Tuesday, 21 April 2015

Chilean pine no puzzle for this monkey

Norfolk Island has one species of araucaria, Araucaria heterophylla (commonly and sensibly called the Norfolk Island Pine) native to its 35 square kilometres. This species is found no-where else in nature, but commonly in seaside and other public plantings.

At about the same latitude on the Australian mainland, and then more rarely further north above Cairns, grows the Bunya Pine, Araucaria bidwillii. Its remaining natural populations in southern Queensland are scattered over an area of about 19,000 square kilometres. It too is relatively common in cultivation although often having to be fenced off when the dropping of its football-sized cones risk serious injury to those walking underneath.

The third Australian species, Hoop Pine, Araucaria cunninghamii, grows naturally in New South Wales and Queensland, as well as in Papua New Guinea which also has a species of its own, Araucaria hunsteinii. There are another two species in South America. The best known is the Monkey Puzzle Tree, Araucaria araucana, or more helpfully sometimes Monkey Tail Tree (the 'puzzle' name refers to how challenging it would be to climb this spiky leaved tree, even for a monkey) from Chile and Argentina. The other is the Paraná or Brazilian Pine, Aracauria angustifolia, of southern Brazil and bits of Argentina and Paraguay.

This accounts for six of the 19 species of araucaria on Earth today.

The other 13 species are restricted to the 19,000 square kilometres of New Caledonia, about 1200 kilometres east of mainland Australia. This is amazing, but today I'm not going to talk about the ridiculously diverse and fascinating flora of New Caledonia, but about South America, where as you know I've just spent a week or two.

In the parks in Buenos Aires (Argentina) and Santiago (Chile) you see plenty of Brazilian and Bunya Pine, but very little of the Monkey Puzzle Tree. In Santiago there are a few young specimens planted in the Jardín Mapulemu which they promised me will grow into towering trees, but the general wisdom is that it's too hot in these cities.

The Monkey Puzzle Tree once formed extensive forests in southern Brazil and Chile, in cooler, high-altitude areas. Today it is under threat of extinction due to previously widespread timber harvesting but there are some beautiful stands in the parks near Pucon in southern Chile. The pictures here are from Huerquehue National Park, about 40 km from Pucon and with a nice view of Villarrica volcano (which erupted in March this year, leading to the evacuation of Pucon) about 50 km away.

According to Kew Gardens, Archibald Menzies introduced the tree into England in 1795, only fifteen years after a Spanish explorer became the first European to see it in South America. Menzies squirreled away some seeds he was served as a dessert, while eating with the Governor of Chile. He sowed the seed while at seed and returned with five plants, one of which grew in Kew Gardens, London, until 1892.  

The common name alludes to the fact that the task of climbing the tree, with its sharp branches tightly clothed with spiny leaves, would puzzle even a monkey.

It was in Kew Gardens I last saw a mature (well, teenager) specimen, on the lawn near the Orangery. What surprised me about it in nature was the trunk, with its plates or large tessellation (I remember the excitement around the Wollemi Pine, a relative in the same plant family, and its coco-pop textured bark)...

...and the cryptogamic flora on those trunks (up high mostly a kind of Usnea, or Old Man's Beard, giving a grey-green colour to its trunks).

Well, that and its striking visage as trees, some of them reputedly 1500-2000 years old, emerged above southern beech (Nothofagus) forest. As we enjoyed the view across a lake that reminded me of south-west Tasmania (although the water was glacial blue rather than tannin tea-coloured) our guide, Gonzalo, completed the experience by offering us seed to eat. Unlike those served to Menzies, ours were boiled and quite dead. 

As we enjoyed our lunch of sandwiches enhanced with Monkey Puzzle Tree 'nuts' another forest of this species was burning a few hundred km away. The species is listed as vulnerable to extinction (not the highest rating but one that means we need to keep an eye on the remaining populations) and it has been declared a 'national monument' in Chile, which seems very fitting. This all means you won't find wall paneling, tables and lamp stands like these in the 1950s designed and built Hotel Antumalal, just out of Picon.

As to seeing one in Australia, I remember a fine specimen in the Blue Mountains Botanic Garden at Mount Tomah, near Sydney, and here in Royal Botanic Gardens Melbourne we have this, with a few (hundred) years growth to come and dutifully worried over by Chris Cole.

Tuesday, 14 April 2015

Un(m) trio de latinoamericanos Jardín(im) Botânicos

Over the next few months I'll intersperse my posts of locally found plants with those I discovered on my recent visit to Latin America. This travel was supported largely by the Charles and Cornelia Good Foundation, to provide the opportunity for me to develop as a botanic garden Director, learn more about world botanic gardens and spread the influence of Melbourne's own.

This first post is quick guide to the three botanic gardens I visited, in Brazil (Rio de Janeiro), Argentina (Buenos Aires) and Chile (Santiago). Later I'll extract intriguing plant species from their collections, or from trips made into a couple of parks and gardens in these countries.

According to all the locals I spoke to, botanic gardens are not as deeply embedded within the cultures of Southern America, or for that matter their historical European connections. Unlike the United Kingdom, North Ameria or Australia, for example, I was told that 'Latins' generally don't have a great love or attraction to plants or nature. They are more interested in human culture it's said. Anyway, these are three botanic gardens trying to change that.

Jardim Botânico do Rio de Janeiro (Brazil)

This 55 ha botanic garden (in a 137 ha property, the rest not open to the public) in Rio de Janeiro was established in 1808, making it the oldest botanic garden in the Southern Hemisphere I think, predating Sydney’s by eight years. There are no trees remaining from that original date but the famous avenue of Imperial Palms (Roystonea oleracea; pictured at top of post) is continually replaced using progeny of the original specimens – the oldest today is probably 100 or so years. Trees (and palms) are the most important part of this botanic garden; in fact they refer to it locally as 'The Arboretum'. There are elderly avenues of mangoes, cloves and those palms. Cannonball trees (Couroupita guianensis) line one path and important tropical crop trees such producing Breadfruit, Jackfruit and Rubber are scattered through the collection.

The garden started as an acclimatisation garden, created by Dom João VI, who fled to Rio in fear of being captured by Napoleon in the early nineteenth century. He secured the site for a gunpowder factory and a place to trial and harden plants from the West Indies. In time it evolved into a botanic garden (for a while being called the Royal Botanical Garden) and was made open to the public in the 1820s. Today it is an impressive collection of tropical species from various ecosystems in Brazil and elsewhere in the world.

The stands of giant bamboo, large amazon lily leaves on the ponds and the exotic flowers and fruits of the tropical trees are all stand outs. One of the signature plants in the 6,000 species collection is the Brazil Tree or Pau-Brazil Tree, Caesalpinia echinata (a genus of legumes well represented in the tropics). The country Brazil (Brasil) is named after this tree, or more accurately after the workers who harvested the wood from these trees, who were called were called Brasilians. (Interestingly, the former name of the region was Pindorama, meaning land of the palms.) The shade house collections, including many epiphytic orchids, are not as impressive as those in the Roberto Burle Marx garden (just out of Rio, which I also lucky enough to visit), but pretty enough. That said, the bromeliad collection (housed in what is called the 'Roberto Burle Marx Glasshouse') while not a stunning landscape display was rich and had great interpretation. Nearby an outdoor landscape of bromeliads has been created from plants saved before an area of Rio de Janeiro was cleared for housing development. A medicinal garden, within the walls of the ammunitions store, is informative and linked to creative displays of laboratory glassware and traditional plant products.

Jardín Botánico Carlos Thays de la Ciudad Autónoma de Buenos Aires (Argentina)

The entire garden is only seven hectares, with about 1,500 species and 12 horticultural staff. Established in 1898, it lies almost midway between the Rio and Santiago gardens in age, but experienced a period of grand neglect between 1930 and 2010. French architect Carlos Thays designed the layout, the broad outline of which remains intact today with some of his tree plantings (many of them too close now that they are mature). Apart from the rudimentary remains of some formal gardens, most plants are organised by geographical region, with an extensive Australian collection of eucalypts and other familiar trees and shrubs. 

The flora of Argentina, and other parts of what is called the Southern Cone (Argentina, Chile and Uruguay), is well represented and the Director Garciela Barreiro is adding to this as she restores the garden. A particularly successful new addition is the butterfly garden, a collection of plants to attract butterflies and caterpillars, such as the Monarchs. While I was there the garden was flittering with butterflies, as well as attracting many other insects and one humming bird. There is a good collection of conifers, including the genus Araucaria with representatives from South America, Australia and New Caledonia (Araucaria bidwillii, the Bunya Pine, is commonly planted in public parks in Buenos Aires). I was impressed to see a large specimen of Chrysophyllum imperiale, a species growing in bothy Sydney's and Melbourne's Royal Botanic Gardens but now extinct in its natural habitat near Rio de Janeiro – I don’t recall seeing a specimen in that city’s botanic garden.

Another new addition, but with a link to the past, is a small crop of Ilex paraguariensis. This plant is the source of the local (non-alcoholic but apparently caffeine-rich) beverage, 'mate', which I'll post on separately. Something even more unusual is the presence of domestic cats, as well as bowls of cat food and water. Cats are so regularly dumped in the garden, volunteers have decided to feed and care for them then offer up for adoption. This is tolerated by the Director.

Jardín Botánico Chagual (Santiago, Chile)

The setting for this very new botanic garden is in equal measure challenging and spectacular, with steep slopes set above the Santiago valley, with the Andes in the distance. Horticulturally it’s an extremely challenging situation due to the dry, clay soils, and the steep slope. Then there is the lack of support, yet, from the local government. With only 9-10 staff, five of them actively involved in horticulture and those without any formal horticultural training, it’s a struggle. At the moment the ‘botanic garden’ consists of an interesting collection of pot-bound plants in a nursery and a few scattered plantings out in the public areas. While technically open to the public now there is no front entrance or welcoming signage, and the interpreted collections are in pots bordering the nursery area. But there is great potential. 

When completed the 44-hectare botanic garden will include plants from Mediterranean regions around the world, but with a strong focus on the local flora (including endangered and medicinal plants). Expect to see extensive displays of Chagual (pronounced ‘Cha-well’, in first picture of the two above), species of the bromeliad genus Puya, of which five of the known nine species are native to central Chili – you might be familiar with the giant flower spikes of Puya berteroniana, with vivid blue-green flowers. There will also be Chilean representatives of various southern hemisphere genera we are used to such as Nothofagus and Araucaria, and displays of the Easter Island endemic Sophora toromiro (which is being introduced, after extinction in the wild, from seed held and grown by our own botanic garden). And of course Chilean Wine Palms (Jubaea chilensis, of more in a later post), which is widely planted in botanic gardens around the world, including a majestic specimen planted on the lawn behind the National Herbarium of Victoria in 1904 by the Government Astronomer, Robert Ellery.

The Royal Botanic Gardens Melbourne formed a partnership with Chagual a decade ago, just five years after it began, sending over Rodger and Gwen Elliot to advise on Australian plantings, and previous Director Phil Moors twice to advise on planning and strategy. My visit was to reconnect and continue that relationship. 

* * *

Tuesday, 7 April 2015

A plant with a twist, nearly missed

It's so easy to miss a quirky flower or fruit in Melbourne's Royal Botanic Gardens. There is just too much going on. You have to always be on the look out for a fleck of colour here or a odd bauble way up there.

Back in early February I discovered this Corkscrew Tree on twitter. It was flowering beside a major path near the Canna Bed, but it wasn't until I tracked back from a tweet to MelbourneDaily that I realised it was in my own (work) backyard.

Nick V. posts occasional, and always well illustrated, posts on MelbourneDaily. His pictures are always great and he does his research. These are my pictures, with only a little more research!

Nick headed his story 'Pretty Deadly', which is a sure way to attract attention. Like lots of plants in the Apocynaceae (think Oleander) the Corkscrew Tree is poisonous in anything but extremely small quantities, and then sometimes medicinal. The PlantzAfrica website lists among its common names Poison Rope, Common Poison Rope and Forest Poison Rope.

I get the poison bit and thought perhaps the length of the unruly shoot heading out of this generally pruned plant (to the top right) might be an indication that its flexible branches are used for rope, albeit of a poisonous kind. In its natural habitat, in the forests of south-eastern Africa, I gather it is a scrambling climber.

My rope theory is supported by a Flowering Plants of Africa synopsis of the species but the genus name Strophanthus means 'twisted-rope flower', because the petals have a jaunty twist, so it may be that the term Rope in the common name references this too. In Australia we call it the Corkscrew Tree, again a reference to the flower. Or sometimes simply Corkscrew Flower.

The genus Strophanthus is widespread in Africa, with a handful of the 38 species in Asia. The various species pop up in herbals and healing websites, usually with strong warnings about the toxicity of the leaves and seeds.

Strophanthin, present in the seed of most species, is a little like digitalis in its action. It can stimulate muscles, like the heart, and it can kill when painted onto arrow tips (a single seed crushed and glued to the end of the arrowhead is enough to increase contractions then seize the prey's heart). Apparently, antitoxins from some species can be used to treat snake bites in the absence of specific anti-venom. Here in Australia though we have good access to anti-venom and it isn't a recommended method.

I was happy just to photograph and observe our species. The blood or red-paint splotch must surely attract the pollinating butterflies into the sexy middle of the flower. The white threads are appendages on the petals rather than the males parts of the flower (the anthers), which are nestled deep inside the flower with the female bits. (If you do tease a flower open you'll notice the real anthers are topped by lovely soft hair, looking very un-anther like.)

Once I'd got past the twisted, blushing flowers I noticed these large, pencil-shaped fruits. When they dry out, feathery seeds are released, carried away by the wind. Strophanthus speciosus was once separated out into its own (single species) genus called Christya because the tuft of hairs at the top of the seed is hardly stalked.

So just another plant, and another story. But I almost missed it!

Tuesday, 31 March 2015

Coriander cure for foul food

You might not recognise these beautiful flowers as those of the coriander plant. And you might not know that coriander can neutralise some of the foulest odours on earth, those arising from a dish served up for Thanksgiving and Christmas dinner. No, not the turkey but the insides of a pig.

I didn't know that boiled or fried (large) hog intestines were a popular festive food for folks in the southern States of the USA. Not that I'm surprised. All the bits and pieces of a dead animal seem to find favour somewhere.

The surprising bit - although not shockingly so having eaten Durian and blue-veined cheeses myself - is that chitlins, as they are called, have a 'notoriously foul odour...reminiscent of the waste material that once filled the intestine'. Fecal and sewage are words you find in descriptive passages (so to speak) about chitlins.

To get through the cooking, and eating, of this foul smelling food our American friends (and those in other countries such as Central America and Asia where it also makes it's way to the dinner table) look for ways to mask the odour. I know, it's tempting to suggest that something else be eaten instead but us humans do the darndest things.

The herb of choice for many stinky foods is Coriander (Coriandrum sativum), in the carrot family. We think of Coriander as a kind of weird parsley (in fact it is sometimes called Chinese Parsley) that makes our dishes taste more Asian and less European, or in seed form as the bulky part of our curry mix. It's sometimes added to medicines to 'correct' their flavour. That said, some people find the odour and taste of Coriander itself, whether leaf or seed, a little off-putting.

The list of medicinal uses apart from flavour correction is long: dyspepsia, loss of appetite, convulsions, insomnia, anxiety, diabetes and more generally killing bacteria. We use the fresh leaves (sometimes called Cilantro) and dried fruits (which we call Coriander seed) quite differently, and the active chemicals, and flavours, vary in different parts of the plant and through the development of the fruits.

I was diverted by all this recently when our crop 'went to seed' and I had a chance to enjoy not only some attractive flowers but also some differently sculpted leaves. As you can see the leaflets (below) narrow up on the flowering stem and look quite different to the typical culinary ones above. Lots of plants do this kind of thing but it's cute to observe.

Unfortunately although it went to seed it didn't make it to fruiting stage (probably due to a few missed waterings and other abuse). I did get to enjoy the flowers, though, illustrated at the top of this post. They are grouped into clusters we call umbels and each one has fully furled petals pointing out from the centre and shrunken petals pointing inward. Again, cute.

So much for my petty pleasures. What about those stinky intestines in the USA? A research group in Japan lead by Yasuyoshi Hayata found that indeed Coriander worked with Chitlins. They then went further and isolated the odour-eating agent itself, a chemical with a 'flowery fragrance' called (E,E)-2,4-Undecadienal.

Less than a drop of this chemical in our Chitlin should do the trick. It works at a concentration of 10 parts per billion or, as the researchers helpfully convert it, 10 drops per Olympic-size swimming pool. Now that's a lot of intestine.

Tuesday, 24 March 2015

Sexy persimmon

A few years ago Jane Edmudson on the ABC’s Gardening Australia described some persimmons as suitable for eating like an apple. Others, she said, are almost inedible due to their astringency. There are some 1000 cultivars so you have plenty to choose from.

As you’d expect if you read my recent post about how the Globe Artichoke can change our sensation of sweetness, it’s the phenolics in persimmons that pucker your mouth. In this case, mostly tannins.

Apart from causing mouth puckering, the tannins in the fruit of Diospyros kaki, the persimmon, can be used for waterproofing, food preservation and dyeing. The fruit and leaves also have some potential medicinal uses, currently under investigation: I gather you might already find persimmon extract in 'athlete's foot socks and soap'.

As I discovered in my local park, where a single persimmon tree has been placed among a collection of other edible-fruit trees, the flowers are either male or female. Although on the same plant in this specimen, they can sometimes male on one plant and female on another.

The females (above) have the green, leathery, almost-Elizabethan collar that ends up ornamenting the fruit (see top of post). The male flowers (below) are pretty insignificant in comparison, and look like they might just be spent blooms.

Varieties that produce fruit without seed don’t need to be pollinated, but fully loaded fruits need male flowers in the vicinity. In US orchards farmers grow trees in a ratio of eight female to one male, although I did read that trees can change their sexual orientation from year to year, which if true would make this tricky!

So I tracked down some authoritative advice from the University of California in Davis (USA) on, as they put it, 'what makes a persimmon a boy or a girl'...

One in 20 plant species have flowers on a single sex. It's a great way to mix up genes during pollination, making sure flowers don't pollinate themselves or, if the flowers are on separate plants, don't pollinate with flowers on the same plant. There are other ways to stop this happening, but dioecy, as it's called when single-sexed flowers are on separate plants, is a good way.

The scientists at University of California say persimon plants are either male or female, which makes my parkland plant a little odd. My plant would be described as monoecious meaning that while it has single-sex flowers (either male or female) these are born on the same plant. A dioecious plants has only male, or only female, flowers.

This I remember from Botany 101, or whatever we called it, although the terminology gets a little confusing when transferred to algae, where I drifted later in my studies...

So this, my parkland plant, is monoecious and my American university colleagues say persimons are dioecious? I needed to read more closely... These guys were working on a different species of persimmon, Diospyros lotus, sometimes called the Date Persimmon or Lilac Persimmon. It has smaller fruits and, it seems, a slightly different sex life.

The researchers were looking for the gene that coded for maleness or femaleness. That is, what makes it a boy or a girl persimmon? They found a gene system they call OGI-MeGI: ogi is Japanese for male tree, megi for a female tree. Their next task is to see if this kind of system is universal in all plants, and to see if they can introduce dioecy into the 95% of plants that don't have unisexual flowers on separate plants to help with breeding and plant health.

Meanwhile, back in the park, I'm going to have to track this plant to see if it keeps producing flowers of both sex (monoecious) or switches to only one sex (dioecious). I'll get back to you in a few years, perhaps.

Images: The flowers and young tree are from the park near where I live, photographed in December 2014, and the fruit from a Grow Organic website.

Tuesday, 17 March 2015

Puka might go to pot

This is the Puka, or Meryta sinclairii, a species growing naturally only on Three Kings islands off the far north of the North Island of New Zealand. These islands are at a latitude of 34 degrees south, pretty much the same as Sydney.

A New Zealand species with subtropical attitude, it is dotted all over Melbourne's Royal Botanic Gardens. And as you'd expect from something in the ivy family (Araliaceae), it's not about the flowers. Nineteenth century Director William Guilfoyle knew this. The Puka was part of his plan to contrast leaves of varying shape, size, texture and colour.

As pointed out in the booklet A Gallery of Plants (1992) by Ros Semler, this species is a distinctive element in the garden beds around the Nymphaea Lily Lake, all of which continue to display Guilfoyle's design intent in regard to diverse foilage. Meryta sinclairii rates a mention in most books on Melbourne's Royal Botanic Gardens.

The leaves are chunky and at first blush a little like those of some mangroves, such as Clusia. In its native habitat it grows mostly in sheltered, moist valleys but it seems to do well out in the open and with minimal watering, albeit with a little leaf burn off in the Melbourne summer (this next picture, and others from the Royal Botanic Gardens, were taken in mid-January).

Our plants flower, although I don't know how regularly. There are separate male and female flowers, both nondescript, with the female flowers followed by ivy-like berries. I found some flower buds (in January) on a bush on the Ornamental Lake side of what we call the Central Lawn, but only a few remaining fruit. Here is a picture of those precient buds, followed by an picture of young fruit on a specimen growing in New Zealand, photographed by Warren Brewer (©)

According to the online Flora of New Zealand, Puka was first collected for science from a single plant growing at Paparaumu, in the Whangaruru Harbour, about 150 km north of Auckland. The soon to become Director of Kew Gardens in London, Sir Joseph Hooker, described it as a new species in 1852, in a genus called Botryodendrum. That genus has since been split and subsumed, with most species relegated to Meryta which now has about 28 species.

The Wikipedia entry has a ring of authenticity about it so I'll chance repeating this tale. William Colenso, the first European to find the specimen at Whangururu Bay was frustrated in his attempts to collect flowers and fruits - he visited regularly over a number of years but found none. Both he and the Colonial Secretary Andrew Sinclair sent leafy stems to Sir Joseph who eventually got fertile material, off the same tree, from a William Mair.

From the same source I can report that the Puka has the largest entire (that is, not divided into smaller leaflets) of any New Zealand plant. Sounds about right, and supported by a comment reiterated by Ross Beever in his paper on the natural distribution of the species, that the Puka is the only 'true macrophyll' in the New Zealand flora.

Most of the 28 species of Meryta are found in the tropics and subtropics, with a whopping 11 found in, and only in, New Caledonia (a lot, but two fewer than there are Araucaria species there...). There are no species native to mainland Australia or mainland New Zealand - just the one species, the Puka, on the Three Kings Islands (and introduced onto the nearby Hen and Chicken Islands) and two (Meryta angustifolia, Meryta latifolia) on the more-or-less-self-governed Australian territory of Norfolk Island.

Meryta sinclairii is uncommon and at risk of extinction in its natural habitat. The New Zealand Plant Conservation Network - an at all times thoroughly reliable source of information - note that the remnant natural populations are under threat from marijuana growers who like using remote islands to grow their crops. It's not that the ganja outcompetes the puka, but the illegal farmers often bring with them deadly (to the Puka) fungal pathogens.

Tuesday, 10 March 2015

Titan Arum's honorary flower

When the Titan Arum blooms - as it does regularly in glasshouses all over the world these days - botanic gardens' spokesfolk, such as me, employ all kinds of linguistic contortions to describe the structure of the 'flower'. This gigantic thing is a collection of tiny male and female flowers, with some fancy trimmings.

As most people now know, when the swollen green 'flower-bud' opens, a purple pleated skirt is unfurled, exposing the lower half of a yellow banana-shaped object that seems to have the texture of chamois leather. A powerful and rank smell rises from deep within the now skirted banana, attracting in its native land of Sumatera various flies and beetles. In botanic garden glasshouses, the descriptively named Amorphophallus titanum attracts people, as you can see here in Sydney Royal Botanic Garden's Tropical House a few year back.

The object of desire is either the world's biggest cluster-of-flowers or the biggest unbranched-inflorescence (an inflorescence being a collection of flowers and associated bits and pieces). For the botanically inexperienced, or perhaps willfully radical as I'll argue, it's the world's largest flower (but see also Rafflesia).

This is our most recent bloom in Melbourne's Royal Botanic Gardens Tropical Glasshouse. It's the third time a Titan Arum has flowered for us, and the second time for this particular tuber (the first flower was in January 2013, a month after its Christmas flowering sibling). Our tubers came from Sydney's Royal Botanic Garden and their plants started as seed collected by David Attenborough and Wilbert Hetterscheid in Sumatera in 1993. The tip of the banana was 233 cm above the ground late yesterday; impressive, and closing in on the biggest recorded in Australia (Cairns had one at 238 cm in 2014), but well short of the record of 290 cm for a plant in cultivation. We expect the thing to open fully in the next few days, perhaps putting on a few extra centimetres on the way...

But what do we call this huge and impressive infrastructure, home to thousands of tiny flowers, or florets as we sometimes call small flowers of this kind? Each one consists of either a single bottle-shaped pistil (this is the stripped away female part of a female flower, including the ovary in the bottom of the bottle, a stalk called a style and a sticky blob on top called a stigma) or a single stamen (in this case a spherical sack of pollen).

None of these flowers/florets are garnished with petals. The pistils (female 'flowers') are in neat rows at the bottom and fire off together - sorry, they become receptive all at the same time. The stamens (all that there is of the male 'flowers') are packed in at the top and release pollen together. So although technically the skirted banana structure is a collection of single-sex flowers with some very fancy accoutrements, if the whole thing looks like a flower, behaves like a flower and smells like a...dead possum...let's call it a flower.

I would argue, following the lead of an expert in this family, Dr Alistair Hay, that the floral bits are so reduced as to be equivalent to organs within a larger flower and the skirt (spathe) and banana (spadix) work in the way any other flower does in attracting pollinators to the receptive parts of the flower(s). In fact the Kew Plant Glossary helpfully describes a flower as 'an axis bearing one or more pistils or one or more stamens, often with parts to make it more functional or more attractive to pollinators'.

Now of course you could argue the same way for any inflorescence or collection of flowers but, I would suggest, rarely as coherently as with the Titan Arum bloom. It certain teeters on the edge of being a flower or an inflorescence.

Maybe the solution is to give this spectacular and fascinating structure honorary flower status. I can see parallels with the debate over Pluto's planetary rank although I'm not sure it helps my botanical case to read that Pluto may soon return to full planet status after having to endure the floret-like moniker of 'dwarf planet' for the last nine years. That aside, the 'largest unbranched inflorescence in the world' is just lame.

Images: The unopened Melbourne flower, with close-up of skirt/spathe at the top, come from a stock of images taken by David Robbins, Robyn Merrett and me. The carved plant and close-ups of pistils and stamens, plus the following picture of a spent flower with its inside-out skirt looking like a breezy coiffure, I took in 2007 at the botanic garden (Keban Raya) in Cibodas, Indonesia. The open flower (!) above, with a visiting man, is from Sydney in 2008.

Feedback: Dr Phil Garnock-Jones from New Zealand suggests the term blossom. He says in a tweet (10 March 2015): "Excellent. I'd call it world's biggest blossom. Many flowers, 1 blossom; cf. an iris, with one flower, 3 blossoms" Has some merit.

And further information?: See and hear me talking about the flowering of the Titan Arum in Melbourne on 13 March 2015, with excepts from this post about whether it's a flower or group of flowers, on RN website.

Tuesday, 3 March 2015

Begging for begonias

I shouldn't say beg, it was more like a coax and persuade maneouvre (but that doesn't alliterate as well). Back in December members of the Melbourne Begonia Society encouraged me, as they should, to grow more begonias in the Royal Botanic Gardens.

I was speaking to them about plans for the Melbourne and Cranbourne sites, with a glancing mention of begonias. Apart from their regular displays they prepared a selection of the species William Guilfoyle was growing in the Royal Botanic Gardens in 1883, and presented me with a list of the same.

I was also gifted a photo album including images of everything displayed, plus a few missing species to show me the beauty and breadth of Guilfoyle's collection. On that front, I didn't take much convincing. Begonia boliviensis (sometimes called 'Begonia boliviana' in horticulture*), the species I've used to illustrate this post, is just one of the colourful and sensuous plants on the list. 

And a decade ago, after a some initial hesitancy I became a big supporter of the begonia beds at Sydney's Royal Botanic Garden, approving the expansion by Peter Sharp and his volunteers (supported by Paul Nicholson and other staff) into a second bed (photographed here at its opening in 2007).

In my talk I mentioned the possibility of a new glasshouse at the Melbourne site, the prefect place for begonias in Melbourne. Some grow outside, like the Begonia boliviensis photographed near my front entrance at home, but many more would grow under glass.

I'm surprised I haven't posted anything about begonias yet. As compensation, let me give you some fast facts from my friend Peter Sharp's lovely book, Down to Earth with Begonias.

There are around 1500 species of Begonia, and undoubtedly more to be discovered and described, so I needn't try to grow them all. They are divided up into cane-like, shrub-like, rhizomatous, semperflorens, trailing-scandent, thick-stemmed, rex and tuberous. It's beyond this post to explain the intricacies of begonia classification but for most the names are relatively self explanatory.

The rex bogonias, are perhaps not, and they are all cultivars of one species, Begonia rex, a rhizomatous species (i.e. spreading by underground stem - a rhizome) from the state of Assam in India. The wild species has green leaves with silver banding, I think, but as I saw in the extensive display in Bentleigh, the cultivars now grown have leaves of green to grey to deepest claret and purple. The leaf colour range has been compared with precious metals, and the texture with exotic fabrics.

We grew a couple of rex begonias in our front garden in Sydney, under a tree, where they more or less thrived. Here in Melbourne you'd need a glasshouse, or fish tank.

You can grow quite a few begonias outdoors in Sydney but further south (and up the mountains) it's often best to grow them in pots and protect them from frosts and very cold winters. That said, here in Melbourne the climate may be coming more conducive to growing begonias outdoors.

The best known begonias are probably the tuberous ones bred to produce big blousy flowers, of the kind you might find in the Ballarat Botanical Gardens. These you will find grown and displayed in a glasshouse.

What all begonias share are asymmetrical leaves, as in this picture of the (non-rex) Begonia boliviensis I took home from the meeting in Bentleigh.

In addition to being one of the species grown by Guilfoyle it is also from Bolivia, so I can add it to my Talking Plants list of plants from that oddly romantic country. It's a tuberous species from the cold peaks of the Andes, but happily adapts to gardens in Sydney and Melbourne, producing lovely summer flowers.

Begonias have either male or female flowers, both on the same plant, and as you can see the male flowers are quite open in this species so you can see the pretty anthers ready to release their pollen.

For now the pot sits at my front door. A reminder for when we build a glasshouse at the Royal Botanic Gardens: remember Guilfoyle, Bolivia and...oh, yes...begonias.

*Thanks Peter Moonlight for advice on nomenclature. And look out for a full census of Begonia species, coming soon according to Peter! 

Tuesday, 24 February 2015

Misplaced (and edible) hat plant

It takes six leaves from the Panama Hat Plant to make a Panama Hat. The leaves must be young and most commonly they will come from the country of Ecuador. Never or rarely, I gather, from Panama, where the hats were first traded in the nineteenth century.

The Panama Hat Plant looks like a palm. Indeed it is sometimes called the Jipijapa Palm, after one of the Ecuadorian towns that makes the hats. But it's not a palm. Botanists have always know that. In fact these days we consider it even less of one!

Carludovica palmata has always had its own family, Cyclanthaceae, but this used to be tucked in near the palm family Arecaceae, albeit each within its own order (Cyclanthales and Arecales). The Pandanas family, Pandanaceae, used to be thereabouts, again in its own order (Pandanales).

Nowadays our Panama Hat Plant is included within the Pandanales, closer to Pandanas but distant now from the true palms which are clustered elsewhere in the family tree with grasses, gingers and the water hyacinth (in a group called the Commelinids).

To look at though, the fronds look very palm-like. The one-metre wide leaves are fan-shaped, divided into three to five segments, with each segment further divided towards the tips.Unlike all fan palms, however, it doesn't produce a trunk.

The flowers arise from the base of the plant, on a stalk and grouped in a cylindrical 'spike'. As with cycads, an very unrelated group of plants, weevils pollinate the flowers.

The Panama Hat Plant is a tropical species, growing naturally from Mexico to Bolivia, but more commonly in Ecuador. In Australia it grows outdoors in Sydney and Brisbane botanic gardens, but apparently not here in Melbourne. There are three other species in the genus Carludovica, all with similar horticultural requirements.

Apart from spiffing hats, the leaves are used for 'matting, curtains, roofing, baskets, cigar-cases, purses, fly swatters and brooms'. In fact anything that needs a tough, weavable fibre, including mammal and fish traps.

In Ecuador the base of the unopened leaf base tastes similar, apparently, to a palm heart. This may be a more sustainable way to satiate that particular food fetish given that extracting the heart - the growing point - of a palm kills it.

I just need to wait until this specimen on a colleague's windowsill matures a little, then creep in and do some (sustainable) harvesting.

Image: a photo by Lynda of me with my then new Panama Hat, in London in 2012. The window sill seedling is from the office of Frank Udovicic, at the Royal Botanic Gardens Melbourne, who drew this plant to my attention. The picture of the mature plant is by Bill Baker, from Royal Botanic Gardens Kew, taken inside the Palm House at Kew Gardens by the looks of it.

Tuesday, 17 February 2015

Wiping the glaucous sheen off a Pig's Ear

In early January I kayaked past this plant spreading up, or down, the banks of the Yarra River. Then a little later in the same day, walked past it in jutting from a rock wall, leaves sheening in the brilliant midday summer sun.

It's not a plant you can kayak or walk past easily, particularly when in flower. Cotyledon orbiculata, more commonly called Pig's Ear, is grey with a glaucous sheen, almost all over. The exceptions are the edges of the leaves, which are red, and the inside of the flowers, which in this case are orange to appeal to sunbirds.

Pig's Ear flowers mostly in winter but where there is more winter rainfall, such as the Western Cape (and here in Melbourne), in midsummer. Presumably the African sunbirds know when to be active.

According to Shireen Harris on the PlantzAfrica site, there are 10 species of Cotyledon, a genus name based on the Greek work kotyledon meaning cup-shaped hollow (and also used for what are called the seed-leaves of most flowering plants, the cotyledons).

The leaves of most species, including Cotyledon orbiculata, are cotyledon-like in shape.

The waxy white coating reflects the sun's heat, to prevent overheating and water loss. In low light, little wax is produced, in high light (such as on this rock wall), lots. When fully coated, up to 50% of the sunlight reaching the plant surface can be reflected and water loss reduced.

If you remove the coating, as I did here with my finger, it will take about two weeks to start returning again on that leaf. The waxy deposits are formed inside the leaf cells and exuded to the outside during growth and after injury. It seems that the route to the surface, and the means of production, do not shut down once the leaf is mature.

(I did a slightly more thorough test  on a smaller plant we are growing at home, wiping strips from two differently aged leaves to see what would happen. After two weeks a light cover of wax had returned on both, and now, just over six weeks later, the coating is thick enough to make the strip look grey rather than green, It's still noticeable though and I wonder if it ever completely recovers its full coating.)

I doubt that in the Australian summer my interference will cause the plant, or even this leaf, to die (the cuticle, a more important waxy-outer-layer on nearly all leaves, did survive my vandalism), but is a shame to do it more often than you need to in the interests of curiosity. If for no other reason, it detracts from the beauty of the plant as a whole.

In their southern African homeland, in rocky outcrops, the plant may well be more finely tuned. One poorly performing leaf could be the difference between living and flowering, or death. Perhaps. 

For me now, there are those complex feelings after you have done some thing you really shouldn't have. I know this leaf will recover its wax but will it be in time to survive the summer? I'm not sure if it matters, given the small surface I scraped, but I do add it (along with memories of insects I've squashed, birthdays I've forgotten and chances of selfless assistance to others) to my life-time load of guilt.

But then, in Australia Pig's Ear has escaped from gardens and is spreading through bushland areas, such as the Yarra River verge near my home. If I were to think instead about the potential of this plant to jump the garden fence and spread further into native vegetation, displacing indigenous plants and animals, I could convince myself this was a (very) small contribution to conserving Australia's biodiversity.

But that would be stretching things a little (a lot). And unfair to my neighbour's garden.

Images: all from the plants growing out of the rock wall in a nearby street.