Tuesday, 22 April 2014

Tempted by the pomelo's sweet flesh but not thick albedo


I do like my grapefruits. Juice in the morning, and every now and then, one cut up as an evening snack. These days I'm a convert to the Ruby Grapefruit.

So I was pretty excited about seeing pink-fleshed pomelos, ancestors of the grapefruit, in the Singapore markets during the 15 days of New Year festivities in mid-February. The pomelo featured, along with Durian, as a special New Year fruit. Big and showy I guess, and the perfect gift. The pomelos are also bought in pairs to be made as an offering during New Year prayers.

That said, it's oranges and tangerines that are considered fruits of good luck for New Year. That's because, I gather, their names translate into Mandarin as something like 'luck'. Although it seems any orange-coloured citrus will do, and you most often see pairs of mandarins on a shop bench or a potted cumquat outside shops (and here in Singapore's Botanic Gardens).


But today it's all about the pomelo, or shaddock, a native of south-east Asia now grown widely in the tropics for its great big, citrusy, fruits.


There are various cultivars and the one I spotted was probably a Tambun Pink, originating from a farm further north in Malaysia.

At five Singapore dollars ($4.40 Australian) this was not a cheap citrus. In fact I shopped around to find this $5 bargain - $8 was the more common price and they are always in demand and expensive at this time of year. So I took my $5 fruit back to the hotel room to examine and eat.


The first thing you have to do is peel off the outer skin and rather thick albedo. The albedo is the white 'pith' under the skin of the pomelo. Rich in dietary fibre and other nice bits and pieces (antioxidants of course), this spongy substance is now being added to food, and burgers, as a supplement for good health. When eating a pomelo, or indeed any citrus, my preference is to discard as much of the albedo as possible.


There are websites explaining how to peel a pomelo, usually involving a sharp knife, but in my Singapore hotel room I attacked it with my bare hands. It wasn't pretty, but I got there.


The juicy cells inside the pulp looked, juicy. They were tantalisingly plump. I was expecting a bit hit of tangy sweetness: I know that while grapefruits are bitter in taste they also pack a lot of sugar as well. But given the pomelo (Citrus maxima) is one of the parents of the grapefruit (Citrus aurantium), the other being our more common sweet orange (Citrus 'valencia'/Citrus x sinensis), I thought it might be more down the bitter end, perhaps more like a lemon (Citrus x limon).

What a let down. My pomelo didn't taste awful, it just didn't taste. Not bitter, not sweet, not interesting, just nothing much at all. Perhaps I should have paid the extra $3? Or perhaps I should have eaten it as part of a traditional New Year 8-times-tossed, raw-fish salad like this one I enjoyed with the staff of Gardens by the Bay last month. Next time.


Images: the fruit and its deconstruction are from my recent trip to Singapore to visit the wonderful Gardens by the Bay. The fruits peeled in a basket, with other citrus nearby, are from a market in Dalat, Vietnam, visited in 2005. The pomelo trees are also from Vietnam, in Hanoi. The scale object in the unpeeled and peeled fruit pictures is a Myki Card, a credit-card-sized object used to ride trains, trams and buses in Melbourne. If you want to know more about the scientific names of various citrus fruits see David Mabberley's 1997 review.

Tuesday, 15 April 2014

Saraca's petal-less flowers confuse but are from the heartwood


More botanical highlights from Singapore. When I was visiting in February, Saraca was one of the most colourful and plentiful trees in flower. The clusters of mostly yellow, orange or red flowers erupted from all over the plant, all over the city.

The species photographed here is from the Singapore Botanic Gardens and is called botanically Saraca cauliflora (previously Saraca thaipingensis) in celebration of one place the flowers arise - from the trunks and stems ('caulis' is Latin for stem) - and commonly, the Yellow Saraca, in recognition of their colour (at least when young).


The Yellow Saraca is a local plant, native to the Malay Peninsula as well as further afield in the Indochina region and as far south as Java. There is a stream named after Saraca running through the Singapore Botanic Gardens. Along with the Yellow Saraca you can see the Red Saraca, Saraca declinata, and sometimes their roots trailing in the water (like weedy willow roots in many Australian streams).

Both these species, along with 70 or so others in the genus Saraca, are in the family Caesalpiniaceae (sometimes treated as part of the broader pea family, Fabaceae, which all bear their seeds in pods). Like me, you are probably more familiar with members of this family such as Cassia, SennaGledistia or Bauhinia.

Oddly, and unusually for this family, the flowers of the Saraca have no petals: normally it's the slightly irregular (actually bilaterally symmetric) display of petals that usually gives away the identity of a 'caesalpin'. In Saraca, the yellow or orange coloured segments are actually the outer layer of the flower, the sepals, folded back on the top of a narrow tube. The male bits, like your typical caesalpin, however, are sticking out strongly.


The flowers had little perfume in the stinking hot day I visited them, but I gather they do their thing at night. Evening perfumes are usually for bats or moths. The flowers are too small for nectar-eating bats I think and the colours too gaudy for moths - they start bright yellow and finish bright orange or red. More likely it's the birds that pollinate them, perfume or not, and plenty of nectar-feeding local species are attracted to them.

The leaves are divided up into matching pairs of leaflets and when young can have a gorgeous pinkish hue. It wasn't quite the season for new growth, but the pods are just as dramatic: large, flat and purple.


We can't, or at least we don't, grow Saraca outdoors at Melbourne's Royal Botanic Gardens. It doesn't like 'the cold'. While not the closest place to see them, I can recommend both Singapore Botanic Gardens and Gardens by the Bay, in February, for a memorable Saraca display (but no means done any credit but this photo of one of the larger trees I saw, in the botanic garden).


Images: All but the second picture are from a specimen labelled Saraca cauliflora, and had yellow flowers that turned to orange. The other one, labelled Saraca thaipingensis, seemed to have entirely yellow flowers.

Tuesday, 8 April 2014

Signing up to chunky flowered trees in Singapore


The Autograph Tree is so named because you can scratch your name on its leaf and that autograph will remain for the life of the appendage. This is probably true of most leaves but in this case the leaf survives your mutilation.

There are over 300 species of the leathery-leaved Clusia, the Autograph Tree, all from the tropics of central America. Many start as epiphytes, plants attached to other plants, but in time they overwhelm their host with roots and form their own trunk, much like the strangler figs.

There are separate male and female flowers, but both occur on the same individual. The flowers are as chunky as the leaves, often looking like porcelain or wax.

Some grow as mangroves, including the plants I'm featuring today, Clusia minor.  A mangrove is not a taxonomic category but a life form. Mangroves are a group of about 50 species that occur in intertidal mudflats, surviving inundation by salty water twice a day and often producing roots that seek out fresh air above the sea.


I photographed these relatively young Clusia minor (they grow to 10 metres in height) from the foreshore at Gardens by the Bay, in Singapore. They look to have been planted in the last couple of years. The species is native to the dry savannahs of Caribbean islands and mainland Central America but planted throughout the tropics.

I was captivated by the flowers. Firstly by their texture and shininess, then by their odd structure. I just couldn't work out whether they were the male or female flowers I was seeing, and just what was what inside that highly polished bloom.


There were no fruits, unfortunately. This is a picture I've copied from a fascinating blog about the plants of Panama. It's also the source of my initial identification (as Clusia pratensis, now considered to be the same as Clusia minor).


My Panamanian blogging colleague, Mary Farmer, had sought advice from Missouri Botanical Garden. Among the diagnostic features of this species given to her were that the flowers don't produce stamens (the male, pollen-bearing parts). Now the female flowers wouldn't be expected to produce them anyway but I couldn't find any flowers with stamens.

As Mary points out, the green blob in the middle is the female part, where pollen would normally land and stick for fertilisation. The sticky brown circle is presumably a ring of nectar to attract pollinators, although they have little to do in this species. It produces fruits without fertilisation it seems.

I'm still not quite sure if Clusia minor bears only female flowers, or whether there are male flowers that appear occasionally and perhaps they are infertile. Always more to learn, which is just fine by me.


While we are on the subject of quirky, chunky flowers in the parks and gardens of Singapore. I can't resist a few pictures of the Cannon Ball Tree, Couroupita guianensis. This is unrelated to our Clusia (and to what is called the Cannonball Mangrove) but it does have rather spectacular flowers.


In this case they turn into cannonball like fruits that split open to release a foul odour. You can see them all over Singapore, even as a street tree, but this one is inside Gardens by the Bay. Yet another reason to visit!

Wednesday, 2 April 2014

Breaking Dioon News: the girl's a boy!


Some of my posts are copied (and in the process made far prettier) into the award-winning GardenDrum, usually accompanied by a recording by me reading the post into my mobile phone. So you can read and hear (some) TalkingPlants.

The benefit of this is that more people get to find out what I think is interesting in the plant and garden world, and more people get to give me feedback on what I write (and say). (I also have an automated system in place to send out a tweet (follow @TimEntwisle) and Facebook post each time the blog is updated. Again I get feedback through these sites as well.)

Often enough I get a gentle correction, which I do appreciate. For me the fun in writing these posts is learning more myself about plants I know only a little about, or perhaps thought I knew more about than I do.

Anyway, this extraordinary (non-Tuesday) post is to report breaking news, predicted by a reader of GardenDrum three days ago (31 March 2014), when Craig Thompson added the following comment to my coning of the dioon post:

Thanks Tim for putting your appreciation of cycads out there for others to read. They are much maligned by the general public as being too slow or being too spiky to warrant growing. The common cycad most people can buy and grow is Cycas revoluta from Japan. Check out your real estate for sale section in the local papers and you will find them in nearly every property for sale. They do exude that expensive look. But more often than not, they are planted without regard to their eventual size and need to be removed or relocated. 

Not so with Dioon edule. My experience with these plants go back to the early 80′s and I have found that toenails grow faster. The new growth, which can be as little as twice per decade, is indeed beautiful. Their radial symmetry is breathtaking, as it is with most cycads, but they are just so slow. 

My first Dioon edule coned about eight years ago. It would seem that it, like yours, is the dwarf form – possibly angustifolium. But sorry to burst your bubble – I feel that yours is a boy. I do hate sticking my neck out, preferring to keep it down, but I feel pretty confident with my assertion. It is very hard to diagnose from a photo, but as it appears different from what I remember of mine, which subsequently was female, I bet yours elongates and drops pollen. Perhaps ours could mate in the coming decade(s).

Sure enough, our cone is elongating... Dermot Molloy, our trusty horticulturist in charge of Dioon cultivation, reported this morning in response to me sending him Craig's comments: 

The Dioon cone is now elongating more than a female would and I would have to agree.  The last couple of days has seen the cone really develop large gaps in a spiral formation.  


The pictures in this post were taken this morning (at around 9 am, 2 April 2014), from a bump on 20 February and a swollen 'girl-like' cone in mid-March (images of both in my last post). You can see in this close-up a modified leaf (the microsporophyll) bearing small round beads (the microsporangia). Each of the beads will release pollen.

So there you have it. We have a boy, not a girl, and perhaps a step closer to the correct botanical name. But still no mate on this occasion.

Thanks Craig, and thanks GardenDrum!

Tuesday, 1 April 2014

Purge and repel (Plant Portrait VII*)



If you are after a good laxative or goose repellent, look no further than your closest Rhamnus, Senna/Cassia, aloe or rhubarb (root). You can also select from among certain fungi, lichens and insects.

But take care! This column should definitely not be taken as reliable medical advice and many of these sources are also rather toxic in the wrong quantities. It's also April Fools' Day so who knows what you can believe. And a warning: this post includes chemical and botanical names, as well scatological references.

The active ingredient in life-enhancing (if constipation and geese are your problem) tonics prepared from these critters is called anthraquinone, or when sourced from Rhamnus purshiana (one of the buckthorns), also cascra sagrada.

Leopold Bloom, in Joyce's Ulysses, amuses himself with the efficacy of 'one tabloid of cascara sagrada' as he succeeds in his morning bowel movement on 13 June 1904. (Bloom is reading Mr Philip Beaufoy's column in the magazine Tit-Bits, which he subsequently uses to wipe himself clean.)

Cascara sagrada means sacred bark, a name given to this product by the Spanish arriving in America. It is the bark that is used as a laxative, and that bark contains anthraquinone. The fruit and honey are edible but also have a slight laxative quality.

The light yellow crystals of anthroquinone are also used in the manufacture of 'vat dyes', water-insoluble dyes renowned for their brightness and persistence. You'll find the same chemical in some pesticides and in the production of paper from pulp. Of botanical interest, athroquinone is used to treat seeds of other plants, to ward off various grain-eating birds. It also doubles more generally as a goose repellent.

Anthraquinone can be made soluble by adding reducing chemicals, such as sodium hydrodsulfite. You do this to get it absorbed by the cloth or seed coat before it becomes insoluble again and thereby stays put.

Apart from being insoluble in water, our yellow chemical of choice doesn't interfere with the germination of the seed, and deters but doesn't kill the birds. Birds vomit after eating seed coated in anthraquinone, but they survive to tell the tale. Interestingly, though, some sneaky birds will eat just a few seed - not enough to get sick - and then come back later for a few more.

Rhamnus purshiana is native to western North America and I can't find much record of it growing in Australia. It certainly doesn't appear on our Royal Botanic Gardens plant census. A Portland nursery quotes a description of this species as 'an alder crossed with a birch with a cherry thrown in'. Which is a bit what it looks like in this picture taken by Paul Schlichter, copied from Flora and Fauna Northwest (USA) site.


In the spirit of looking for obscure references to just about anything in Ulysses, I can find nothing else about laxatives or buckthorn (although a cad called Buck Mulligan does feature in the first chapter) and only one other reference to geese. Earlier in Ulysses, Stephen Dadalus imagines a drowned man and reflects that 'god becomes fish becomes man becomes banacle goose becomes featherbed mountain'. Make of that what you will - many have.

Images: The sketch of Leopold Bloom at the top of this post is by James Joyce, from Out of Print site.

Tuesday, 25 March 2014

The coning of the dioon


To paraphrase the 1843 paper describing this species for the first time, the addition of a new cone to our Cycadaceous collection is indeed a fine thing. Over the last month or so, one of our cycads has been constructing its first cone. Exciting times in the nursery at Royal Botanic Gardens Melbourne.

It's also the first time this particular species has 'coned' in our care, and it's a girl**: cycad plants are either male or female. Although 'commonly cultivated' according to Gardening Australia's Flora we have only one specimen of Dioon edule. And a pretty little species it is, with a lovely waxy bloom on its leaves (which may fade with age).

Our cycad growing expert, Dermot Molloy, describes the species as a very hardy Dioon from the Sierra Madre Oriental Mountains in Mexico. Loran Whitelock, in his book The Cycads says this species grows naturally in rocky areas and cliffs between tropical deciduous forests and oak woodlands. There are number of separated populations, each of which has gathered its own distinct leaf form and colour.

Whitelock says the current split into two varieties (one from the states of Nuevo León and Tamaulipas, and sometimes considered to be a distinct species called Dioon angustifolia) is simplistic. Eventually, he says, with more study, there will be more species named. So the important thing is to know where your specimen is from. Whitelock documents five variants: Valles, Río Verde, Querétaro, Jacala and Palma Sola.


Our seed came from somewhere a little closer to home, a grower called Peter Heibloem, at Eudlo Cycad Gardens in Nambour, Queensland. Peter collected all over the world in the late 80's early 90's but unfortunately he didn't provide a precise location for this collection. While the waxy grey foliage is distinctive, it doesn't seem to be a useful identification character.

Sydney's The Cycad Pages is a little helpful, citing three groups on the advice of Jeff Chemnick. The diagnostic features are whether or not the leaves (the full 'fronds') are flat or keeled, and the degree of overlapping of the individual leaflets. Ours have pretty flat leaves with leaflets that hardly overlap. This, I think, puts them in with the first described population from Chavarillo (Vercruz), or perhaps Rio Pescados which is similar. That's a good, and as close, as we can get at the moment.


The species as a whole is not uncommon, or under great risk, yet many have been collected from the wild for cultivation or lost through land clearing. There is an unfortunate market in the head (including the growing tip) with the leaves intact as a decoration. This stops the plant being able to produce new cones. Given the variety within the species it will also be important to conserve individual populations. As the species name implies, the seed has been eaten by humans in the past, but not much today.

Even if we can't track down the variety (named or unnamed) it's a pleasure to have a Dioon doing its thing. 'Dioon' is Greek for two eggs, a reference to the pairing of seeds within the cone, something we won't get to see without a male plant. There are 10 more species, all but one (which is found further south, in Honduras) from the coastal mountains of Mexico. Most develop long trunks, up to 15 m tall, making them look very palm-like at a distance.

Dioon edule reaches only three metres, at most. Ours is young and barely above the ground. It has grown from a seed sown on 31 March 1992 so it's taken 22 years to produce this cone, starting as a bump on 20 February and turning into this last week.


We'll be on the watch out for a sticky secretion, indicating that the ovules** are mature and the plant is ready to accept and draw down any pollen that lands on the cone. As you know, that won't happen this time because there are no males around to provide the pollen needed. But plenty of opportunities to come, this being only the first of hopefully many cones. Cycads can live, in the wild, for up to 1000 years. Take a look at this 240 or so year-old Encephalartos altensteinii in Kew Garden's Palm House. It's thought to be one of the oldest pot plants on Earth and was viewed, in fruit, by Sir Joseph Banks in 1819. Perhaps our dioon will attract similar attention on one of its next conings*.


* As distinct from coning and coning.
** Well, we made a mistake. Our girl is a boy! I've posted an update, with pictures, on 2 April 2014.

Tuesday, 18 March 2014

Heavy metal mother-in-law's tongue flowers



We plant Sansevieria for its attractively patterned leaves (which stray awfully close to variegation, something you know my views on), its hardiness (it does come close to thriving on neglect) and its snickeringly humorous common name (Mother-in-law's Tongue).

Here's another reason to grow it - a spectacular bunch of flowers. In February we had this species, Sansevieria metallica in flower in Melbourne's Royal Botanic Gardens Tropical Glasshouse.


The flowers are actually in pairs or clusters of up to four, and these are grouped together into the stalked flowering structure you can see at the top.You seldom see them in flower, either in nature or in glasshouses. A few other species (e.g. Sansevieria trifasciata) flower more often, but even they are not reliable bloomers. And the result is hardly as pretty as our Sansevieria metallica.


Mostly all you see of this plant is a couple of leaves variously blotched pale green or yellow. With age the discolouring fades. You can find a full description of the species from fan page of  the Angiosperm Phylogeny Group III Asparagaceae subfamily Nolinoideae... They get their information from a 1915 review of the genus Sansevieria, published only 12 years after our species was first described and used. Yep, published scientific research published 99 years ago and still relevant.

One of our nursery staff, David Robbins, tried to pollinate the flowers but was unable to find any pollen. Plenty of anthers but none of the gold dust. The female bits were sticky and ready, but sadly nothing for them to accept. In nature moths do this job, although not very well. Fruits are uncommon.


Because moths do it, the flowers are at there best in the evening. In fact in the morning all you get are spent flowers and buds, as in this picture I took just before lunch about mid-way through the flowering cycle. So you get a few waves of flowering, from about 3 pm each day, over a week.

Once the plant has flowered it no longer produces any new leaves. According to web gossip it doesn't die, like an Agave or Fucraea, but because the flower is produced by the leaf-producing growing tip there is no more action above the ground. The leaves remain as long as they remain undamaged and the plant may do a little expanding from underground stems called rhizomes.

Oh, and its species name refers to the sheen on the leaves rather than any prescience about a rather poppy and popular heavy metal band a third as old as the review paper on Sansevieria. You do the math.

Wednesday, 12 March 2014

Botany integrated into program of life science*/Let's sing the praises of taxonomists**



TIM ENTWISLE THE AUSTRALIAN MARCH 11, 2014 12:00AM*

I WAS at a conference last week where it was argued that we are living in a new geological period, the Age of Modern Man, the Anthropocene. This isn’t necessarily a good thing. As our impact on the planet grows, and climate change starts to bite, the Anthropocene may be one of the shortest geological periods on record. And it looks like we’ll take a lot of the planet’s plants and animals with us.

The title of my presentation was curing plant blindness and illiteracy. I spoke about the importance of plants to surviving and prolonging the Anthropocene, and what botanic gardens and botanists can do to help mankind in this time of trouble - from raising the standard of botanical literacy through to investing in seed banks and research.

Returning to my office in Melbourne’s Royal Botanic Gardens, I was greeted with news of a more imminent mass extinction, that of the word botany in our universities. Soon there may be no school or department of botany in an Australian university, and few anywhere in the world.

This doesn’t mean plants won’t feature in the university curriculum and research. New departments of biological science are forming from an amalgam of botanical and zoological schools, sometimes gathering up agriculture and various environmental units. Botany, or plant science as we like to call it these days, will be part an integrated program of life science.

While it could be argued that these new arrangements simply reflect our better understanding of the world, where plants and animals and various other organisms all interact and interconnect, we run the risk of losing something fundamental and important. That’s the ability to discern and understand the organisms with which we share our planet.

Some of these new departments may do botany as well, or better, than those who used to have the moniker nailed to the front door. While I value history and the word botany has strong links to my undergraduate and postgraduate years, it isn’t for those reasons I question the loss of this botanical identity. As with school curricula, we keep adding to the university syllabus as new knowledge is created, without any deletion. Molecular biology is immensely important and influential but it has been shoe-horned into biological teaching taking much of the space previously allocated to understanding the plants (and animals) that carry the molecules. Embracing molecular methods is essential but not at the expense of basic botanical knowledge.

The mega biological departments being created today are generally split into the mode of study - molecular biology, environmental biology, evolutionary biology, ecology - which makes some sense, but I wonder if in the end we lose too much in the translation. I find cross-disciplinary conferences such as the one last week fascinating and informative, and I welcome any chance to break out of my organismal
silo.

In the case of the School of Botany at the University of Melbourne, the one I know best, I am hoping the writing remains on the bronze plaque and not on the wall. Its branding is incredibly strong. Internationally, the School of Botany has a reputation for excellence in research and teaching, and locally it has used its foundation to raise money for projects such as $1 million for a joint post-doctoral position with the Royal Botanic Gardens, whose own foundation raised matching funds. This is a baby worth pampering.

Plants and their botanical relatives are survivors. We sometimes forget that blue-green algae ruled the Earth for three billion years. It was a long time ago; before the internet and even before the dinosaurs. The dinosaurs themselves stomped around the planet for 160 million years or so before a giant meteorite hit Earth.

We humans have been here for less than half a million years, with close relatives going back two million years at most. A tiny blip in geological time. Indeed there is debate around whether we warrant a geological age for ourselves, whether our time on this planet will leave a sufficient mark in what is called the stratigraphy.

Botany has already earned its place in geological time. Close descendants of the aforementioned algae are still alive today, and the flowering plants bloomed for the first time about 140 million years ago. We would do well to understand how they have survived for so long, and to apply our modern science in the context of their diversity and biology. I’d like to think the discipline of botany might survive another century or two, or at least to the end of the Anthropocene.


Tim Entwisle is director of Royal Botanic Gardens Melbourne.

*This is a copy of an opinion piece published in The Australian on 12 March 2014. 

**Follow this link to an opinion piece published in the Guardian (Australia Edition) on 13 March 2014 about the the plight of taxonomists (plant and otherwise).

Tuesday, 11 March 2014

Protean mimetes imitates life (Plant Portrait VI*)


Does this flower remind you of a rabbit's tail, a duck's feather or perhaps a droopy dandelion head? If you could see past the fluff you'd think it more like the flower of a grevillea or banksia. It's a relative of theirs called Mimetes.

Mimetes are people that imitate, represent or simply copy what someone else has done, or so say the linguists. Mimetikos is something capable of, and subject to, imitation. The word mimic comes from the same origin and there are books written about Mimesis*, 'art imitating reality'.

Keen gardeners and plant-lovers will be familiar with this botanical Mimetes, a genus of protea-like plants from South Africa.

It's unclear why, in 1807, Richard Salisbury named the genus 'mimetes'. It may be because all 14 species look very similar - that is, they imitate each other - or because the genus looks a bit like Leucospermum. Yet the name is almost ironic given how distinctive this genus is in flower from any other plant. No one writes of the flowers imitating some creature, such as a rabbit or duck, to encourage their pollination.


All the protea family genera have small flowers that generally pack a punch when massed together into a flowerhead - think banksia, waratah or protea itself. In this case the flowerhead is a little more subtle, although the red new growth makes up for this in great measure. There are only a handful of the small flowers below each leaf, and up to dozen or so of these them clumps on any single flowering stem.


All 14 species grown in the Western Cape region and only three are not threatened with extinction. The species photographed here, a few new plantings near the Oak Lawn in Melbourne's Royal Botanic Gardens, is Mimetes cucullatus, the Common Mimetes or Common Pagoda. As you'd expect from its vernacular name, is one of the three.

The genus includes some survivors though. One species, the Silver Pagoda (Mimetes stokoei), was thought to have become extinct when the last plant was killed in 1969. After a fire 30 years later, though, seed stored in the soil germinated and the species sprang to life again two years later.

In fact all but the Common Mimetes release seed that will germinate after fire. Instead, the Common Mimetes has an large rootstock and resprouts after fire. Perhaps for this reason it is described on PlantZAfrica (my favourite South African plant website and source of much of the information here) as 'among the easiest members of the protea family to grow'. It flowers throughout sprinter, sprummer and summer, and often other times as well.

Life can be tough. When it is really tough, we either bunker down and wait for the good times (resprouting) or sacrifice ourselves for future generations (looking after our seeds). Tenuous perhaps, but the best I can do as a reflection on Mimetes imitating life.


*James Joyce, I understand, was one of the first to use a mimetic approach to his writing (he certainly imitates life well in Ulysses) and there is the wonderfully titled, and unread (by me) paper called 'The memesis of metempsychosis in Ulysses'. Metempsychosis being all about transmigration of souls and reincarnation, I not sure I'm up for reading it anyway. 

And just for the record, chapter or episode 3 of Joyce's Ulysses is sometimes called Proteus. The action takes place at Sandymount Strand, on the way back to Dublin from Sandy Cove, where the day starts in Ulysses and where I photographed the local swimming hole (the Forty Foot) on Bloomsday in 2010. Now that's tenuous!

Tuesday, 4 March 2014

Gum-filled teeth, golfballs and telegraph cables


Ten years ago, Stuart Brown of Fortune magazine was having his root canal filled with gutta percha. A few months ago Neville Walsh of the Royal Botanic Gardens Melbourne was doing the same.

As is their wont, the dental guy working in Neville’s mouth struck up a conversation with him while his mouth was full of scaffolding and pointy metal implements. He mentioned that gutta percha was a plant product, and one with an interesting history.

He was right, on both fronts. Stuart Brown explains that gutta percha is the sap of a tree native to South-east Asia called Isonandra gutta (these days we call it Palaquium gutta). It was overharvested at first, leading to destruction of native populations and a collapse of the market. Later, and today, it is grown in plantations in Asia and South America.

According to Wikipedia (a handy if not always impeccable source), gutta percha means ‘percha sap’, after the Malayan common name for the species, Getah Perca. (To confuse things a little, a Northern Australian species that produces nice timber but no toothsome sap, Excoecaria parvifolia, is called the Guttapercha Tree.)

Palaquium is a genus in the Sapotaceae, a plant family providing various foods, medicines, soaps and poisons to us humans. You'll remember the miracle fruit of last year.

Like rubber, gutta percha is an isoprene, but with different chemical bonds making it not as elastic, a better insulator and rather plastic when heated. It started its commercial life as an insulating material for telegraph cables stretching across firstly the English Channel in 1851 and then later across the Atlantic. Unlike previous compounds used for this purpose it wasn’t favoured by marine plants and animals.

It also found its way into golf balls, replacing feathers stuffed inside leather. As well as furniture, jewelry, guns and (according to my impeccable source) the orifices of victims of criminal Wo Fat in the 70s television show Hawai Five-O. Nowadays gutta percha has been replaced by synthetic products (except in quaint nineteenth century reenactments by historically inclined golf enthusiasts, and possibly by some television crims).


Dentistry discovered gutta pecha in the later nineteenth century, firstly for filling cavities and then in 1887, according to Stuart Brown, for stuffing root canals where its plasticity and ability to extrude into distant parts of the canal was ideal. So far, a better product, ‘natural’ or synthetic has yet to be found and the gutta percha industry in 2003 was worth $30-40 million, with most of the US product coming from Brazil.

Yet, endodontists are not entirely happy with gutta percha and Stuart Brown reported on research then to replace it with synthetic product that would be easier to work with and didn’t leak quite as much. A paper published last year by Brazilian researchers confirmed that a polymer called Resolin performed better than gutta percha, although it did depend on the filling technique. Enjoy your gum-filled teeth before they go the way of the gutta percha golf ball.

Image: The plant illustration is from Encyclopedia of Life (published by Leo Shapiro, photographer Franz Eugen Köhler, from Köhler's Medizinal-Pflanzen) - this genus doesn't seem to be represented in the Royal Botanic Gardens Melbourne living collection. The gutta percah golf balls are from the Golf for all Ages! site, and the mouth is my own (the gutta percha is hidden towards the back).

Tuesday, 25 February 2014

Tongue-tingling fuchsia evokes runaway cowboys



Sad that about the only thing I could remember about Bolivia was that it's where Butch Cassidy and the Sundance Kid had their final shootout in the 1969 movie staring Paul Newman and Robert Redford. But that was yesterday.

Today I know there is a Fuchsia growing there, Fuchsia boliviana. It also grows in Peru and Argentina, as well as about 20 or so places around the Royal Botanic Gardens in Melbourne. Ours seem to be a cultivar, 'Alba', differing from the species in having a white rather than red flower tube.

Most of the 100 or so species of fuschia come from central and southern American forests, with just a few scattered across Pacific islands such as New Zealand. While digging around for information on this particular species I rediscovered in my own blog that Tamarillo calls Bolivia home, as well as the lesser known Achacha and Ocha. All of which you can eat.


As you can Fuchsia boliviana, or at least its purple fruits which I gather have been cultivated and sold in markets in South America since the time of the Incas. You can see the fruits swelling at the back of this clump of flowers in our Gardens.

Apparently the fruits taste like a kiwifruit or grape, but not as sweet. A book published in 1961 on the ethnobotany of Peru describes them as having a "sweetish taste" and being "mildly narcotic". Just add sugar perhaps: fuchsia fruits are used occasionally to make jam, although I haven't tried it (making or tasting).

The author, Margaret Towle, says the flowers were also popular with the Incas and may be the source of images that appear in their artwork and ceremonies. Which is not surprising. The flowers are elegant and arresting.

In Melbourne, Fuchsia boliviana is an attractive shrub growing up to a couple of metres tall, doing best with a bit of protection from full sun (in South America it grows at high altitudes, under the forest canopy).


It was back in November when I photographed these flowers, from the garden alongside the nursery between E and F Gate. Although it's said to flower almost all year our Melbourne summer knocked it around a bit and it doesn't look like it will flower again any time soon.

I was hoping I might be able to return about now to find if not more blooms then flowers converted into the purple fruits prized by the Incas. No such luck. Although I walk past one of the plants almost daily, I didn't notice any purple fruits.

I presume the fruits did ripen and were eaten by some lucky local wildlife. The young fruits were certainly swelling back in November. I doubt pollination was a problem. In its home territory various bees and birds pollinate the flowers and although the flower has a very long, narrow tube all the important bits are hanging out the end.


The best I can do is reproduce here a photo from Irene's Website (above). In comparing the Fuchsia boliviana fruit in look and taste to the overripe kiwifruit, 'Irene' says you get a similar tingling of the tongue. If I want that, I can chew the bark of Dinosperma erythrococcum, an Australian native called Tingletongue. But then that species doesn't have any of the romantic associations of a doomed Bolivian shootout.

Tuesday, 18 February 2014

Slime mold hardly dog vomit or scrambled egg


These pink blobs in Melbourne's Royal Botanic Garden are slime molds (or moulds). They are not fungi, or for that matter algae, plants or animals.

'Slime molds' is not what we call a natural group. That is, organisms called slime molds aren't the only descendants of a common ancestor. Natural groups are things like flowering plants, primates and Entwisleiales. Unnatural groups are things like algae, trees and cuddly animals - these are terms of (sometimes great) convenience.

The slime molds can be divided into various convenient, and some cases natural, subgroups. The plasmodial slime molds (or Myxogastria) are microscopic, often swimming (they can have flagella) cells that fuse together to form a great big cell with thousands of nuclei (each one the 'brain' of the single swimming cell). The big cell, the slimy moldy bit, is called the plasmodium. These you can keep calling slime molds.

The cellular slime molds (or Dityostelia) are microscopic non-swimming cells that only every now and then aggregate into a 'slug', called a pseudoplasmodium. Unlike its plasmodial colleagues, the individual slime-mold cells maintain their integrity and the slug is a little like a many-celled organism such as mushroom, rabbit or...slug. They are better treated as 'social amoebae' rather than slime molds.

There are other smaller groups, more or less related to these two. The slime nets (or Labyrinthulomycetes) are these days not to be mentioned in the same sentence (apart from here) as the slime molds. These mostly marine creatures consist of tubes along which cells glide along looking for food. The slime nets are related to, and possibly part of, the Heterokontophyta, which includes diatoms and kelp (algae) and phytophthora (water mold).

All of these organisms produce spores when things get tough. Sometimes the spores are clustered on the top of a stalk, other times in round puff-ball like structures like these (at the end of my forefinger).


This particular slime mold is called Lycogala epidendrum, a plasmodial type. It's growing in a pot of Swainsona in the nursery at Melbourne's Royal Botanic Gardens. The picture at the top of the post was taken by David Robbins, a few weeks before I saw and photographed them in early January.

A few weeks before David Robbins, and Val Stajsic (the Identification Botanist who lived up to and extended his job title by identifying it as Lycogala epidendrum), saw it these fruiting bodies called aethalia, the slime mold would have consisted only of tiny red cells. I think the fruiting body is the entirety of the plasmodium stage in this case.

Those slime molds that form big slimy masses of various kinds - dog vomit, red raspberry, scrambled egg, wolf's milk - can cover up to a square metre or so in some species. They not only spread but move, being able to track down food (bacteria, yeasts and algae) or repel themselves away from something nasty at a rate at least 10 times faster than a plant. Not quite your typical animal speed but fast for a slimy mass I'm sure you'll agree. Our slime mold just stayed where it was, in the pot.



Notes: Information sourced from among other places University of California Museum of Paleontology, The Eumycetozoan Project and an article published in the Proceedings of the National Academy of Sciences of the USA on the origin and evolution of slime molds by Sandra Baldauf and Ford Doolittle. This mention of Doolittle reminds me that a slime mold shouldn't really be part of TalkingPlants (or TalkingAnimals to be fair) but I'm willing to include anything that is rather sluggish and grows in a pot...