow Itch Tree is in the Malvaceae doesn't mean as much as it used to, although eventually I'm sure we'll find out what holds the family together and some subtle and useful divisions within it. In the old days you could say it nestled in with hibiscus and abutilon. Today you'll find boababs, kapok, lime trees and the durian in there with it.

To say it's closely related to Hibiscus is useful and even though the flowers are more like other genera in the narrowly, and traditionally, defined Malvaceae this is a  helpful hint for identification.

It used to be that to know it's Lagunaria is to know that it's Lagunaria patersonia. Prior to 2006 there was only one species (albeit sometimes with two varieties or subspecies), growing naturally in mostly-coastal Queensland (perhaps from northern tip of NSW) and on two islands off the east coast of Australia, Norfolk and Lord Howe. Nowadays the mainland populations are usually called, conveniently, Lagunaria queenslandica. I'm assuming my local tree is of fair dinkum island origin, and still Lagunaria patersonia (sometimes miswritten as Lagunaria patersonii).

Lagunaria's closest relative, according to Malvaceae Info, is Howittia, a genus still with only one species, but this time growing only on the Australian mainland, further south, and again mostly near the coast.

The common names give you plenty of information too. The Cow Itch Tree tells you that the fruit (unopened in the picture above) is packed with fibre-glass-like hairs which are unpleasant when shoved down the back of your shirt by a so-called school friend. Norfolk Island Hibiscus tells you at least one place where it grows naturally and that it's related to a Hibiscus (note to self). Queensland Pyramid Tree gives you some idea of its shape (again note to self, although Queensland Blob Tree would be more helpful) and a bit more of its natural distribution, albeit now for the separate mainland species.

As for names like White Oak, Sally Wood, Sugar Plum Tree and Primrose Tree...well, who knows.