Tuesday, 6 December 2016

Do fungi get the winter blues in D?

The modern study of genetics and DNA has shown that mushrooms (and other fungi) are more closely related to us humans than they are to plants. Here you see a mushroom and a mycologist (a fungal expert, in this case Dr Tom May) getting to know each other in the Melbourne Gardens of Royal Botanic Gardens Victoria.

This relationship makes some sense because fungi don't produce sugars using sunlight (i.e. they don't photosynthesise), their cell walls contain chiton rather than the cellulose found in plants (and chiton is found in the hard outer layer of insects), they contain proteins similar to those found in animals, and ... they can produce vitamin D.

Unlike humans, fungi don't seem to suffer from vitamin D deficiency but perhaps that's because the mushroom medical service is less interventionist. You can find reference to up to 80% of the humans in the USA being deficient in vitamin D. Whatever the real human deficit, vitamin D is certainly needed to allow calcium to be absorbed and turned into bone. Vitamin D is also implicated in keeping your brain healthy and its absence has been linked to various diseases and ailments.

I'll put my cynicism aside, although I'm tempted to put out a call for anyone who has had their vitamin D levels tested and been told they are sufficient. Let's start with the premise that humans need vitamin D for a healthy and worthwhile life, and that they can produce it from the action of sunlight on their skin.

So if you need more vitamin D you can risk skin cancer by exposing your surface to the sun, harvest the livers of cod (allowing them to ferment for a year if you are a traditionalist) or encourage some (edible) mushrooms in your lawn and then (if really edible) eat them. OK, there are few other sources of this vitamin but they are not as interesting.

Back in 2013 that ever reliable source of information, the UK Daily Mail, suggested we place our store-bought mushrooms out in the sun for half an hour to give us a dose equivalent to a tablet or two. Or if you prefer the view of a 'respected Australian scientist', Professor Rebecca Mason, head of physiology at Sydney Medical School, said (also in 2013) three or four small mushrooms left unwrapped on a plate in the 'midday summer sun' for two hours (longer in winter) will produce enough vitamin D for your average humans daily needs.

Another way to create food rich in vitamin D is to allow fungi to 'contaminate' plants. That contamination could through mutually beneficial relationships such as mycorrhizae on plant roots - although presumably the fungi would have to fruit in the open air so that they produced some vitamin D for the sharing. There is some research needed in this area.

Although mushrooms and other fungi produce only one kind of vitamin D - called D2 - medical studies have (apparently) shown that the fungal dose can be as effective for humans as tablets with both D2 and D3. (Vitamin D1 is apparently less common and/or less important, as are D4 and D5.) Cooking doesn't damage the chemicals and may even help in their uptake.

All very interesting and another part of the evolutionary history shared by fungi and humans. What we need now is research into the well-being of those poor mushrooms produced in musty dark cellars.

Images: The plate of edible fungi is from a restaurant in Edinburgh, visited in September 2006. Here is the owner proudly showing me what would end up in my (very nice) pasta dish. I don't know that the mushrooms and other fungal fruiting bodies produced in this region would get much sunlight even when grown above ground.

Tuesday, 29 November 2016

Stachyurus a veil of dubiously sexed flowers

Using my misleading 'from a distance' identification skills I thought I could see a close ally of Garrya elliptica - the Silk Tassal - ahead as I walked through Burnley Gardens in late September. As I got closer it clearly wasn't but I struggled to remember what this plant was called, even its plant family (which can be a good way to narrow down the options, sometimes).

It's a species I do know but as Stephen Harris, from University of Oxford, tells us, this is one odd plant. So odd that its genus, Stachyurus, requires its own family, the Stachyraceae. In his Horticultural Flora of South-eastern Australia, Roger Spencer describes the dangling flowers of the Spiketail as 'looking like ears of wheat'.

Four of the eight species are found only in China (+/- Taiwan I should add), including this one, which I'm pretty sure is Stachyurus chinensis. In nature this species is widespread at the edge of forests, and like that other Stachyurus species found sometimes in Australian gardens, Stachyurus praecox from Japan, it begins flowering before the leaves appear.

Compared to Stachyurus praecox (and other) species, Stachyurus chinensis has rounder leaves, a longer chains of flowers, and the male and female bits held within the petals. Although Christopher Grey-Wilson and Phillip Cribb in their Guide to the Flowers of Western China note that sometimes these two species are considered one and the same.

The species name 'praecox' refers to its early flowering, making it a good indicator of sprinter. This species, from China, flowers later and was powering through to sprummer (mid-spring) when I saw it in late September.

Originally Stachyurus was included with Camellia in the Theaceae, and later considered to be close to the Hamamelidaceae (with things like Witch Hazel, but also the Winter Hazel, Corylopsis, which has a drooping chain of flowers) but it turns out to be more like the succulent with rotten-meat-smelling flowers, Staphylea, and an odd little family from middle Americas called the Crossosomataceae.

Anyway, a very 'special' group of plants, and the genus name 'stachyurus' refers - in ancient tongues - to the most distinctive feature of the flowers, their arrangement into a dangling tail. 

In nature, apparently, flowers can be female-only or have fully functioning male and female bits. However even the ones that look like both bits are working and active, produce mostly pollen and behave like males. So out in the wild bees and flies are essential for cross fertilisation and seed production.

The plants I observed in Burnley Garden seemed to have flowers with juicy male and female bits, and then further back up the flowering tail, fruits that seemed to be setting.

All that hidden within a veil of flowers caught in the morning sun.

Tuesday, 22 November 2016

Sundews frightening, astounding and beautiful

Back in 2010 I posted a note about a study showing that sundews don't worry too much about where they position their flowers (although there is the potential for them to eat their pollinators, this doesn't seem to be big problem). In that post I included a few pictures of sundews but, curiously given the topic, none with flowers.

I followed up with some quotes from Charles Darwin about these glistening insectivorous marvels, including his confession that he was 'frightened and astounded' by his results and at that time he cared 'more about Drosera than the origin of all the species in the world'.

Today I redress the image imbalance with some pictures of a rather common sundew in these parts, Drosera aberrans (previously known as Drosera whittakeri, a species now confined to South Australia), in flower. There are 90 species of Drosera in the world, with more than half (about 53) native to Australia. Drosera aberrans has simple ground-hugging rosette of green, orange and/or red leaves.

This species of sundew is constrained in its flower number (few rosettes produce flowers and when they do, there is one open at a time) but not so much in flower size (this white, dinner plate is big enough to almost shade the whole plant when open).

You almost always find extensive clumps of rosette because its favoured means of reproduction is to send out a 'stolon', which can arise from the middle of the rosette, which will loop towards the ground and burrow into soil nearby to the mother plant.

According to Alan Lowrie and John Conran, in their 2008 paper in Telopea raising aberrans from variety to species level, a colony of 'several hundred' rosettes may only produce a 'few flowers per season'. That's not true for this colony at Professors Hill in Warrandyte, on the outskirts of suburban Melbourne (in the following picture the flowers are closed, but you can see the many white flecks), and also for a population photographed in VicFlora (with beautifully opened flowers).

Each flowering shoot in the middle or a rosette can produce one to four (or in very fertile soils, up to seven) flowers, with only one opening at a time. This one has two flower buds and I saw up to four.

Inside that lovingly produced flower you can see five stamens. These are the yellow pom-poms on chunky stalks. Bristling among them three styles (the female bits) divided into a hundred or so light green filaments.

All Drosera species have leaves covered in hairs topped by a blob of sugar solution which acts as a glue catch insects. When an insect makes contact with one of the sticky hairs they trigger a response from the plant, with nearby hairs leaning towards prey and the leaf folding in. The sundew extracts nitrogen and other essential chemicals from the insect to help it live in nutrient-poor and often waterlogged soils. 

While not to a tiny insect perhaps, these are beautiful plants - glistening red, orange or green. According to Lowrie and Conran, the leaf colour is nothing to do with light exposure and you often find green-, orange- and red-leaved forms growing together, right next to single-colour colonies. Sun or shade, red or green. However plants do tend to become red with age.

These pictures were taken in mid-August and the Drosera aberrans flowering season is July to September, although mostly in August and September, making it one of my 'sprinter' flowers (the wattles that characterise sprinter often start blooming in late July).

Tuesday, 15 November 2016

Grevillea looks pretty like a wattle

I thought, from a distance, well here's a pretty wattle. Close up it revealed itself as a pretty member of the Proteaceae family and, as it turns out, a Grevillea.

Why do these grevillea flowers look like a wattle bloom - at least from a distance? (Or perhaps, why do some wattles look like this grevillea?) Probably because the colour and arrangement of flowers are attractive to the same potential pollinators.

In the east, at least, the flowers of the Zigzag Grevillea attract lots of birds and insects. Yellow flowers are generally associated with insect pollinators, and it's likely they appeal to the same beetles, wasps and bees as wattle blossom. As with wattles, birds and mammals may also assist. 

Grevillea flexuosa is on the list of endangered species in Australia, and only known in the wild from rocky hills to the north-east of Perth. It was once thought to be very close to extinction but I gather an additional population discovered in recent times has raised its survival chances a little.

I haven't seen it in its natural habitat but these pictures are from a rather wet morning in Western Victoria in mid-September. The Zigzag (or Tangled) Grevillea is forming an attractive hedge bordering part of Royal Mail Hotel in Dunkeld, at the south of Victoria's Grampians range. 

You see the species here and there in gardens with climate and soils suitable for growing Western Australian wildflowers, such as Dunkeld. Although I'm presuming most garden grown plants of Zigzag Grevillea in the East are grafted onto Silky Oak (Grevillea robusta) rootstock or one of the tough Grevillea hybrids. They certainly do well in Dunkeld, although it does seem to be a place where you can grow lots of Western Australian beauties (see below). 

Thanks to Swiss botanist Carl Meisner, this striking species became a Grevillea the year before a patch of land beside the Yarra River in Melbourne became a botanic garden (1846).  It was originally named Anadenia flexuosa by English botanist John Lindley, in his 1839 'A Sketch of the Vegetation of the Swan River Colony'. Lindley named it flexuosa to remind us of its 'curious zigzag leaves'. 

Carl Meisner moved the whole genus Anadenia - established by Scottish botanist Robert Brown in 1810, six years before Sydney's botanic garden was established - to Grevillea.

You do see this species described as prostrate, getting to only 30 cm high, and with pink flowers, but presumably that is a misidentification. FloraBase - the authoritative guide to the Western Australian flora - confirms Grevillea flexuosa as having the same form as we see in cultivation over in the east, reaching two metres or so and with flowers very much creamy yellow.

Not much more to say on this one so I'll finish with few more gorgeous Western Australian blooms from the Royal Mail Hotel garden at Dunkeld, adding to my rather fawning post of seven years ago. These are all in the the same plant family as Grevillea - the Proteaceae - except of course the wattle (Acacia denticulosa) at the end for comparison with our Zigzag Grevillea...

Tuesday, 8 November 2016

The Irishman's beautiful South African plant

While we are on South African plants (last week it was yet another Salvia), here's an old favourite with a melodious name - Mackaya bella. It might be a greeting from your gorgeous Italian girlfriend, or perhaps her name.

The 'bella' part is clearly are reference to this plant's beauty (you'll recall of course that rather attractive seaweed, Entwisleia bella), while Mackaya celebrates the botanist James Townsend Mackay, founder of Trinity College Botanic Garden in Dublin and author in 1836 of Flora Hibernica (Hibernica being Ireland). 

While I don't think Mackay has anything to do with South Africa or this plant, it was named after him by compatriot William Harvey, who collected plants from the Cape in the 1830s, writing a flora of the region with Otto Sonder (the gentleman who sold my predecessor Ferdinand Mueller 300,000 or so specimens from his massive herbarium).

So as with Entwisle's beautiful alga, this name can be read as Mackay's beautiful shrub. Also like Entwisle's alga, there is only one species in this genus. Although, unlike that algal beauty, there are many more genera in Mackaya's family, Acanthaceae, such as the Oyster Plant (Acanthus mollis).

The beauty in this plant, also called the Forest Bell Bush, is mostly to do with its flowers. Out of flower it's a compact shrub or small tree with quite nice dark-green leaves but nothing to earn the epithet bella

A curious, but perhaps not particularly beautiful, characteristic of these leaves is an ocassional 'hairy pocket' on the undersurface, where the veins in the leaves connect. This is a picture I took back in my office using a small magnifying lens attached to my phone...

It's actually a little dimple, which you can see poking through as pimple-like projections on the upper surface in this next picture.

I'm presuming these pockets provide homes to insects that on the whole are beneficial to the plant. Certainly the flowers attract plenty of insect visitors, including most notably in South Africa, the Blue Pansy Butterfly.

And it's the veins that deserve mention here as well. In the flowers, the beautiful flowers, the petals like a thin parchment or membrane etched with purple veins.

They say, and it seems to be true in Melbourne Gardens, it does best in shade but flowers more with sun. It's clearly a tough plant and one that we use a bit as a filler around the botanic gardens, but odd that it isn't in more gardens. Perhaps that's because it's considered 'rather old fashioned'. Climate change may well bring it back into fashion but could also encourage its potential as an environmental weed (it is already one in New Zealand).

Tuesday, 1 November 2016

Dead flowers still firing salvos

To my surprise, given I hardly noticed them until I worked at Kew Gardens between 2011 and 2013, Salvia is becoming a Talking Plants favourite. I put it down to a mix of beauty, oddity and pervasiveness. They are not quite everywhere but you do find them here and there.

Today's salvo about salvias is all about one that caught my attention in late August, growing in our border beside the Government House fence. Walking past it in early September I thought the flowers must have been long finished, or perhaps we'd had a frost in Melbourne Gardens despite our climate-change induced almost total lack of them these days.

This is the unassumingly named Brown Salvia, or sometimes Beach Salvia, Salvia africana-lutea. And it does indeed have brown flowers - from a distance looking like like a flowering Gorse Bush past its prime.

When you look closely there are still new flowers being produced but all open flowers are rusty orange or brown, and apparently dry and papery in texture. Dead looking. 

All emerging buds, though, are pale yellow. Alive looking.

So, are the brown flowers alive in the sense of helping the plant to reproduce? Are they attracting pollinators, firing off pollen and receptive to incoming germplasm, or are they the dregs of something that happened back at the bud stage?

It seems the answers are yes to these questions. I couldn't find any yellow coloured flowers open to the world so all the action happens after they turn brown. And while brown, the flowers produce 'a lot of sweet nectar which attracts bees and moths, and acts as an essential food supply [in it's homeland of South Africa] for sunbirds'. Brown Salvia is also host plant for various butterfly species, including in Melbourne this unassuming white one.

In terms of aesthetics, the layer outside the petals (the bits that turned from yellow to brown), the calyx, turns papery and becomes more arousing than the dead-looking flowers - presumably this time to seed distributing animals as well as the odd-plant-enthusiast. This next picture (taken in mid-September) shows the calyx turning red as the ovary in the middle develops into a fruit, and the next (taken in mid-October) has the fruits swollen to pea shape and size.

The species is also grown for its aromatic foliage. To me it has a soft, mildly minty, cut-grass smell. Apparently this is an attractive odor and the dried leaves end up in tea and potpourri.

A selection from the stunning botanic garden in Cape Town, Kirstenbosch National Botanical Garden, is sold under the name of Kirstenbosch Golden Salvia (Salvia africana-lutea 'Kirstensbosch'). It is apparently 'more vigorous ... and often grows larger' than the typical wild form.

In South Africa Brown Salvia clings to the edge of the Cape, sometimes growing on coastal sand. Hence the name Beach Salvia, as well as Dune Salvia and, in Afrikaans, Bruin of Sandsalie

Tuesday, 25 October 2016

Mouse eating plant in unspectacular flower

I have little interest in rodents eating plants with unattractive* flowers, but I'm intrigued by plants that eat mice, whether or not they have showy blooms.

In this case the plant is Nepenthes truncata, one of the world's bigger pitcher plants. The mouse is a house mouse but that's not the point of this post. Let's just say the pitchers on this pitcher plant are large enough to - and have been proven to - catch a mouse. Whether the plant really wants such a large mammal in its digestive system is unclear.

We grow a single specimen of Nepenthes truncata in our dinky Tropical Glasshouse at Melbourne Gardens. It's a large plant, many years old, and in early September it was in full flower.

Not a flower to brighten a room perhaps but you might think at least we will soon have fruits, and seeds, and possibly a nursery fully of baby pitcher plants. Well, that isn't going to happen. Take a close look at these flowers and you'll notice they seems to consist mostly of a brain-like yellow sphere on a short stalk. Those yellow bits are the anthers, containing pollen.

What's missing from these flowers are the female parts. To find those you need another specimen, and the right kind of other specimen, of Nepenthes truncata. This species, like all Nepenthes, has either male or female plants, and not both. Great for cross-pollination and encouraging genetic mixing and diversity, but rubbish for horticulture.

That said, you'll find this species relatively commonly in a carnivorous plant enthusiast's collection. That's presumably because seed is readily available, even though hard to move between countries due to the constraints of CITES - the Convention on the International Trade in Endangered Species of Wild Flora and Fauna.

The reason for the CITES ban is (as Carlo Ballistrieri from New York reminded me when this story was first posted) because trade in an organism could lead to the species becoming rare and threatened, or more so, in its natural habitat.

This species is already rare in nature, growing naturally only in lowland (230-600 metres above sea level) forests of north-eastern Mindanao, in the Philippines, where it scrambles through jungle vegetation. It was named from two fragmentary collections and is still poorly known in the wild, supporting its listing as Endangered in the Red List of flowering plants.

Our plants are flowering well, if not attractively or successfully (in terms of the reproduction), but the mature pitchers are now fading. Once the plant has got over it's unfulfilled flowering, it can reinvest in the new pitchers just starting to form on the tendrils at the end of its younger leaves.

* I'm sure Hervé (a Parisian botanist) won't mind me repeating this short exchange we had by Twitter today (25 October 2016). He is quite correct!
.@TimEntwisle unspectacular is a big claim! These flowers look pretty amazing and very unusual to me!
@hsauquet_upsud It's amusing you should say that. Each time I look at the photo now I agree! In the glasshouse they looked rather plain...

Tuesday, 18 October 2016

Wowed by weeds in shady cemetery

A few weeks ago garden historian Helen Page took my family for a walk through Boroondara General Cemetery, in Kew (Melbourne). My son and daughter-in-law were visiting from Sydney and we thought this might be a quintessential Melburnian outing - well, we'd done the coffee joints and restaurants.

Helen has been part of a revival of this first garden cemetery in Australia. Until she got there the number of trees was dropping each year, as they died or were removed. Tree numbers have now more than stablised and the 'garden' is taking over from the 'cemetery'. Soon there will be no new burials - even now it's just family plots and ashes associated with the mausoleum and rows of roses.

While the trees are impressive, including lots of mature and unusual cypresses (one being this only specimen of the Golden Funeral Cypress - Chamaecyparis funebris 'Aurea' - in Victoria), I was diverted by the weeds.

Fields of South African Gazanias and Poppies were looking good, as was Rosemary rampant over decaying tombstones and tombs. I was falling in love with the flecks of Fumary (Fumaria) flowers, and the occasional eruptions of Peruvian Bluebell (Scilla peruviana; including an occasional white-flowered variant). Helen is OK with Gazania, and the big bricks walls should contain it's spread a little, but would like to clip and contain the Rosemary. For the Peruvian Bluebell (below), she has little time.

Incidentally, I mentioned this species back in August, explained it apparently inexplicable name, given it is native to the Mediterranean, in a recent post. However I failed to mention then that it is an occasional weed of native bushland in western Victoria (persisting from old properties and spreading locally).

Apart from the misleadingly named bluebell, Helen recognises the appeal of this ragbag collection of the world's tenacious species, and if she has her way some will remain as a colourful and respectful ground cover while specific areas are returned to native grasses and others to more formal plantings.

Boroondara Public Cemetery was apparently the first garden cemetery in Australia. The first grave was dug and filled in 12 March 1859 - 13 years to the month after the Botanic Gardens began in Melbourne. In fact the Director of the Botanic Gardens, William Guilfoyle, had a hand in a small part of its landscaping.

In 1907 Dr John Springthorpe finished building the above memorial and garden to the memory of his wife Annie, who died during the birth of their fourth child. The building was designed by Harold Desbrowe Annear assisted by Springthorpe but the original landscape around it was design by Guilfoyle. That landscape has changed over time and now is little more than a few trees of mixed health. For more on the memorial and garden see this post by Janine Rizzetti.

As Rizzetti points out, Dr Springthorpe doesn't actually name his wife on the memorial but does wish us all to note that she was born on 26 January 1867, married on 26 January 1887 and buried 26 January 1897. Australia Day, or Anniversary Day as it was known at the time, defined and disrupted Annie Springthorpe's life.

Her memorial was described by the The Age (in 1933) as 'one of the most beautiful and most costly in the commonwealth'. It took ten years to build and cost between £4,500 and £10,000.

There are other noteworthy graves, gravestones, memorials ... and trees. River Red Gums (Eucalyptus camaldulensis) seeded from remnants outside the wall were some of the first trees to feature in this 12.5 hectare garden cemetery, named (as is the local Council area) after the local Aboriginal word for 'a place of shade', boroondara.