Tuesday, 17 October 2017

Small compensation for unfulfilled Chinese ginkgo quest



Last year I had to cancel at the last minute a trip to Shanghai, where I was going to attend a meeting at the Chenshan Botanical Garden. As part of that trip I had hoped to visit one of the two possibly natural – that is, not cultivated by human – populations of Ginkgo biloba, the Maidenhair Tree, near Tianmu Mountain.

Ginkgo, as most people call it (with a soft first 'g' in China and a hard first 'g' in Australia), is a single species with a deep evolutionary history. It is the remaining member of a group of organisms sitting alongside conifers, cycads and flowering plants, but belonging to none of those groups. It looks like a flowering plant but has motile sperm rather than pollen (more like ferns, cycads and conifers), carried by the wind and needing to land of a drop of moisture to fertilise the female ovule. The ‘fruit’ contains a seed inside a hard outer coating, all within a yellow and stinky fleshy layer.

Reading further on the natural distribution of the ginkgo, including Peter Crane’s monograph on the species called Ginkgo: The Tree That Time Forgot, I discovered that the more likely purely natural population – and there is considerable debate – is to be found in the Jinfo Mountain area near Chongqing. These trees generate from seed and there is more genetic diversity here than anywhere else in China.

And so last week it was with great anticipation I joined the field trip associated with the Chinese Association of Botanic Gardens meeting in Chongqing to Jinfoshan, the Jinfo Mountain. I was in Chongqing as a guest of the Nanshan Botanical Garden, with whom I signed an MoU for cooperation with the Royal Botanic Gardens Victoria. Yet again I was fortuitously placed to visit this fascinating plant in its home territory.

Sadly the weather, and my ability to communicate in Chinese, let me down.


As you can see, the weather was what we describe in Australia as ‘foul’. The entire mountain was enveloped in mist and a gentle to steady rain persisted for the entire time we walked along the summit paths.

It seems I was probably nowhere near to where to the ginkgo grow anyway, so hail or shine I would have not have achieved my goal. The ginkgo grows in a band around the mountain at 470-1,500 metres above sea level. We were wandering around in the mist at 2,100 metres above sea level (about the same height as Australia’s tallest peak, Mount Kosciuszko).

Of course, this being China there are some planted trees here and there, including here, not far from the start of the cable car to the summit, near to the welcoming sign at the top of this post. This may be as close as I get to a ginkgo in its natural habitat...


There are, according to the abstract of a paper by Li Jianwn from Beijing and his colleagues from the Medicinal Botanical Institute of Chongqing City (which I think may be different to the Chongqing Institute of Medicinal Plant Cultivation which I visited on the way to the mountain), 300 or so very old ginkgo trees in the area, at least 10 thought to be over a thousand years old. The oldest - called Ginkgo Empress – is estimated at 2,500 years and has a girth of 35 metres.

So, no naturally growing ginkgo for me, yet. On the return trip we stopped for dinner at a reconstructed village of the local ‘ethnic minority’. There we saw planted ginkgo, and also many penjing (bonsai) specimens, including various leaf-shape cultivars.


I read on a tourist website that ‘when sunshine falls on [Jinfo Mountain], it looks like a giant Buddha shining with boundless golden radiance, hence the name, which literally means Golden Buddha Mountain’, and that ‘the Golden Turtle Facing Sun Platform in the north’, which we visited, ‘is a mountain edge looking like a golden turtle in the light of the sun’. On my visit there was, sadly, no sunshine and therefore no visage of Buddha or a turtle. We did see the large natural caves, and through the mist a few local plant species.

No trip is ever wasted and I’m sure there is aphorism around leaving some things in life not experienced. In fact I expect the Chinese have a way of saying it quite pithily. But still, I hope to one day try again.

Tuesday, 10 October 2017

Giant sea leaves near the lake


"With me tonight, to explain why this giant-leafed plant is almost incorruptible, is Green's spokesperson Ms Grandleaf Sea Grape...".

OK, not quite up the standard of our local television (ABC TV) darling Shaun Micallef, but the common name for Coccoloba pubescens - yes, Grandleaf Sea Grape - did set my mind wandering in this direction. Or was it to Middle Kingdom?

Back in Victoria, Australia, I doubt you will find this species in conversation or in reality. We don't grow this, or indeed any of its kind (Coccoloba) here in the Royal Botanic Gardens Victoria. We do grow other members of the buckwheat family, Polygonaceae, including a few I've blogged on here such as St Catherine's Lace and the Centipede Plant. We also employ one of the world's leading experts on the family, Dr Tanja Schuster.


Grandleaf Sea Grape, or Eve's Umbrella, though, is a plant I only recall seeing once, tucked inside the entrance of this glasshouse in Geneva's botanic garden, Conservatoire et Jardin Botaniques Genève. That's Geneva, Switzerland, is on the banks of Lac Léman but no where near the sea.


There are more than 150 species of Coccoloba, many of them producing clusters of grape-like fruits and quite a few growing by the coast. Hence Sea Grape, a common name applied to various species of Coccoloba. Other local names for this group of species stick with the marine viticulture theme: e.g. Little Beach Grape, Beach Grape Tree and Edge-of-sea Raisin Tree. Less obviously, some species are called Pigeon Wood, Big Potato and White Big Bed.


Nearly all Coccoloba species are from tropical America, with Coccoloba pubscens - our Grandleaf Sea Grape - native to Mexico, Guyana and the West Indies. Fittingly, it seems to have the biggest leaves in the genus, often half a metre wide and sometime bigger. The juvenile form of the plant, which is probably all we'll see in glasshouses, is larger leaved.

The eighteenth century Dutch botanist, Nikolaus von Jacquin, described the mature tree as inelegant but others focus on the beauty, or at least the function, within. The wood is said to be 'almost incorruptible' and when buried beneath the ground - as footing for fence posts for example - can become 'hard as stone'.

Like most of the buckwheat family, the Grandleaf Sea Grape has a distinctive sheath (an ocrea or ochrea) wrapped around the stem, extending upwards from where the leaf arises an. In the close-up below you can see blackish dry flaps which are part of this sheath.


While not in our glasshouses (yet), the Grandleaf Sea Grape has been grown in the conservatories of the UK since 1590, although not flowering until 1832. At that time, due to the 'bad condition of the hothouse' plants did not fruit or set seed.

Tuesday, 3 October 2017

Well hung orchids give Turkish ice-cream its stretch


They say you can tow a car with a rope of the elastic ice-cream made from orchid tubers. But then they say a lot of things.

This particular achievement was assigned to the 'legend' category by The Sunday Age restaurant critic Dani Valent in her recent review (20 August 2017) of a new Turkish ice-cream stop in Northcote called Cuppa Turca.

Turkey is the place for tough and stretchy ice-cream (dondurma), traditionally elasticised with an extract from the tubers of orchids called salep (or sometimes Sahlep or sahlab). As I mentioned in passing last year, the underground storage and over-wintering part of some Orchis species are ground into a flour which is included in drinks and sweet foods.


It seems a cup of salep was popular in the Ottoman Empire, making its way later to England in the 17th and 18th centuries, where it was called saloop. But, as you might have guessed, relying on the rather small tubers of a not particularly common plant has its consequences. In Turkey wild orchid populations have suffered through over harvesting and the product is now banned for export from that region.

In their mildly indulgent The Book of Orchids, Mark Chase, Maarten Christenhusz and Tom Mirenda state that all ground orchids in many parts of Turkey are becoming rare due to unsustainable harvesting for salep. To meet the demand within Turkey, collecting has extended into neighbouring countries with potentially similar results.

According to Wikipedia, the Romans also partook of saloop, preferring to call it satyrion and priapiscus, a reflection of its presumed aphrodisiacal properties. I'm guessing this has a bit to do with a pair of tubers sometimes looking like testicles, which the Greeks called orckhis (hence Orchis and orchids).


Today though, orchids and their testicles are in short supply. The new ice-creamery in Northcote uses a salep substitute, 'a secret recipe that replicates the original'. The product is 'stretchy and smooth and melts very slowly, just like the real thing'.

So what about the real thing, these orchid tubers. The Australasian Native Orchid Society packages up the excess tubers produced from cultivated plants, distributing them to members so they can grow their own.


Not all orchids have tubers, or tuberoids as they are sometimes called, but most Victorian species do. In fact of the nearly 400 species of orchid in Victoria, all but a handful produce tubers or at least fleshy underground roots of some kind. Those that don't are the larger rock and tree orchids.

Southern Australia is definitely the place to go for tuberous orchids. Not that I'm saying there is a potential salep market to be had. Far from it. Many of these species are rare and threatened, and all are protected against collecting on public land. But it makes you think, of ice-cream and other things.


Images: A couple of local tuberous orchids from Victoria (the Spotted Sun Orchid, Thelymitra ixioides at the top; a spider orchid, Caladenia valida, above; and protected by my son Jerome a few decades ago, the Wallflower or Donkey Orchid, Diuris orientalis) plus from the web an image of Orchis ustulus, one of the species harvested for salep and illustrating a pair of tubers, and a tourist site photograph of Turkish dondurma.

Tuesday, 26 September 2017

Navelwort gazing at Spanish walls


It took me a while to track down the name of this Umbilicus rupestris. It should have been easy. The the species name means growing on or among rocks, which it does, and 'umbilicus' means navel, and is often used in botany to refer to roundish, saucer-like leaves (as you can see in the next picture).


So it's a helpful botanical name. Common names include Navelwort and Penny Pies. Navelwort is again a reference to the leaf shape, with wort being a general term for a plant, particularly one used for medicine or food. Penny Pies, or even Wall Pennywort, presumably also refer to the succulent leaves which might look a bit like small meat (or fruit) pie.

This is a fleshy plant, in leaf and flower, and so fits nicely in the family Crassulaceae along with better known succulents such as Crassula, Echeveria and Kalanchoe. Having the capacity to hold some extra water inside the plant would certainly be an advantage when you live a long way from ground water.

My plants are from Spain, on walls and church parapets. This is the view from the parapet supporting the plant at the top of this post, in the town of Ronda.


The flora of buildings is an intriguing one and hardly done justice here, but I'll a few more sightings from my recent travels in southern Europe. This next one is is Sarcocapnos, probably Sarcocapnos enneaphylla, another rock wall plant with saucer-shaped leaves. Presumably this leaf shape is a help in gathering and channeling water to roots jammed into a rather dry crevice.


Sarcocapnos is a close relative of a more familiar group of plants, the Fumitories, often weedy in Australia. I found one of them at the edge of the same church roof as the Navelwort. I’m calling it Fumaria agraria.


Although succulence and scooped leaves might be helpful, you find plants of all shapes and sizes, and from many different families, on the stones.This next one is the Cut-leaved Valerian, Centranthus calcitrapa, a relative of the honeysuckle. (There are also some succulents growing with it, not in flower.)



I thought at first the species name was nod to this plants chalky, calcium-rich substrate, limestone. In fact, a calcitrapa is a four-pronged device laid on roads to stop horses, people or in more modern time vehicles with pneumatic tires. It is better known today as a caltrop. There is a prickly genus of thistles with this name, but in our case I can't see the allusion.

This one is, I think, a Snapdragon of some kind - a species of Antirrhinum. It was up high, among the saints, so well out of my reach.  


The showiest plant I saw on a wall was Capparis spinosa, the Caper BushCapparis is one of those plant groups where I have a blind spot. I see it every few years but can never remember what it is. Thankfully Jana Bate, a well trained horticultural teacher from TAFE Ryde in Sydney, was on hand to 'remind me' of this one.


Other wall-dwelling plants destined for bigger things, like this edible FigFicus carica.


But to finish, not all rock and stone loving plants are adventitious. These wall-hugging creepers (cultivars of Ivy; Hedera helix) were of course very deliberately planted in their concrete pots, but now very much 'own' the stonework.



Tuesday, 19 September 2017

Cracking the Saxifraga crust


Let loose into the rock garden at La Thomasia, the alpine annexe of Musée et jardins botaniques cantonaux in Switzerland, it was difficult to stay tuned to the expert commentary with so many flowers to peer at and photograph. The saxifrages particularly caught my eye but I did pick up a mention of them being an 'air conditioning plant' ... or maybe an 'air conditioned plant'.


I didn't catch the whole story but I gather the white crust on the surface of Saxifraga leaves are in some way providing air conditioning for the plant. That was back in June. A few weeks later I read a brief note in the Royal Horticultural Society's magazine The Garden about a new microscopy technique revealing previously unseen detail of the cells that form this crust.

And so to the source of the story, the University Botanic Gardens at Cambridge. As the University puts it, 'the tight hummocks and large colourful flowers of many saxifrages have captivated gardeners for centuries'. And there are many, 440 in the genus Saxifraga and another couple of hundred in its family, Saxifragaceae. Mostly they grow in cold places, towards the North Pole or up a mountain, and among rocks. The location of La Thomasia, near Bex, suits many of them.


I was surprised to read that the name 'saxifraga' - Latin for ‘stone-breaker’- doesn't refer to what they do in nature but to their historical use for treating urinary stones. But that's not why I'm posting pictures from La Thomasia. It's all about those crystals.


First let's tell you what you are looking at in my pictures. The species seems to be Saxifraga callosa, although labelled in La Thomasia as Saxifraga lantoscana. I see there are cultivars of Saxifraga callosa in the trade under the name 'Lantoscana Limelight', presumably derived from what used to be called species or variety lantoscana from the 'Maritime Alps'.


This isn't the species studied by the Cambridge botanists but the white crust is there, as you can see. The first scientific report of these structures in Saxifraga was in 1890 but it took another 40 years for confirmation that this coating is found in most species of Saxifraga.

The Cambridge team chose Saxifraga cochlearis because the hydathodes, the structures in the leaf that exude the crusty material, progress from small at the base of the leaf to a 'volcano-type structure that spews out of the crust' at the leaf tip. This appealed to them.

They argue that now, 127 years on from that first nineteenth century report, we are close to a satisfying explanation of the 'inner workings' of the Saxifraga leaf. This is the result of a new cryofracture technique (cracking open the leaf while deeply frozen) to prepare plant material for viewing in a scanning-electron-microscope.

Hydathodes expel liquids onto the surface of the leaf. Sometimes called guttation, this seems to be a way for the leaf to regulate water pressure or mineral content, perhaps expel nasty chemicals and/or fight off things that might eat or kill the leaf. The crust on the leaf of a Saxifraga is what's left when the water evaporates, mostly calcium carbonate (limestone).

While we now have a better understanding of how the hydathode works the researchers still can't determine if the crusty deposits help the plant by simply allowing the exclusion of excess salt, or by providing some particular role when deposited on the leaf surface.


So I'm none the wiser as to how the air-conditioning system works. Perhaps reflecting solar radiation, perhaps by channeling air along the leaf surface (the crust are often on the margins) or perhaps by releasing a cooling layer of water (albeit salty and leaving a crust). Maybe the next papers from the laboratory and gardens of Cambridge University will help.

Tuesday, 12 September 2017

Islamic legacy an ornamental citrus to fight obesity



If you get the chance to journey around the Andalusian region of southern Spain, you'll see a lot of Seville or Bitter Orange (Citrus x aurantium, the 'bitter orange' group). That's because it grows well in this hot Mediterranean climate, it's shady all year and has evocative perfumes in flower and fruit.


The fruit is, as the common name says, bitter, and its oils end up in Chinotto, Grand Marnier and the candles of essential oil devotees.

In Seville, I was told, the Bitter Orange is grown because no-one will eat or use the fruit. The Brits (and I think the French), though, make marmalade out of it (with lots of pectin and sharp flavour it makes a perfect marmalade fruit).

In 1997 Professor David Mabberley sorted out the nomenclature of edible citrus, concluding that the botanical name for the bitter orange was probably based on a plant cultivated in Europe, now resting in the herbarium of Swedish nomenclatural overlord, Carl Linnaeus.

The 'x' in the name means hybrid. This is a hybrid between a pomelo (a large grapefruit like fruit) and a mandarin. You can read more about the pomelo and other hydrids in a few of my previous posts (1, 2, 3).

Within this hybrid group are both bitter and sweet oranges. Those at the bitter end have more of the pomelo (C. maxima), and those at the sweet end, more mandarin (C. reticulata) and sometimes called Citrus x sinensis.


I gather the ones with more pomelo have the distinctive winged stalk, often used to distinguish the bitter from the sweet in southern Spain. And the Bitter Orange is the landscape tree of choice.


The first orange trees arrived in Europe via the Middle East or India, originally from China or thereabouts, and the fruits would have had a thick bitter skin. The arrival of the orange tree as an ornamental plant in southern Spain seems to have come with the Moors who moved into Spain around 600 AD (although the orange trees seem to have come later). Today they feature strongly in the gardens of the alcázars and mosques throughout Andalusia.


When oranges first arrived in Europe a big belly was linked to happiness and good health (perhaps). Now of course we are (rightfully) obsessed with obesity, and about 'cures' for our tendency to over eat. The Bitter Orange has been mooted as a treatment of sorts. The fruits contain chemicals called synephrine alkaloids, like those found in an odd cone-producing plant called Ephedra. Dietary supplements from Ephedra have been banned in some countries due to adverse side effects.

Although the use of citrus oil is promising, in 2006 more clinical trials were deemed necessary 'to draw adequate conclusions regarding the safety and efficacy of Citrus aurantium ... for promoting weight loss'. However a more recent study (2016) concludes that 'bitter orange extract ... [is] ... safe for use in dietary supplements and foods at the commonly used doses'.

Personally I'd suggest you eat a little less, but enjoy the occasional toast and marmalade after exercising among Bitter Orange.   

Thanks to Jana Bate for her picture (at the top) of the orange groves within the Catedral de Santa María de la Sede in Seville, taken from the Giralda; and to Kit Wignall for being the subject of the fruit-eating experiment, photographed by Lynda Entwisle.

Tuesday, 5 September 2017

A toast to the Portuguese garden of John Allen


For most Australians, the gardens of Portugal are largely unknown, and unvisited: with the exception perhaps of a few around Sintra, near Lisbon, which I mentioned in passing in my Iberian posts. Many, like the country itself, seem to be looking back with a kind of melancholy to a time of prosperity and prestige.

The Quinta de Villar d'Allen, just outside the beautiful harbour city of Porto, is a garden not so much in decline but one certainly in a kind of eerie stasis. Back in June, I maneuvered our hire car to the centre of the Porto - a task requiring some art and luck - eager to check into our Pousada (the equivalent of the Spanish Parador hotel chain). As it turns out, the Pousada we booked was a few kilometres upstream along the River Douro so I had to coax our car through even narrower pedestrian streets, and back out of town.

The alternative Pousada was lovely in its own way but away from the main drag. While this meant more planning for visits into town, it did offer the opportunity to discover the local area and to seek out attractions not in the guide books. What I discovered a few hundred metres from the front gate was Villar d'Allen. Actually I had heard about this quinta, or country estate, in a talk by Richard Atkins a few months early, at a Friends of the Ballarat Botanical Gardens meeting. I have not expected to be anywhere near it, but here I was.


The garden is open to the public, by appointment. So on a morning walk into town I rang the number and organised to return that same day at 3.30 pm. We were met at the entrance by Isa Allen, and joined later by her husband Jose Alberto Allen. They are the fifth generation of Allens living in Portugal, with the first - George Allen - an early 18th century immigrant from England.

It was Alfonso Allen who bought this property, in 1839, beginning work on the garden almost immediately (keeping little, I think, of the original 18th century landscape). A key figure in the design of the garden was John Allen. I'm not sure what formal training he had but he was well connected, with his friends including the Scottish garden designer John Loudon and the creator of Pena Palace in Sintra, Ferdinand II (Alfonso, I think, also had connections to the great gardens of Portugal, sending camellias to Buçaco Palace in central Portugal).


These days the garden is a little rough around the edges, what we might describe as over-mature: with old trees and new plantings competing for space and our attention. 


Shaded under a heavy canopy are camellias, and lots of them. Most of the 400 or so specimens (perhaps up to 500) are labelled and quite a few have a connection to the Allen family. Portugal, like Australia, is unexpectedly a hot bed of camellia propagation and selection. Or at least both were. 

There is also an impressive stand of Chilean Wine Palms (Jubaea chilensis; although two of the four or five have died recently from fungal attack), a large Bunya Pine (Araucaria bidwillii), a very tall Blackwood (Acacia melanoxylon), as well as cedars and a podocarp or two. 


Mrs Allen was also keen to point out a very large Photinia and a yellow-flowered Philadelphis with a particularly sweet perfume. Although still a big garden with plenty of gardening to manage, the quinta is much reduced from the days of Alphonso and John. A large chunk of the property was excised when a new road was punched through the middle.

Like the garden, the inside of the house is preserved much as it would have been in the 19th century, with original furniture and wall coverings. I was impressed by a very large folio edition of Don Quixote (in Portuguese) and a pen (feather) used to sign the (first) constitution of Portugal in 1922. A post on the Camellias in Galica website provides some more history of the property and house.  


And when in Porto, one must drink Port. Jose Allen had joined the family wine business when young, learning to blend Port before joining the army and fighting in Africa for about four years. Now he makes small batches of port (a few thousand bottles each year), bottled under the family name.