Tuesday, 3 May 2016

Subtle colours in the proud Sydney sun


It was late summer in the inner west of Sydney, a week or two after the Mardi Gras but nobody told the street trees. There were crepe myrtles in vivid pink and purple, Tibouchina in that irridescent blue you only see otherwise in parades and festivals, and every now and then, bursting out from a tiny front yard, a giant pom-pom of ice-creamy frangipani.

So what does this Melburnian do in such an visually charged streetscape? I notice an odd form of the Coast or Sea Hibiscus. The yellow-flowered Hibiscus tiliaceus (also classified as Talipariti tiliaceum by some) is exotic and adventurous in its own way, travelling as it does around the world taking root on tropical and subtropical shores. My memories of it are from Borneo, some island off Queensland and Sydney's Royal Botanic Garden, but it is native to much of northern Australia and much of the pantropical world.

You can eat it, preferably wrapped around something else a little tastier, or eat off it (as a plate). In Australia I gather roots and shoots are eaten by Indigenous peoples in the north, and there are a range of medicinal benefits associated with the ingestion of leaves, bark and flowers - but as if often the case, on of those 'benefits' is as a laxative.

Now the flower in that top picture is clearly orange, not yellow. That's presumably because the flowers of the species open yellow in the morning and redden up later in the day. I only remember them as yellow, but perhaps that's because I tend to botanise idly in the mornings. This picture was around brunch time but perhaps they were yesterday's flowers.

The hint of red in the leaves, however, suggests a well-known cultivar. Hibiscus tiliaceus 'Rubra', sometimes called the Red or Bronze Cottonwood, is I think what grabbed my attention that steamy warm day in Sydney. My pictures were stolen glimpses as we walked past (not the high photographic art you are used to...) but it's a smart looking tree with deep green leaves with hints of bronze, and pale apricot orange flowers.


This cultivar does grow in Melbourne and we have a coppice of youngish plants in the [Rhododendron] Vireya Bed at Melbourne Gardens, near the Ornamental Lake east of the Rose Pavilion. There were not in flower in March (or now) but they look pretty enough in leaf. Sometimes you have to travel far away to appreciate what is close at hand, or some such glib saw.

Speaking of wood cutting devices, in a recent paper demonstrating how a brittle volcanic glass (obsidian) was used to make axe blades many thousands of years ago in Papua New Guinea, local craftsman used both Hibiscus tiliaceus and Hibiscus tiliaceus 'Rubra' to make a light but hard axe handle for a reconstructed archaeological tools. I'm not sure what this says about the origin of the cultivar 'Rubra' but perhaps it occurs naturally in this region.

To most of us the flower of the hibiscus is the attractant. I've blogged plenty of times about Hibiscus species, or its relatives in the family Malvaceae, and I'm being a little disingenuous saying they aren't Madi Gras standard. There flowers are hard to miss, and frequently bold and brash. It was just in this setting they were bystanders to the parade of pinks, purples and blues.

And rest assured my head is turned by flower colours in that spectrum. This is the shrub I photographed, with a small Jacaranda to its left. If that Jacaranda had been in full purple haze (or purple rain, if that's your thing) I wouldn't have taken a second glance at the Hibiscus.


Feedback: Lynda Newnam responded (3 May 2016) to this post on Facebook, noting that Cotton Tree gives it name to a beautiful spot in Maroochydore, Queensland, posting the following 'postcard':

Tuesday, 26 April 2016

Water Lily wavy for a day



Plants use flowers to attract pollinators. Sometimes they co-opt a nearby leaf or two to add to the allure, but mostly its the flower that does all the attracting. (There are of course plants that simply shed their pollen to the wind or water; their flowers tend to be less attractive, to us as much as other animals.)

Our experience with cut flowers is that they last for a few days to a few weeks. Attached to the plant we might expect them to last longer and in many cases (think of a rose or a camellia bloom) a single flower can be enjoyed for weeks. Sometimes, like the Moth Orchid (Phalaenopsis) they hang around for months.

Oddly, given all the energy needed and outcome required, there are flowers that last a day or two only. The Day Lily (Hemerocallis species) does what it says on the tin: the flowers open in the morning and start withering away that evening. The Titan Arum (Amorphophallus titanum) lasts an extra day, but for a flower structure that can be over two metres long and wide, that's a big investment for a 48-hour sexual display.

The flowers of the Yesterday Today and Tomorrow (Brunfelsia) last a few days, changing colour daily, as do the much showier flowers of the giant Victoria Lily (Victoria). Plenty of variation but our expectation, or at least mine, is that most flowers will hang around for a week at least. So when I noticed over summer the Wavy Marshwort (Nymphoides crenata) flowers vanishing overnight to appear next morning as pink buds like those above I assumed the Marshwort was just closing up its flowers to protect their delicate petals (I riff on this in my post on Shy Flowers).


Wary of making assumptions I decided to run an experiment. Neville Walsh and I tagged a couple of flowers with a knotted piece of vegetation. I didn't photograph them on that day, but here is what the flower looked like the next morning (it's the one on the left, with the loose garland).


The tagged flowers were all spent but in each case a fresh bud was sitting erect, right next to it. By mid-morning the bud was open and the old one hardly noticeable except to the experimental scientist.


We checked the next day too, just to make sure our first flowers hadn't been opened for days or weeks, with us tracking their last hours just by chance. Sure enough, the new flower withered in the evening, never to open again.

To the casual observer the pond looks more or less the same every day, for weeks on end. That is what the Wavy Marshwort does, at least at Melbourne Gardens.


[The astute blog observer will notice this last picture is taken on the same day as the image at the top of the post - my pictures of the next day were very unattractive. But take my word for it, at this scale the daubs of yellow looked pretty much the same the next day, and the next, and the next...]

Tuesday, 19 April 2016

Giant daisy succumbs to Robinson Crusoe's goats


I saw a humming bird in Chile once. It hummed by as I peered into the flower of a Chilean Chilean Bellflower (Lapageria rosea). Both were in the garden of Hotel Antumalal in Pucón where I was staying on my way to see Monkey Puzzle Trees in the shadow of the smoking Villarica Volcano.

Still, enough bragging about humming birds (one), Chilean wild flowers (in a garden) and latent danger (it was weeks since the last eruption...). What I didn't see - in a garden or in the wild - was the Robinson Crusoe Island Cabbage Tree and its humming bird pollinator. Now that would have been a story to tell.

Dendroseris litoralis is not so rare in cultivation but you have to travel to Robinson Crusoe Island in the Juan Fernández Islands archipelago, about 600 kilometres off the coast of Chile, to see it in the wild. This big-leaved daisy has been described as 'amongst the rarest plant species in the world', threatened by habitat distruction and feral goat grazing.



With its large rubbery leaves, the Robinson Crusoe Island Cabbage Tree looks a bit like some of the giant thistles (Sonchus species) on the Canary Islands, having adapted to a similar island environment.  It's a woody, fast-growing plant. This specimen in our nursery grew from a seedling donated just a few years ago by local grower and collector Alistair Watt.


Robinson Crusoe Island is named after the famous Daniel Defoe character who was shipwrecked on an island for 28 years, at first alone and later with his friend Friday. This particular island in the Juan Fernández Islands was where a real life sailor, Alexander Selkirk, was marooned for five years in the early eighteenth century. According to Wikipedia, the Chilean government changed the islands name from Más a Tierra to Robinson Crusoe in 1966, to 'reflect the literary lore associated with the island and to lure tourists'.

Robinson Crusoe Island is home to other botanical oddities, such as the Chonta Palm (Juania australis), and seems to be worth adding to your bucket list if you like botanically bizarre island floras (along with Socotra, Canary, New Caledonia...)

Until recently the Cabbage Tree was reduced only a few individuals on the island but propagation in gardens and, I'm assuming some reintroduction in its native habitat, have tipped the balance a little. However it is still consider critically endangered in the wild.

Although it has been shown that hummingbirds are the most likely pollinator (attracted by its sugary nectar), it doesn't actually need them. Along with about half the world's plants, this particular species of Dendroseris is what we call 'self-compatible'. That is, it can set seed without pollen from another individual. This makes it a perfect plant for gardens but perhaps not adaptable enough in the wild (cross breeding allows the mixing of genes and generally better ability to adapt to change).

In Daniel Defoe's novel, Robinson Crusoe survives with the help of a few crops, his bible and some goats. On Crusoe's namesake island it is the goats that are the undoing of the Cabbage Tree. That and the 800 or so extra humans.


Images: the plant in the Melbourne Gardens nursery, 18 December 2015.

Tuesday, 12 April 2016

Good health from a happy tree in a wise location


It's a happy person that doesn't have cancer. And it's a Happy Tree that might provide one of the cures for cancers.

Camtothecin was discovered by western medicine in the 1950s, when it was extracted from what we call the Happy Tree, from the Chinese name Xi Shu. Botanically it's known as Camtotheca acuminata, one of two species in the genus Camtotheca - a name that translates as 'curved sheath', a possible reference to the miniature banana-like fruits.


The tree is native to southern China and Tibet, but nowadays at least uncommon in nature. Seed from one of the remaining 4000 trees was collected from Yunnan Province about 20 years ago by our Curator of Chinese Collections, Terry Smyth.

According to a 2011 report by the Rural Industries Research and Development Corporation (RIRDC), demand for this chemical worldwide is estimated to require at least 100 million trees. So we need to grow more than 99,996,000. We have nine growing in Melbourne Gardens, all sourced from the seed collected by Terry.

The tree is described in the report as 'easy to grow in Australia' but does need a good source of moisture. One of our Senior Curators, and water guru, Peter Symes thinks the tree I've photographed here has done so well because of its roots are sourcing moisture from the lake. Colleague Steven Liu, who grew up in China, says it seems to grow better here than in its home country.

As you can see in the top photograph, this particular tree (the tall one) was planted next to the William Tell Rest House. This structure is a miniature version of a similarly named chapel in Lucerne, Switzerland. I don't know of any particular resonance with the Melbourne Gardens but happily, according to the 15th century legend, William Tell's arrow splits the apple on top of a nobleman's son's head and so lived to have his tale told.


These are the first pictures of the first flowering of our Happy Tree. The flowers are in a head, like a pom pom, with the male parts (stamens) prominent. If you look closely you can some tiny lime-green blobs on the spongy surface of the female centre of each flower; this is where the pollen from another flower needs to land.The flower without stamens in the top picture is older and, if fertilised, on its way to producing a cluster of scimitar-shaped fruits. As Terry says, 'the globular flowers are interesting but not particularly beautiful' (they are certainly high in the tree and difficult to photograph).

But chemicals in its stem and bark are worth celebrating. While you here plenty of reports of cancer-curing plants, camptothecin has been described as 'the most promising anti-cancer drug ... ever ...found'. It is one a range of drugs that inhibits chemical reactions inside the body leading to reduced tumor growth.

Its complicated chemical structure makes it hard to synthesise in the laboratory, so the main source of the drug is still the Happy Tree (although there are side effects from this drug which artificial preparations may be able to minimise). The market for camptothecin in 2004 was worth a billion US dollars.

The 2011 study concludes that the tree is fast growing and suited to warm, humid regions of Australia such as coastal Queensland. So while there might not be potential for a Victorian industry, we can grow and marvel at this tree in our gardens if we plant wisely.

Planting wisely is how we intend to adapt to climate change at the Melbourne Gardens. Sometimes it means planting new kinds of plants, but it also means thinking about where and how we plant trees, taking best advantage of nooks and crannies such as this idyllic lakeside setting.

Like the Handkerchief Tree of two weeks ago, this odd plant used to be in the family Nyssaceae but is now included in the dogwood family, Cornaceae. In leaf it's not unlike Cornus I guess. In a 2007 piece written for Dave's Garden Jeremy Lucas compares the leaves to those of an avocado, but with 'heavier, pleated veining'. That seems about right.  


Jeremy Lucas tried to track down why it was called Xi Shu (Happy Tree) in China but didn't get a definitive answer. Perhaps it is due to its tall, handsome stature and bright green leaves. Alternatively, as I thought when I started writing this and as a Chinese correspondent suggested to Lucas, the happiness may be related to curing disease, given it has long been a medicinal tree in China.

And if that doesn't satisfy you, track down the apocryphal story on ChinaHorticulture.net. I don't get it but the legend starts with a thing called Desperate Grass in the Garden of Eden, and ends with singing trees on a desert island. God plays a major role, and Adam and Eve bit parts, but the plants really star. In the end, the singing trees are given the name Happy Trees because wind blowing through them makes a similar (pleasing) sound to wind through the exiled Desperate Grass. Everyone, except perhaps Adam and Eve, are happy.

Note: We featured this tree on Instagram (@royalbotanicgardensvic) and our Royal Botanic Gardens Victoria Facebook page on 28 January 2016, but it's worth (William) telling more of its story and publishing a few more images (all taken the week afterwards). The picture of the banana-like fruits near the top of the post is an exception; it comes from the website ChinaHorticulture.netThis is what our's looked like in mid-February, on their way to pseudobananadom:


Tuesday, 5 April 2016

The somewhat immortal House Leek at work 24/7


In leaf this plant looks so ordinary, so familiar, we barely notice it. But when it sends up this chunky stalk topped with an umbrella of, if not showy, at least curious flowers, you take a second look. I did.

What we have here is a succulent called Sempervivum, probably Sempervivum tectorum. You see it, or one of its relative, all over the place. It's in the family Crassulaceae, which includes fleshy leaved plants, often with leaves tightly packed in a rosette, like this one. The flowers most often rise above the rosette on some kind of stalk.


Sometime ago I promised to blog about Crassulacean Acid Metabolism, or CAM. Many, if not all, members of the Crassulaceae exhibit this special way of converting sunlight into food (photosynthesis). So too do other plants such as fleshy orchids and bromeliads - it's an adaptation to living in places or climates where water is scarce, such as deserts and up in trees.

The basic concept is that the (usually fleshy) leaves and stems act like a battery, capturing carbon dioxide at night when it's safe to open the pores (stomata) in the leaf. The carbon dioxide is combined into a chemical call malate, which can be stored inside the cell (actually in the 'vacuole'). The plant then strips carbon dioxide from the malate during the day - when the sun's energy is available - to build the sugars needed by the plant to live and grow.

The benefit to the plant of this time shift in the two parts of photosynthesis (other plants take up and fix carbon dioxide during the day) is less water lost during the day. Opening your pores to take in carbon dioxide is always a compromise in a hot, dry environment since water will be lost through evaporation.

So our Sempervivum is adapted to life with limited water. In our garden it gets plenty but it does mean that we can forget to water it occasionally, or take a holiday and return to find it alive. This accounts for one of its common names, Live Forever. In fact it's botanical name means the same thing: always alive.

Yet while the plant as a whole may always be alive, once a rosette flowers, after a year or two, it dies. By that time there will be plenty of offsets around the base so the thing lives on*.


If this species is indeed Sempervivum tectorum, we have access to more obscure common name. Tectorum means 'of roofs', and according to Wikipedia, this species (and quite possibly others) were apparently planted on the top of houses to 'ward off fire and lightening strikes'. This is celebrated in the common name House Leek (note the spelling, and therefore reference to the onion relative it might resemble a little in flower rather than holes in the roof).  There are also other names such as Jupiter's Beard that may relate to the plants connection with thunder and storms, in a good way.

If you look closely at the flowers in my pictures you can see they in their 'male phase' with active stamens producing pollen but the female bits curled up and non-receptive. This way the plant is more likely to avoid self-pollination, a topic I seem to return to quite often in this blog (e.g. the Monkey Flower). You can also see there are lots of floral parts - a dozen or so petals, about twice as many stamens and who I reckon a dozen female bits. Plenty going on, day or night.


*Or so the theory goes. As it happens, a month or two after taking these pictures, our entire clump has succumbed. Bad botany or bad plant husbandry? 

Tuesday, 29 March 2016

Handkerchief tree in full blow


Appropriately, as Christians and others celebrate Easter, today my talking plant celebrates Père (Father) Armand David, a missionary who himself became converted - to become a naturalist - during his time in China. He was the first European to 'discover' the Giant Panda and has numerous animals and plants named after him. The plant most often associated with his name is the Dove Tree or Handkerchief Tree, Davidia involucrata.

Jane Kilpatrick tells his story, and that of other European missionaries who botanised in China, in her recent (2014) book Fathers of Botany. David was born in the south-west of France in 1826 and Kilpatrick says he credits his Basque upbringing for his stamina.

The Dove Tree was found by David in 1869, in the Baozing County of Sichuan Province in central China, where he also found the Giant Panda. Both live in mountain forests, the Dove Tree between 1100 and 2600 meters above sea level.


The flowers are small and clustered together, but like a few other plants I've mentioned, they are associated with large showy 'bracts'. There are two bracts in this case, each resembling a handkerchief or something more romantic. Irish botanist Augustine Henry saw a single tree in flower in 1888 and says it was 'one of the strangest sights… a solitary tree of davidia in full blow…waving its innumerable ghost handkerchiefs'.

A decade later, noted English plant collector, E.H. Wilson, described the bracts blowing the breeze as resembling 'huge butterflies or small doves hovering among the trees'. In fact it's said (Seamus O'Brien, In the Footsteps of Augustine Henry and his Chinese plant collectors) that to see this plant in nature was the sole reason Wilson made his first visit to China.

The first illustrations of the flowers were from pressed, dried specimens, and the bracts were shown sticking upwards. In fact, of course, they flutter downwards like someone waving a white handkerchief.

You'd think these bracts have something to do with attracting pollinators to the inconspicuous flowers, although perhaps not biped mammals. The Arnold Arboretum in the USA has helpfully done the research, concluding that the bracts are part umbrella (shielding the flowers to keep pollen dry) and partly sex appeal (attracting insect pollinators). They even help support the tree when young, producing sugars from sunlight (photosynthesis), before they turn from green to white.



This is an odd plant, often classified with the Tupelo, Nyssa sylvatica, and Happy Tree (more on the latter in two weeks time...), in the family Nyssaceae. (The Tupelo has beautiful autumn colour, always attracting attention in April in the Melbourne Gardens.) In the past the Dove Tree has been also placed in its own family, the Davidiaceae, but the latest molecular classifications include the family Nyssaceae within an expanded Cornaceae (some species of which have four large petal-like bracts around the flowers, not dissimilar and often as striking as the Dove Tree flowers).

Henry (and no I don't know why all the surnames can double as first names) had actually found a new variety of the Dove or Hankerchief Tree, later named vilmoriniana. It had smooth, hairless leaves (apart from a few hairs on the under surface of the veins) compared with the downy under surface of the leaves collected by David. This variety is now the most common in cultivation, particularly in cooler regions.


While we don't distinguish on our census what variety we have in Melbourne Gardens, the leaves of the one specimen I could find don't have a hairy under surface so I'm presuming they belong to variety vilmoriniana. And if I enlarge the pictures I took in the garden of Tieve Tara, at Mount Macedon, in October 2014 (adorning this post), again I don't see any overt hairiness.

That's settled then. We can now just enjoy the flowers in full blow.


Tuesday, 22 March 2016

Hot on the trail of excess petals in the Bishop's Hat


And while we are counting petals (see last week's post) I have another corollic conundrum (assuming you'll allow me to use the term 'corollic' as an adjective for things pertaining to the corolla, the collection of petals in a flower). It relates to our latest chilli plants, gifted to us by Neville Walsh, and in flower here in the middle of January.


The plants are rather tall for a chilli, getting up to two metres or so (ours only hit one metre), with a fruit that is unusually shaped - like cap of some kind (but more of that later) - and flavoured - the basal part is relatively mild but sweet, but the top carries a decent (but not overwhelming) punch.

Tracking down the correct name for this chilli was, as it is for lots of garden favourites, tiresome. I think I have it sorted now though, thanks mostly to a Suburban Tomato post and to Natureman, responding on the UBC Botanical Garden Forum.

What I'm illustrating here is what we often call Scotch Bonnet in Australia, but elsewhere and sometimes in Australia too, Bishop's Hat, Bishop's Cap or Bishop's Crown. Scotch Bonnet in the UK, as I can attest from a particularly volatile sauce I bought from a Brighton (UK) chilli shop a few years back, is a quite different thing: it's a very hot fruited cultivar of Capsicum chinense, the same species responsible for the habaneros. Our fruit gets eaten by possums when red and ripe (yes a strange thing for us to do, grow food solely for wildlife), but here they are juvenile and green on the last day of January (two weeks after the flower photos).


The Australian Scotch Bonnet, or universal Bishop's Hat, is a cultivar of the species Capsicum baccatum, even though occasionally you see it referred to Capsicum annum. These two species are easily separated if you have flowers: those of baccatum have yellow or green spots, those of annum (and for that matter chinense) are entirely white or off-white.

So with its spotted flowers and bonnet/hat-shaped fruits that are not overwhelmingly hot in flavour, our cultivar belongs to Capsicum baccatum a South American species. Wikipedia agrees and says it's a cultivar of variety pendulum, providing a few more common names, such as peri peri (although not the 'real', and again hotter, peri peri which is a cultivar of year another species, Capsicum frutescens, another entirely white-flowered species).

According to a key at Jungle Rain the varieties are distinguish on the basis of their flower spot colour, yellow for variety pendulum and pale green for variety baccatum. Our plant has flowers with spots that could be described as either colour really so I'll stick with the straight species assignation. All up, tiresome to untangle but reasonably reasonable.


On the other hand, the number of petals on each flower seems entirely unreasonable. On our bush at home there are five, six or seven, in relatively equal proportion. I thought Capsicum, like all members of the family Solanaceae (think potatoes, tomatoes, Deadly Nightshade and Kangaroo Apple), had five petals. Here for reference is the flower of a Thai Birdseye chilli plant from last year, with five, entirely white petals (a cultivar of Capsicum annum).


When I checked a reliable sources (such as Vernon Heywood's majestic Flowering Plant Families of the World and David Mabberley's The Plant-Book) I find that while five is the most usual number of petals in a plant of this family, they do vary: Heywood says four to ten, Mabberley four to six.

Well, our flowers have five to seven petals. I can't recall ever seeming more than five on the entirely white-flowers species of Capsicum we've grown before, or for that matter on tomatoes or potatoes. But then again, I wasn't really looking, until now.


Notes: Lynda Entwisle noticed and commented on the odd (and even and odd) number of petals on these flowers, prompting this post. All pictures are from our backyard (the single picture of a white-flowered Thai Birdseye is from a couple of years ago, with the Bishop's Hat flowers and green fruit from January this year).

And a bonus picture, of a fruit picked green and reddened up inside, photographed a couple of weeks ago...



Tuesday, 15 March 2016

One-petalled flower not really


Begonia guru Peter Sharp says the so-called 'Rex Begonias' are usually grown indoors although he has seen them grown successfully in gardens (Peter wrote the book from Sydney and is now in Tasmania, offering up two quite different prospects for these plants I'd suggest). We have one of them, growing sort of outdoors in Melbourne, in a pot.

It's a few weeks since our plant flowered but talk of the Begonia Festival at Ballarat Botanical Gardens over the weekend, reminded me of its odd flowers. As mentioned last time I was diverted by a Begonia, the genus is usually split into eight informal groups.

One of these groups contains begonias with an underground stem (rhizome) rather than a tuber, and with a recent ancestor (prior to breeding) called Begonia rex from India. The cultivar we are growing (photographed here) may have a little of another species, Begonia mesoniana (the Iron Cross Begonia), in its family history but this post is not about taxonomy (that is, I haven't confirmed its identity...). With its distinctive habit and coarse hairy leaves I'm presuming it nestles somewhere near Begonia rex. and is therefore a member of the rather sinisterly named Rex Cultorum Group.


With a light sprinkle of water each morning our Rex devotee grows quite nicely on our front porch, flowering happily in January and February.

Most growers don't grow begonias for their flowers. In fact the usual advice is something like 'cut the flowers and allow the plants energy to go into growing the leaves'. If you ignore this advice you'll be at least mildly intrigued by what looks like a single petal in some flowers. Which is very odd.


Begonias have separate male and female flowers, both on the same plant and mostly both within each terminal cluster. In our plant there were only female flowers open when I took the first photographs (11 January; above and top of post), and the male flowers (without the large deep red ridged structure so apparent in this picture) only in bud. Two weeks later (below) it was all about the male flowers, although with a few females still waiting to open later (see the bud heading downwards to bottom left).


The flowers are described as having four or five 'sepals' and no petals. Not one or two, none. But...although the sepals in most plants are usually the outer ring of greenish bits, in begonias they usually more colourful and look pretty much like petals. This is why they are often described as petaloid sepals.

In those blousy blooms you see on tuberous begonias at places like Ballarat Botanical Gardens, I'm presuming the anthers are all converted into petal-like bits as they are in Hellebores. This gives the impression of a profusion of petals.

In nature and in many other species there are just four or five of those colourful floral bits. Sometimes they look the same as each other but you can also get two plate-like petaloid sepals, and two narrower and smaller segments. Oddly, in this particular case the female flowers have two big ones and just one of the second tier. So that's three in total unless one is very tiny (which it may be). That's almost as odd as having one petal!

The male flowers are more conventional, having two outer parts and two of the petaloid sepals inside. The yellow pom pom is of course a cluster of stamens tipped with yellow anthers (full of pollen).

Searching the web I see there are other examples (but not many) of the female flower morphology. One example is the Chinese species Begonia fimbristipula, whose leaves are used for making a tea-like drink. So it's not just a odd reaction by the plant to the Melbourne porch climate.


The pot, moved out of the porch, for its portrait. 

Tuesday, 8 March 2016

Frosty leaf a misnomer but neohymenopogon apt


I try not to proselytise on behalf of botanical names and their derivations. I find nomenclature interesting because I'm a taxonomist and that's part of what we do, but it feels like a lazy way to generate a story. Sometimes, though, you just have to ask what's going on with a name.

A case in point is Neohymenopogon parasticus, a generously flowering epiphyte from China and thereabouts. In January we had one in full bloom in the nursery and one just finishing up in the Southern Chinese collection beside the Ornamental Lake.


Starting at the start, neo means 'new'. Hymen is a membrane of some kind, as most of us know. Pogon is a beard, as in Leucopogon, the Australian heaths with hairy petals. So, all up, the new membranous beard.

Now, often 'neo' is added to another name to designate a group of plants a bit like another, or perhaps in a new area, or sometimes to simply fix up a 'bad' name (that is, one that has some technical problems and can't be used). So this genus might be a bit like something called Hymenopogon, or it might be what used to be called Hymenopogon but can no longer be done so.

It seems to be the latter. When Nathaniel Wallich gave this plant the name Hymenopogon in 1824 he was apparently unaware of the same name, more or less (Hymenopogum), being used in 1816 for a moss. Because we taxonomists agree that who so ever names a plant first is to be respected and their name treasured for all time, that name or its 'orthographic' variant must remain attached to the moss.

In 1981 this problem was fixed by Sigamony Bennet, by publishing the new name with a new beginning about newness... Neohymenopogon. So that bit's sorted. As to the membranous beard, that I expect refers to the hairy petals you can see in these pictures.


The species name is pretty obviously suggesting it's a parasite. That is, it lives off another organism by some means. I don't think our plant really is a parasite and certainly we grow it without any host. However it might be a reference to where it grows in nature, often attached to trees above the ground. 

This species (see even I want to avoid using that elongated name) is in the large, mostly tropical plant family Rubiaceae, diagnosed generally by the pairs of leaves with tiny pennants (called stipules) between them. You can't see much of that in these pictures but the occasional frost-covered leaf is pretty cool.


This distinctive foliage is found below a clusters of flowers, and (other) botanists describe it as a petaloid bract. In this case it hasn't made much of an effort to look like a petal, apart from matching the colour, so perhaps a better name would be a foliaceous bract. Similar leaf-like appendages adorn the flowers of other plants, such as the four species of another tongue-twisting genus, Schizophragma, a climbing Hydrangea relative from the same parts of the world (we have a Japanese species, Schizophragma hydrangeoides, growing between the Rose Pavilion and the Ornamental Lake).

There are three species of Neohymenopogon, but only parasiticus grown in Melbourne Gardens. It was discovered and described by Nathaniel from the Himalaya in India but its natural range extends into China. The other two species also come from the Himalaya region. While Neohymenopogon parasiticus only occurs down to 1200 metres above sea level in its native habitat, it seems happy enough at ground level here in Melbourne, not requiring mountains or a plant host to hoist it skywards.

Tuesday, 1 March 2016

Girls who are boys, a botanical blur


"Girls who are boys..."

The Brit-pop-indie band Blur went on to sing about girls who like boys to be girls, and so on. It's from a song (Girls & Boys) written in the 1990s, in response to the rampant promiscuity observed at one of those European island holiday resorts.

Promiscuity is a good thing for most plants. A successful life usually means having sex with as many partners as possible. Charles Darwin put it more soberly when he said (in reference to orchids, about which he was obsessing a the time) nature abhors perpetual self-fertilisation.

Fertilising yourself is better than no fertilisation, but to be an evolutionary success as a plant it's best to avoid it when you can. While most flowers have both boy and girl bits, they usually make sure they mature at different times. There are backup mechanisms if that doesn't work but a safer way is have separate boy and girl flowers. This is more like the way we humans do it, although the same plant can have male and female blooms on the same individual.


Sometimes, as with Ternstroemia gymnanthera, things are a little blurred (to milk the punny music connection). The False or Japanese Cleyera (Cleyera being a genus in the same obscure family Pentaphylaceae - but more of that later) has plants with either male flowers (above), or flowers that look bisexual (below). All flowers have five white petals and plenty of boy bits - the stamens.


When you look closely at these two pictures you see obvious differences. The male flowers, as is often the case for 'unisexual' flowers, have rudimentary but inoperative girl bits (you can't see these in the picture). They produce lots of pollen but no fruit and seed.

The flowers that look bisexual seem to have it all but compared to the male flowers the stamens are much smaller and shrunken back below the swollen green ovary. It turns out the girl bits work in this flower but the boy bits don't, or only hardly so.

Taiwanese study demonstrated this nicely, showing that the pollen were differently shaped in the two kinds of flowers and when cultured in sugar solution only the pollen from male flowers produced pollen tubes (needed for fertilisation). Some of the misshapen pollen in the apparently bisexual flowers became activated a little during the study but none formed proper pollen tubes.


The net outcome is plants with functionally male flowers and plants with functionally female flowers. We have both in the Melbourne Gardens, as you can see from my pictures taken in mid-January this year. The red berries, if and when they form, will only be on the latter of course. Given the sweet perfume of the flowers and their popularity with honey bees (as illustrated above) I expect a nice crop in late summer.


If you are wondering where this Ternstroemia thing fits into the plant kingdom, then you are among friends. The flowers look a lot like a Camellia, particularly something like the tea plant, Camellia sinensis. The leaves are a little like Franklinia, even reddening up occasionally as they do in that genus. With both those genera being in the family Theaceae, Ternstroemia was for a long time considered part of that family (in fact our signs in the Royal Botanic Gardens Victoria still reflect that legacy).

Nowadays, with the latest molecular evidence to hand, the False Cleyera is classified with the real Cleyera in the family Pentaphylaceae. I don't know much more about the family but it's mostly tropical. Ternstroemia itself has about 85 species, with one (Ternostroemia cherryi) extending into Queensland and Northern Territory from New Guinea. The only species in cultivation, and not widely so, is our Ternstroemia gymnanthera (the species name meaning naked anthers, a reference to the lack of bristles on the boy bits) from India through to Japan.

So, girls and boys, things are not always as they seem.