Tuesday, 13 February 2018

Chestnut a surprising product of aquatic sedge


While on the subject of pseudo-cereals (but not superfoods), as I was last week, what about Water Chestnut? You will have guessed already that it's not a true chestnut (a species of Castanea), or even a horse chestnut (Aesculus hippocastanum), but something that might just grow in water.

In fact there are two edible plant products sold under this name. 'Chinese' Water Chestnut (above) is the corm ('bulb') of a sedge called Eleocharis dulcis, while what is sometimes also known as Water Caltrop (below) is the seed of a Lythrium (Loosestrife) relative called Trapa natans. Both grow in wet places.



The Water Caltrop is considered by Bohuslav Brouk, in his Plants Consumed by Man, to be a pseudo-cereal. According to Brouk, although the seed has been used since Neolithic times, today the fruits holding the seeds have more currency, as 'curios and souvenirs'. (I should add that this 1975 book was savaged at the time in many reviews, including this summary in the journal Economic Botany: '...[a] non-book, such a pretty package of misinformation, such inadequate coverage under such a grand title and pretentious jacket "blurb"...)

In Australia I've only seen the Chinese Water Chestnut for sale. In China the corm of Eleocharis dulcis is used in many dishes, often raw, although it has the attraction of remaining crunchy even when cooked. Yet despite its common name, Eleocharis dulcis grows naturally in many countries, including Australia. It has a tropical to subtropical distribution through much of Asia, across to Madagascar.


As Kathy Stewart and Bob Percival record in Bush Foods of New South Wales, the Chinese Water Chestnut is used by Aboriginal people in Australia, with old corms roasted and younger ones eaten raw. The stems are also used, to help in heal and seal open wounds. Magpie geese, also part of the diet of Northern Australian Aboriginal communities, graze heavily on this plant.

For more information on the Chinese Water Chestnut I eschewed Bohuslav Brouk in favour of Circular No. 956 put out by the USA Department of Agriculture in 1955... There I learn that the sedge is grown like 'paddy rice' in the south and east of China, where it is (or was) mostly called Matai, meaning 'horse's hoof'. The common name in English, Water Chestnut, is presumably a reference to the similarity of the corms to tree chestnuts.

To the USA palette, in the 1950s, the prepared Chinese Water Chestnut had a 'crisp, white, applelike flesh ... both sweet and starchy'. Uncooked it tasted to some like fresh coconut. Cooked it became a textural addition to omelets, macaroni and cheese, stews and the like. Small corms could be pickled, or fed to chooks.

And then there are the medicinal claims. For these I had to search beyond the USA Agricultural circular. There are claims that Chinese Water Chestnut has health benefits such as 'antimicrobial effects on bacteria, antioxidant activity, inhibition of inflammation and treatment for pharyngitis and laryngitis'. Indeed a recent study found that extracts from the peels of Chinese Water Chestnut, usually discarded during preparation, could be 'potentially used as a ... food supplement [for the] ... control or elimination of food borne pathogenic bacteria'.


Not bad for a plant of rather simple structure, essentially a collection of long green tubes. There are some 200 species of Eleocharis, with quite a few yet to be documented from South America (where most known species occur naturally). I can't think of any other Eleocharis species cultivated or appreciated in a similar way to Elecharis dulcis, although other sedges are of course used for thatching, basket-making and paper (e.g. Cyperus papyrus).

Images: habit shot of Eleocharis dulcis by Christian Fischer (CC BY-SA 3.0) and hosted by Wikipedia; images of corm by me; image of Water Caltrop fruit from Speciality Produce website.

Tuesday, 6 February 2018

Chias! It's a salvia


Who would have thought? Chia comes from Salvia columbariae, Salvia hispanica or Salvia polystachya, better known as sages and belonging to the mint family (Lamiaceae). Although unlike our amenity or culinary sages, these species are annuals.

Let's call them Chia Sage, as many do. Native to western North America, Chia Sage has been long harvested as a source of 'pseudo-cereal'. While Mediterraneans plucked the aromatic leaves from their sage, the Aztecs and Mayans gathered its seed.

Hernán Cortés - 'the killer' as portrayed by Neil Young - sent chia back to Spain but its use in the Americas was severely curtailed after the arrival of the Spanish. According to one source, Agua de chia (chia water) was, until the recent revival, the only remaining use of chia in the local diet.

Now of course the whole world is mad for chia. At least for now. It joins quinoa, kale and blueberries as so-called superfads - sorry, superfoods. To support its status I can report it is packed full of omega fatty acids, soluble dietary fibre and various proteins and minerals. All of which are probably good for you but as yet with no conclusive scientific support.

For me the most exciting thing about chia is the gel formed when you soak the seeds in water. Soluble fibres in the seed coat combine with the water to produce a goo of sago-like texture. That goo (along with the rest of suspended seed) contains plenty of fat and dietary fibre.

So yet another fascinating side story about Salvia to join the Brown Salvia, the Andean Silver-leaf Sage and Meadow Clary in the Talking Plants pantheon, only one of which is illustrated among the salvias below.




And while I'm here, I've been advised on the best authority (a friend of a friend) that the next superfood from the mint family will be the Shiso or Beefsteak Plant, Perilla frustecens. I remember seeing, and photographing, this plant a few years ago in the Milson Community Garden, Kirribilli, where I interviewed Yumi Sakauchi for Talking Plants on RN.


Just in case you are wondering, Quinoa is a chenopod (in the salt-bush family) from South America, an entirely different and unrelated pseudo-cereal, and, sigh, superfood.

PS: Paul Ward, via Facebook (6 February 2018) adds: Basil seeds are popularly used in SE Asia for drinks in a similar way that chia is used. Soaked basil seeds form a mucilage around their seeds. The mucilage formed on the seeds of clary sage ( S. sclaria) has been used in Europe for removing foreign objects from the eyes. A seed is put into ones eye, and the mucilage attaches to the grit or whatever is caught in the eye. And is then easily removed.

Images: At the top is a picture of Salvia columbariae taken by Gary A. Monroe, hosted by the USDA-NRCS PLANTS Database. The other images are from my own photograph collection: the Shiso from Milson Community Garden; a close up of Salvia canariensis from Gran Canaria (Spain); Salvia pratensis in the seed orchard at Wakehurst Place (Royal Botanic Gardens Kew, UK); and the salvia border at Kew Gardens (Royal Botanic Gardens Kew, UK).

Tuesday, 30 January 2018

Floral clocks and flowering thyme


While preparing for last weekend's chat about 'time' on ABC RN's Blueprint for Living, I got diverted on Carl Linnaeus's horologium florae, his floral clock. An eccentric and impossible folly, but what fun!

Here in Melbourne we are proud of our floral clock, a nineteenth-century sensation reaching Australia in the 1960s. It consists of a buried clock, Swiss made, with giant hands sweeping across a carefully manicured garden bed. At times long-lived box hedges have added structure, but mostly annuals such as begonias and marigolds contribute bling to the timepiece. Beautiful – at least to some eyes – and reasonably functional.


The original concept of a Floral Clock was quite different, and even barmier. By the mid eighteenth century we were starting to get a grip on the variety and apparent vagaries of plant reproduction. Different plants not only flower at different times of the year, but at different times of the day. Some species are quite specific as to when they open and shut their flowers, to take advantage for example of obligate morning or evening pollinators. This led Swedish biologist Carl Linnaeus*, creator of what we call our binomial system of naming (e.g. Homo sapiens, for us, humans), to postulate a horologium florae.

With judicious planting, one can imagine a garden where the open flowers tell you the time day. In the Swedish city of Uppsala, where this idea first took root**, you might bounce out of bed when the Dandelion (Taraxacum officinale) flower-head unfurls at 6 am, rush to work when it shuts between 8 and 10 am, grab a sandwich at noon when the Field Marigold (Calendula arvensis) flower-heads close, leave work at 6 pm when the Sad Geranium (Pelargonium triste) finally opens its dull yellow flowers and, if you like, party until the Queen of the Night cactus (Selenicereus grandiflorus) blooms at midnight.

Let’s get something clear up front though. This is like picking your dream sports team of all time or forming the world’s best super band. It’s a paper or mental exercise. A true Floral Clock can’t be created in the real world. These plants won’t grow together in the same place, they won’t all flower on the same day of the year (each flower of the Queen of the Night cactus, for example, opens for one night only), you would have to re-calibrate for every degree of latitude or altitude, and depending on the weather some might not open at all.

While a full functioning Floral Clock is a folly, you could conceivably create a coarse local variant that might work in spring or thereabouts. You could start with two Victorian species of flax lily (Dianella), one of which (Dianella amoena) opens early to mid-morning, the other (Dianella tarda) early to mid-afternoon. But then you know when it’s mid-morning or mid-afternoon don’t you? Perhaps it is better to spend your time wondering how it is that plants spend their own.


Now, plants set their own clocks from the amount and quality of the daylight they receive. They have a system for tracking seasonal changes in day length, triggering when they flower or renew growth. The variations within a single day are controlled by light, temperature and even humidity, plus an inbuilt circadian rhythm like animals. Such precision is the result of evolution, with successful plants protecting their assets (flowers) until a suitable pollinator is active. For the night-flowering cactus it’s a moth. For the two flax lilies, it may be the same or different species of native bees.

Some plants will open and close their flowers on a daily cycle, by growing new cells every day in the inside (to open) or outside (to close), or by expanding and contracting existing cells in the petals. It’s worth the effort to protect delicate parts from wind, rain and dew, and to keep pollen dry and ready for action. Plants growing in tough environments are more likely to have these diurnal cycles. A good example is Pigface (Carpobrotus glaucescens), a succulent adapted to dry sand dunes, which has daisy-like flowers that close up every night. The Sensitive Plant (Mimosa pudica) folds up its leaves each night to protect that equally important, and in this case sensitive, part of the plant.

The flowering head of a Sunflower (Helianthus annuus) takes it all a step further, arcing during the day in response to its own internal clock. Young sunflower plants (with their flower-heads unopened) track the sun from it rising in the east to its setting in the west, then get themselves sorted overnight so they can do the same the next day. Once the giant yellow flower-head opens, it stops moving about and faces east.

The sunflower has a circadian mechanism behind its solar tracking, and then some internal signalling to position its mature flower-heads eastward. The solar tracking is caused by different growth rates on the sunny and shady side of the stem. During the day the cells on the east side grow a little faster than those on the west, and then vice versa at night. This all stops when the elongation of the stem stops and the best orientation for an open flower is facing the morning sun - warm flowers attract more bees.


Plants do keep time in other ways. Flowers can last a few hours (our night-flowering cactus) or a few months (moth orchids), and the entire life cycle can be a matter of a few months (desert annuals) to thousands of years (the Bristlecone Pine, Pinus longaeva). Annuals typically flower once and die, all within 12 months, but other plants, such as the Century Plant (Agave americana) and several palms, will live for a few decades then flower once and die. For most woody plants and trees, though, they flower each year and continue growing until like us they senesce.

There are plenty of seasonal cycles of course, allowing plants to survive and thrive in their particular nook and cranny of the world. We can manipulate these cycles, as we do with the Christmas Poinsettia. In mid-winter in Australia, a garden Poinsettia produces red or pink leaf-like bracts around its tiny flowers. The amount of colour change in these bracts depends on their exposure to sunlight, or rather lack of exposure. They need long 'dark periods' for about three months before they flower. Northern Hemisphere gardeners report that interrupting the ‘long night’ by even flashing with a torch during October through to December may stop the leaves changing colour.

To get our Poinsettias flowering, and ‘bracting’, in nurseries around Christmas we manipulate their environment. Glasshouses are set up to provide artificially long nights and the Poinsettia thinks its winter. Although a plant growing in my office building (hello Frank Udovicic!) persists in flowering close to Christmas without any overt manipulation, perhaps due to day length variations on its windowsill. Plant life is seldom simple and it seems you can’t really set your watch, or your Christmas shopping schedule, from a flower.



*Carl’s father devised their surname, Linnaeus, so he could register at university (before then he, like many others of the time, had no need of a surname). The Swedish word ‘linn’ is used for what we call the Linden or Lime Tree (Tilia) and the freshly minted name honoured an impressive specimen of Linden growing beside their family home. So it is no wonder Carl had such a passion for plants. Perhaps too much. His classification system for plants was based largely on their sexual organs, the flowers, and considered by some to be a little too explicit – loathsome harlotry according to one contemporary commentator.

**My source for the plants Linnaeus proposed for his horologium florae was a copy of The Natural History of Plants by Anton Kerner von Marilaun, published in 1896, and part of the State Botanical Collection library at Royal Botanic Gardens Victoria.


Images: Flowering Thyme, of course. In the Royal Botanic Gardens Victoria, Melbourne Gardens, a few months ago. And just above. a much reproduced image of Carl Linnaeus, this one from a sign in the Jardin Botanico Atlantico, Gijon, Spain

Tuesday, 23 January 2018

Isolated euphorb survives and thrives despite tragic plane crash



Eighty years ago, an Australian National Airways passenger plane, a DC-2, crashed here, on the slopes of Mount Dandenong, in the outskirts of Melbourne. All 18 people on board died when the pilot of the flight overshot Essendon Airport by 32 kilometres on a cloudy afternoon in late October, 1938, a year before the start of World War Two.

The inquiry following the crash led to various air safety improvements including an air traffic control system in Australia that became the model for airports around the world. A memorial was erected at the crash site in 1978.

Near to the memorial is an isolated population of an odd little plant called Beyeria lanceolata. Beyeria is an Australian endemic - all 24 species occur naturally only in Australia - and sometimes (like a few unrelated genera) called Turpentine Bush.


The genus belongs to the plant family Euphorbiaceae, notorious for its single-sex flowers with rather odd and diverse floral apparati, as well as in Africa mostly for the cactus-like Euphorbia species. In recent years a few smaller families have been hived off but Euphorbiaceae remains large (c. 230 genera and 5700 species) and florally odd.

Like other species of Beyeria, the male flowers have obscure petals and consist mostly of a cluster of anthers, in this case poking out of kicked back sepals (the layer outside the petals). The female flowers are a single ovary clasped by green sepals. The leaves are long and narrow.


Beyeria lanceolata grows mostly in East Gippsland, where is is rare but scattered widely, and drifts ever so briefly across the border into southern NSW (where, perversely, the 'type' specimen of the species was collected). West of the township of Sale, though, its only extant population is near this crash site (excluding a likely misidentification from Point Nepean).

The plant was collected from Mount Dandenong in 1949, 11 years after the crash and a few years after the end of the Second World War. At the time of that gathering, Government Botanist Jim Willis noted that this species was 're-located in the Dandenongs' and there were 'many shrubs covering about quarter of an acre'.

Late last year botanist Neville Walsh re-re-located the species in Mount Dandenong - although to be fair it had not really gone missing between 1949 and 2017- estimating its extent at 'about a house block'. Even allowing for house blocks having become generally smaller over the intervening 68 years you'd have to say, as Neville did, that this population has remained remarkably stable.


Still, Neville was there to collect seed, from fruits like this, just in case.

There are other plants with the bulk of their distribution in East Gippsland, and sometimes further northward, but with an isolated occurrence somewhere in the west or centre of Victoria. Examples in the fern and fern ally world include Psilotum nudum, the Fork Fern, in the Grampians; Lindsaea mirophylla the Lacy Wedge-fern in the Dandenongs and nearby; and Tmesipteris ovatum, the Oval Fork-fern from Wilson's Promontory up to the Dandenongs. 

In some cases the clearing of habitat will have caused the disjunction although you'd expect a few older records in between. None of these examples have any historical records connecting the present outliers to their eastern stronghold.

In the case of our Beyeria you might be thinking I introduced the plane crash as a possible vector. Perhaps a seed had become attached to the fuselage? Well I did, but it seems not. The plane was travelling from Adelaide rather than from the east, and there is a pesky August 1914 record - at the start of the World War One - from the same locality.

Images: all from VicFlora, taken by Jeff Jeanes, Neville Walsh and Andre Messina (credits on source page).

Tuesday, 16 January 2018

Streaky Box Elder a mixed up and unwanted plant


This is one confusing plant. Not just the striking - or shocking if you view variegation the way I do - albino streaks through every part of the normally green bits of the tree. But its identity and its name.

These fruits are the typical winged fruit of a maple, or Acer. But we all know maples have those lovely hand-like (palmate) leaves. Well, most of them (particularly in North America) do but this one doesn't.

The leaves are divided into 'leaflets', very like an ash tree or perhaps an elder. Sure enough, the common names include Box Elder, which references its odd leaves (and, I gather, to the wood being reminiscent of a Boxwood, Buxus), and Ash-leaved Maple, which references ... well, the ash, Fraxinus.


Acer negundo, as we botanists call it, is tough old species. We have this giant old one near the Terrace Tea Rooms in Melbourne Gardens, most of it living up the cultivar name of 'Variegatum', and the modified common name, Variegated Box Elder.

The species name, negundo, is another nod to look-alike plant, Vitex negundo. That plant also has leaves divided into leaflets, five in its case, and was named after a local Sanskrit/Bengali word for the plant, nirgudi.

The Box Elders have three to seven, or rarely nine, leaflets. A handful of varieties have been described based on the number of leaflets, how hairy they are, and the colour of the stems (some are a beautiful glaucous grey). Ours seems to match the variant found throughout most of the USA called variety negundo.

So much for its name. Those white streaks and blotches bother me in the leaves but on the early summer day when I took these pictures, I have to say I was quite taken by the veils of white fruits. That's cool. And no doubt responsible for another of this cultivar's common names, Ghost Maple.


No sooner do I find myself attracted to a variegated plant though and it shows me its flaws. This one is reverting to green foliage and fruits in various places. Which begs the obvious question: will the entire plant eventually become green-washed? 

Variegation you'll recall is mostly likely the result of a genetic mutation. It seems that in this specimen the 'defect' holds true mostly but ever now and then reverts back to normal at a growing tip - so one branch becomes green again. What you can't tell from a single observation like this is whether the tree is transitioning - if I can use that term - to no variegation, or simply expressing a similar proportion of reversion to what it's done all its life.

They say this cultivar is one of the most commonly grown in Australia and you do see planted as a street tree not far from the Melbourne Gardens. So I could soon make my own assessment as to whether there more all-green leaves on older trees or whether they are in roughly the same proportion no matter what the age of the tree.That all assumes of course there is no manipulation of the system, which it turns out there is.


In VicFlora, where the species is listed as a 'naturalised' species for the State (i.e. a weed that has become established among natural vegetation) we read that 'variegated forms soon revert to wholly green-leaved plants in the wild'. But, 'in cultivation, green-leaved sucker stems are usually removed to retain the variegated foliage of the central stem'. These statements are borrowed from the Horticultural Flora of South-eastern Australia.

The sucker stems in Melbourne Gardens are all over the tree, as they are in the street trees nearby, and it seems their days are numbered. Otherwise our Variegated Box Elder would simply be a Box Elder.

Given the rather disparaging remarks made about the potential of this species as a weed of forests and woodlands, particularly near rivers, perhaps instead of removing green shoots we should remove the whole tree. In Victoria Box Elder is already 'a problem at Wilsons Reserve in Ivanhoe and in Knox City Council'. 'In fact' says the Queensland-based Weeds of Australia site, 'some environmentalists believe it to be among the worst environmental weeds growing along waterways in Melbourne'.

This is where our carefully manicured Variegated Box Elder saves the day. According to the Horticultural Flora it produces sterile seed. Lots of it, but none perpetuating the parent. I'm assuming this refers to the variegated-leaf branches only, providing another incentive to trim the green growth. The choice seems to be between a weedy green tree and a barren but benign ghost-like mutant.

Tuesday, 9 January 2018

Giant asparagus makes up for lack of mezcal


In late October, a couple of huge asparagus-like stalks erupted from Agave parryi rosettes in Melbourne Gardens. A month later (below) the stalks transformed into what look like small pine trees, flaunting brushes of golden flowers. The species is scattered through the Californian Garden (above) and atop Guilfoyle's Volcano (below, along with Echium and barrel cacti vying for attention).


The Mescal Agave, as commonly called, is one of 160 species of Agave, all of which come from North and South America, mostly from Central America and particularly from Mexico. Conveniently, given the structure of the young flowering stalk, Agave is these days considered to be a member of the Asparagaceae, a rather large family now of more than 100 genera and nearly 3000 species.

So what's with the common name Mescal. Firstly the spelling. That's the way many non-Mexicans spell the name of the distilled agave spirit, considered to be a 'kind of' Tequila. 

In fact, the legal and Mexican spelling of mezcal/mescal, the spirit distilled from Agave, is mezcal. Mezcal, according to Amy Stewart, author of the entertaining and informative The Drunken Botanist, can today only be made in five Mexican states, from species of Agave species growing in those areas. 

Tequila needs to come from somewhere near the city of Tequila* and from Agave tequilana 'Weber Blue' (although most tequila drunk outside Mexico, again according to Amy Stewart, is fermented from sugars from various agave as well as other sources). There are other agave-based spirits with their own fancy names.

What I can't find is Agave parryi listed specifically as the source of any agave-based spirit: mezcal, tequila or otherwise. Native Americans used the species for 'food, fibre, soap and medicine' and although linked to pulque (an inferior kind of alchoholic beverage) and mezcal on some sites the reference seems to be more a general one and could relate to a range of agave species.


Mescal Agave comes from high altitude grasslands, scrub and woodlands in Arizona, New Mexico and northern Mexico, and according to the Missouri Botanical Gardens site it flowers 'infrequently', 'rarely' and more helpfully, after 10-15 years (although sometimes taking 20-30 years, which is far closer to rarely).

Mostly it is grown for its attractive leaves, glaucous grey with a sharp terminal point and neat imprints of the leaf from either side, a ghost memory from the time they shared a common bud.


Like most agaves, each rosette will flower once, then die. Pups or offsets at the base will then take over until they too flower and die. And so on. Here you can see a well known species, Agave americana (the Century Plant), going through its paces on a roadside in South Yarra.


We have plenty of Mescal Agave pups - and even more semi-mature canines - so expect to enjoy a procession of summer blooms over coming years. I know our rainbow lorikeets will.


Images: the asparagus-like shoot next to Neville Walsh was taken on 23 October 2017, the rest are from 28 November 2017. The species is sometimes split into varieties. Ours would be variety truncata.

*As Wayne Robinson, President of The Cactus and Succulent Society of Australia, advises in a comment below, 'somewhere near the town of Tequila' somewhat underplays the extent of the region... For the full extent of the Tequila appellation region, see Tequila.net. Thanks Wayne!

Tuesday, 2 January 2018

Stealing the soul of the coral flower


We've acquired a rather planned and, so far, very neat back garden. This is somewhat of a novelty for us but an enjoyable one. Part of that orderliness are strategically placed heucheras from North America. There is a bronze-leaved one and a silver-green leaved one. The former has whitish flowers, the latter deep-pinkish. All very nice and neat.

(My wife) Lynda is keen to do a painting of its flowers, and maybe it more generally, so I was asked to take some photographs with my android-less camera. The enlarged images make it easier to see, and draw, the attachment of various floral parts and detail of important things like surface hairs.

Lynda was also trying to work out what was a petal and what was a sepal, to gain a deep understanding of the flower before she steals (or is it elevates?) its soul. First I needed to do much the same by giving it a name. The bronze-leaved forms were purchased as 'Marmalade', 'Peach Flambe', or perhaps a mix of both, but we had no name for the silver-green-leaved, deep-pink-flowered form.


I'm thinking it is one of the so-called Bressingham Hybrids, Heuchera x brizoides, crosses between Heuchera sanguinea and Heuchera micrantha. There is certainly some Heuchera sanguinea in there, such as having the male parts (the stamens) shorter than the petals, and presumably some Heuchera micrantha in the very long sprays of flowers.  


The flower is tricky to decipher but I think the two pictures above show the structure pretty well. The floral bits are mostly in groups of five. The sepals (the outer layer, sometimes called the calyx) and petals alternate along the top of a puffy pink cup, all covered in hairs tipped with glistening, deep red, spheres. The petals in the pictures above are thinner and attached behind the neat V of where the sepals join. In this next picture you can see the slightly weaker petals between the three sepals on the bottom half of the light pink flower.


In older flowers, like the couple behind the light pink one, the sepals redden up and the softer petals shrivel. You can see that clearly in this next picture, with not trace of the petals.


The common name for Heuchera is Coral Bell, or Alum Root. Coral Bell refers to the pink flowers of some species, particularly Heuchera sanguinea, and works well for what we have in our garden. Alum Root is apparently something to do with the roots being used in pickling, like alum (aluminium sulfate). The astringent properties of the roots also make it useful in folk remedies to 'shrink tissues' - blood noses, sore throats and piles are mentioned in dispatches.


All 55 or so species of Heuchera come from North America, where they grow mostly in woodlands, favouring crevices and hillsides. Like other members of the family Saxifragaceae you find them more often in cooler regions: I posted a story a few months ago about an alpine member of this family's namesake, Saxifraga.

It's now up to Lynda to represent the beauty and the structure of this tiny flower in a water colour painting, no matter what name I give the cultivar and no matter what each of those floral bits does. All that is the devil's work!

Tuesday, 26 December 2017

Floral rain and flames brighten Chinese urban forest


I'll finish the year with another story from Chongqing, in central China. While visiting in October I noticed smudges of orange and red in the plentiful urban forests around the city. Firstly from my hotel room, then from the pagoda viewing platform at Eling Park, and to be fair, pretty much from every vantage point in the city...


They are part of the remnant or regenerated forest that carpets the hillsides in Chongqing, but also planted in formal garden beds and as a street tree.


You might call them golden rain, flames or bougainvillea-like-sprays. These words combine to provide some of the names for the local Koelreuteria bipinnata with its orange-shaded, puffy, three-winged, papery fruit.


The Bougainvillea Golden Rain Tree as one common name has it, has small, yellow flowers, with a fleck or red at the base of the petals. But the flowers are produced in large clusters, presumably the golden rain. Or maybe that's the flush of yellow leaves in autumn? The Chinese Flame Tree common name hints strongly to its origins, and to the colour of the fruits. 

There are three species, two in China and Japan and one split between Taiwan and (apparently) Fiji. All seem to be tolerant of tough urban conditions, tolerating pollution and 'challenging' soils.

Koelreuteria paniculata typically has once divided leaves (or barely twice 'pinnate') and grows naturally in China, Korea and Japan. In China it occurs in Anhui, Gansu, Hebei, Henan, Liaoning, Shaanxi, Shandong, Sichuan and Yunnan, but is widely planted elsewhere, including Australia. 

Koelreuteria elegans subspecies formosana only grows naturally in Taiwan and has 'leaflets' (the ultimate leafy bits in the divided leaf) with a strongly oblique base. It is planted and weedy in northern Australia.


I'm thinking the species I saw and photographed in Chongqing is the third species, Koelreuteria bipinnata, with twice pinnate leaves (see above). It comes from natural forested slopes in Guangdong, Guangxi, Guizhou, Hubei, Hunan, Sichuan and Yunnan, as well as Japan. Until the 1990s, Chongqing was part of Sichuan so I'm presuming the species is more or less native to the area.

According to John Grimshaw and Ross Bayton's New Trees: Recent Introductions to Cultivation, Koelreuteria bipinnata was introduced into France in 1887 and California in 1911. It didn't become popular in Europe but is now widespread in warmer parts of North America. Although not considered 'hardy' in Lonon and Paris, Grimshaw and Bayton suggest that with the changing climate it is worth planting now in southern England. In Australia this species is rarely planted but there are three specimens in Melbourne Gardens, two near the Plant Craft Cottage.

In terms of which species to try, there is not much in it. All three are relatively minor variations on a theme, even with the additional flourishes such as pink new growth and pinker fruits available in cultivars of paniculata. And they should all do well in the warming, drying climate predicted for southern Australia. Possibly too well of course and I'd prefer to not see golden rain and fruity flames from every vantage point in Melbourne.

Tuesday, 19 December 2017

Another parasite for Christmas, Cistanche


This being my last post before Christmas Day it's time to talk about parasites. Not those that visit you around this time of year in search of gifts and hospitality, but plants that survive off the 'generosity' of others. I've blogged about a few of them already.

The kiss-inducing mistletoe (Viscum album) is a parasite, or partly so. We call it a hemiparasite in recognition of it producing its own sugars through photosynthesis, but drawing most of its water and nutrients from the host plant.


The Western Australian Christmas Tree, Nuytsia floribunda, does the same. These hemiparasites can be attached to roots or stems. Other mistletoes are fully parasitic, such as the leafless Tristerix aphyllus growing on cactus stems.

The tiny Christmas Lantern, Thismia, is parasitic on fungi and grows entirely under the leaf litter - flower and all. Due to its obscure habit, it is unlikely to adorn a festive table, although its flower is a Christmassy red colour.

This next one isn't so beautiful in form or colour. It's the Lesser Broomrape, Orobanche minor, photographed here in the Melbourne Gardens, in early November.


The Orobanchaceae is a relatively large family (around 2000 species) of root parasites, many - such as this one - having no chlorophyll (so no photosynthesis and entirely dependent on their hosts). The Ivy Broomrape, Orobanche hederae, was one I saw commonly in the UK, and this Lesser Broomrape pops up here and there around Melbourne and much of southern Australia.

There are 140 species of Orobanche with only a variety, of Orobanche cernua, native to Australia. The Lesser Broomrape (above) was introduced into Australia from Europe, presumably inadvertently as cargo on one of its many hosts. In this case it seems to be attached to the roots of a Plectranthus.


But today I want to make special mention of a weird desert plant called Cistanche. This genus came to my attention most recently in a talk at the Chinese Association of Botanic Gardens meeting in Chongqing, China, in October. Unfortunately the presentation was in Mandarin but I could at least marvel at the photographs (the image above shows a warty underground stem, the picture at the top of the post, Cistanche deserticola in flower).

The genus extends from Europe into Asia (or vice versa...), with five species native to China. Medicines are extracted from a few of the Chinese species but Cistanche deserticola ('desert loving') is the mostly commonly used: the Flora of China states that "the stems are used medicinally for enriching the blood, invigorating the kidney and strengthening yang sexuality, and relaxing the bowels". It has become increasingly popular in recent years as an aphrodisiac, and more recently, shown to have potential as an anti-colon cancer therapy. 


I gathered from the visuals in the talk that Cistanche deserticola, or Desert Broomrape, is grown extensively in dry parts of China. It was planted in long rows, near to and perhaps parasitic on a plant that looked like Tamarisk (Tamarix) but was more likely to be Saxaul (Haloxylon ammodendron).

Huge quantities - there were lots of massive numbers and illustrations of harvest bounty - of the root are used for medicines. An annual conference is held each year in China to discuss the genus and its cultivation. 


A newspaper article from China in 2009 argued that cultivating and harvesting Desert Broomrape made the planting of Saxaul economic. Saxaul is a drought-resistant shrub used to stabilise sandy deserts in western China. However without the money brought in through the Broomrape, there is no financial incentive, or ability, to plant Saxaul.

Due to my linguistic limitations I don't know the full environmental and economic consequences of this kind of farming but Broomrape is clearly big business in China and the rows upon rows of pine-apple-like flowering stems are impressive. I just wished I'd taken more pictures during the talk.

Anyway, Merry Christmas or happy festive season, and may your bowels be relaxed and all other desires satisfied.

Images: the top image is from Urbol, the picture of the harvested root from Rainbow, and the Christmas mistletoe, from The Sun.