The mace pagoda: phoenix of the Cape

Adderley Street Flower Market, early 20th century.

One morning in 1847, German botanist Karl Zeyher stopped at Cape Town's Adderley Street Flower Market, like he often did. The flower sellers, as colourful as their wares, were only too eager to show him their latest finds, obtained on long and often dangerous expeditions into the rugged Cape Mountains. Among the bunches of proteas and irises blooming in deep buckets of water, Zeyher noticed something unusual, new. Well, new to science.

Marsh rose (Orothamnus zeyheri).

Slender, woody stems covered in an armour of velvety leaves supported nodding, crimson blooms: it was the marsh rose. He managed to coax the secret of this splendid plant's location from the seller, who told Zeyher he had collected it from the mountainsides above what is now Pringle Bay. In due course, Zeyher located the plant and sent specimens back to Europe. Fellow German botanist, Karl Pappe, gave it the scientific epithet Orothamnus zeyheri, after his colleague. One could argue that it would have been more fitting to name the marsh rose for its original discoverer, but this was colonial South Africa, and botanists of colour, no matter how intrepid, were unlikely to see their names recorded in the annals of history. However, this wouldn't be the last time the flower merchants of Adderley Street would bring something special to the attention of science.

The mountains of the Kogelberg Biosphere Reserve.

T.P. Stokoe amongst the marsh roses.

In 1911, Thomas Pearson Stokoe left his job and his wife and daughter behind in Sunderland, England, got on a ship, and arrived in Cape Town to start a new life as a lithographer for the Cape Times. Inevitably, he became enamoured of the wild places, exploring the mountains to look for new species whenever he could. Upon exploring the fynbos of the Cape Peninsula for the first time, he remarked, "I hesitated to trespass over what I thought was a private garden. Eventually I ventured forward and was thrilled at the sight of so much floral beauty." His desire to seek out novel plants would end up driving him into the hidden peaks and secret valleys of the Kogelberg, clear on the other side of False Bay. And what a place it is. The Kogelberg (Dutch for Cannonball Mountain) towers 1,265 m above the ocean, its ring of severe cliffs simply studded with unique plants. Today, the Kogelberg Biosphere Reserve (a UNESCO World Heritage Site) is home to some 1,600 plant species, of which about 150 are totally endemic to this part of the Cape Floristic Kingdom. The core 320 square kilometres of the reserve harbour more species richness than any other place on Earth of a similar size, including the dense rain forests of the tropics. It's enough to give heart palpitations to any biodiversity fan. Almost every valley and mountainside supports something unique that lives there and only there. Some plants have an entire range limited to a few square metres on a single mountain slope. This place is precious. This place is delicate. This place is magical. Even the genus Protea (the very quintessence of the fynbos biome) is named after Proteus, the ancient shape-shifting sea god. A place of fog and fire, it's easy to imagine the Kogelberg as the home of mythological creatures.

Mimetes stokoei type specimen.

In February 1922, somewhere in the Kogelberg range, Stokoe came across a single specimen of a very unusual and beautiful plant, a tall and elegant member of the protea family. He collected flowering branches as herbarium specimens and sent them to the Royal Botanic Gardens at Kew, where it was described and named Mimetes stokoei, in his honour. Today, this plant is commonly known as the "mace pagoda". However, Stokoe himself always referred to it as his "golden protea". Whatever you'd prefer to call it, something weird was going on. Why was there only one plant on that hillside? Stokoe felt the mysterious and inaccessible Kogelberg, windswept, often wrapped in dense fog, calling out to him. He had to find another specimen. Subsequent collecting trips proved fruitless: it was like his golden protea had never existed at all. On 4 July 1925, Stokoe was perusing the wild flowers sold by the vendors in Adderley Street, when an old friend caught his eye. You guessed it: plunged into a deep bucket of water were the tall and elegant flowering stems of Mimetes stokoei. Stokoe bought the branches from the seller and proceeded to question her about their origins. The seller was less than forthcoming with the information: collecting sites were closely guarded secrets for people whose entire livelihoods depended on bringing the most exotic specimens to Adderley Street. Stokoe was relentless however, and after much persuasion, a deal was struck. With the merchant's supplier as his expert guide, Stokoe set off on an expedition into the Kogelberg range. In due course, the flower picker revealed to him a small stand of Mimetes stokoei, rising elegantly above the other vegetation. It was clear the mace pagoda was scarce; all told, Stokoe and his flower seller friends could only locate ten plants, in two small populations. What was more worrying, though, was that they were all old, mature plants, not seedlings. And it seemed that the plants were in trouble. Senescing. Withering. Dying. By 1959, Mimetes stokoei was listed as extinct.

CapeNature huts in the high valley of the Kogelberg Biosphere Reserve.

Marie Vogts, doyenne of proteas.

The overexploitation of the Cape's vulnerable flora became a growing concern after World War II, and the Adderley Street merchants were no longer allowed to collect flowers from the wild outside of a stringent permit system. In the 1960s, the South African government endorsed active research in the horticultural potential of fynbos, and proteas in particular. Instrumental in this movement towards horticulture as a form of conservation was Marie Vogts. Starting as a lecturer in Botany at the Paarl Teachers' College, she has written seminal works on growing proteas as garden plants and with her expertise and passion for Cape flora has done more to popularize fynbos than anyone. In 1960, she was appointed as a senior professional officer by the Department of Agriculture, and initiated plans for Oudebosch, an exciting experimental protea farm. It would be a permanent collection of horticulturally important species, and also a place of active scientific research. Vogts wanted to conduct transplant experiments: would proteas transplanted from the Cape Peninsula still flower at their regular time, or adapt to the flowering rhythms of their new home? In 1965, Vogts started developing Oudebosch in the high valley of the Palmiet River, deep in the Kogelberg. So how does one start a garden if there's already natural vegetation growing on the land, you may ask? In this case, the vegetation around the plots was clear-cut. Sometimes, however, it's easier just to burn it.

The solitary seedling, 1967.

In 1966, a weird weed sprouted in the Oudebosch nursery, right at the edge of a planting hole. Researchers realized with shock what it was: Mimetes stokoei, resurrected. The only mace pagoda in the entire world. The plant was beyond precious: here was an opportunity to obtain some seed, to save the species. A little protective wooden tripod was constructed around the seedling. This was a mistake. The Kogelberg is known for capricious weather: one morning after a fierce storm, the mace pagoda was found with a broken stem; high winds had snapped it against the very structure put up to protect it. It never even had a chance to flower. The year was 1969, and Mimetes stokoei was declared extinct all over again. So put yourself in Marie's shoes: you've managed to site your experimental farm right on top of the original location of the mace pagoda, all because the old botanists kept that location secret in their own attempt at conservation; clearing and trampling the site during construction of the nursery possibly doomed any other seedlings to oblivion; and when one still managed to sprout against the odds, it dies on your watch. You have such great passion for proteas and for nature conservation, yet in your preservation attempts you inadvertently cause the loss of the rarest one of all. Now: what do you feel? A terrible burden of responsibility? I certainly would, and I think Marie did, or at least accepted the criticism of her peers with good grace. In 1973, a new protea breeding program was started at Tygerhoek in the Overberg, 150 km from Cape Town, and the Oudebosch protea collection was moved there. The Kogelberg was transferred from the Department of Forestry to CapeNature in 1987 and declared a nature reserve. Marie Vogts passed away in 1998, one year before a devastating fire swept the Kogelberg. The fire that absolved her.

The mace pagoda, Mimetes stokoei, in bloom in the Kogelberg in March 2009.

The March 2011 fire creeping across the Kogelberg.

In December 1999, the Kogelberg Biosphere Reserve was engulfed in flames. Four days of hot dry winds fanned runaway blazes, resulting in more than half of the reserve being burnt to ash. However, fynbos has evolved to deal with fire, and exploit its capacity for clearing space and returning nutrients to the soil. Previous wildfires had occurred during winter; the summer monster of 1999 was much hotter. That made all the difference. For you see, Mimetes stokoei is a botanical phoenix, rising anew from its own ashes. It grows very rapidly, towering above the other fynbos, but it has a very short lifespan, perhaps ten years at most. This might explain why Stokoe saw plants that looked past their prime, back in the 1920s. This remarkable plant instead relies on its seedbank, buried in the earth by ants, to start a new generation of plants from scratch. It's as good as if your parents had to die before you could be born (for this analogy to work, pretend that humans lay eggs, okay?) and every generation lived out their entire lives in isolation. What would be a very strange life cycle for us makes sense for plants rooted to a landscape prone to frequent fires. The seeds of the mace pagoda have been lying dormant all this time, until a fire hot enough to awaken them arrived. The amazing thing is that the locality where Mimetes stokoei grows had likely not seen a superhot fire since the early 20th century. Disturbing the soil at Oudebosch during construction of the experimental farm only enabled one seedling to sprout; subsequent controlled burns of the site were never hot enough to awaken any others. But many dormant seeds were still present, under Marie Vogts' nursery, under her feet, waiting patiently. If only she'd known.

In January 2001, reserve manager Mark Johns, out on a burn recovery inspection, noticed 24 unusual silver-leaved plants amongst the lush green post-fire vegetation of a hillside: Mimetes stokoei, the phoenix of the Cape, resurrected by the 1999 fire. The pagodas were growing strongly, rapidly: the first flowering occurred in 2004, with peak flowering reached in 2007. By 2009, the population already seemed to be in decline again, with only five plants left alive. With so much human activity, the incidence of fire in the Cape Floral Kingdom is on the rise. This is not a good thing. Fynbos species don't all deal well with frequent fires, most species instead thriving on a single hot inferno every 15 years or so. On 17 March 2011, a fire started alongside the road to the Bot River Estuary. Since the coastal sand flats are heavily infested with alien plants now, the fire rapidly blazed out of control, spreading into the high valleys of the Kogelberg. The tiny mace pagoda population got torched, and the regal flowers seen in 2009 are gone. For now: we know enough about the biology of Mimetes stokoei now not to call it extinct just because it is cycling between generations. The hottest flames will summon the fynbos phoenix.

Picture credits:

Kogelberg by FrikH

Kogelberg Biosphere Reserve by Ralph Pina
Oudebosch seedling by Fred Kruger

Mimetes stokoei, March 2009 by Nigel Forshaw

2011 Kogelberg fire by Ralph Pina

For much of the research in this story I am deeply indebted to the work of Peter Slingsby and Amida Johns. If you want to know more, purchase their scintillating and wonderfully illustrated biography of T.P. Stokoe here.

Welwitschia: curious cone-bearer of the Namib

This is no ordinary tree trunk.

It was a hot afternoon during my freshman year and I was trying to find my botany professor's office. Sweat running down my spine, already late for organic chemistry, lost in the basement of the Botany building. I turned a corner and came face-to-face with the giant, scalloped remains of a welwitschia, mounted on a pedestal. Clutching the ethnobotany paper I was meant to submit that day, I just stood there, enraptured, mesmerized. It resembled something creepily organic, like Martian fungus, or at least something indecent that had sprouted from the sea floor. Certainly not a tree trunk. I never made it to organic chemistry that day.

Welwitschia mirabilis makes the scorching Namib desert its home.

Not only is Welwitschia mirabilis the solitary member of its genus, but it is also the only member of its family, the Welwitschiaceae. In fact, it is taxonomically so bizarre and so unique that it has been given its own order. The only other species that appear to be (quite distant) kin are the joint-pines of genus Ephedra. Wait, did I say joint-pine?! Yes, I did. For the welwitschia is a short, stunted gymnosperm and bears its seeds in cones, just like pines, firs and spruces. Think about that for a while. This weird tree is found only in the Namib desert of Namibia and Angola, a habitat as different from a dark northern forest as any, the oldest desert on the planet. It is estimated that welwitschias have been growing here for nearly 100 million years, and that they haven't changed much during that time. The welwitschia has many fascinating adaptations that allow it to thrive in this harsh climate. It survives in places where it sometimes doesn't rain for years, subsisting solely on the fog that rolls in from the Atlantic at dawn.

Alien vegetable forms dot the landscape inside Messum Crater, Namibia.

Its short woody stem is unbranched, but grows wider with age to form a crenulated woody bowl that can be a meter in diameter. Like most moisture-dependent desert plants, welwitschias are pretty slow-growing: it is estimated that large specimens with leaves in excess of 6 m long may be more than 1,500 years old. From the margins of the crested stem sprout what appear to be a myriad of strappy leaves. 

A large specimen in the Namib-Naukluft National Park.

Their appearance is deceptive. In fact, the welwitschia only produces two opposing leaves that continue to grow throughout the life of the plant, becoming split and shredded through the action of sand and wind and centuries. The shredded leaves become a trap for wind-blown debris, enriching the sandy soil around the plant and providing shelter for insects, spiders and lizards. Welwitschias have a large taproot to pull moisture from deep underground, and also a network of short fibrous roots near the surface to help them absorb water from ocean fog that condenses on the leaves and rolls to the ground. In a way, these plants engineer their own microclimate to ensure their survival in extremely arid surroundings.

Welwitschia bugs on the cones of a female plant.

As I mentioned, the reproductive structures of Welwitschias are cones, like those of cypresses and cycads. Male and female plants exist separately, bearing different types of cones. Male cones produce pollen, but not in copious amounts like those of wind-pollinated pine trees do. Instead, they rely on insect pollinators to carry their precious cargo to a receptive female plant. The plants are often found crawling with yellow or vermilion coloured welwitschia bugs, Probergrothius sexpunctatis, attracted by the sweet nectar secreted by the immature cones. However, these bugs don't seem to be the pollinators, and other insects have been suggested as the culprits, including flies and wasps. In the unforgiving desert, welwitschias have maximized their chances of survival, especially at the vulnerable seedling stage. When released from mature cones, welwitschia seeds may remain dormant in the sandy soil for several years until heavy rains come to the Namib. Only then does a new generation of Welwitschia mirabilis germinate. All in unison.  

Picture credits:
Welwitschia trunk by Routard05
Welwitschia in habitat by Derek Keats
Messum Crater by intelligentinfo
Naukluft specimen by Joachim Huber
Bugs on cones by Jerry Oldenettel

Tasting fractals: true confessions of a synesthete

Matcha green tea caramels: a volcano of taste.

We were at a bar, discussing the latest lab gossip over flutes of winter ale, when Lyndsay suddenly dug through her bag and presented me with a small, square piece of green candy, wrapped in clear cellophane.

'Our postdoc brought me some of these caramels from Japan,' she said. 'This one's green tea. You should try it.' So I did. An interesting and delicious combination of buttery caramel and invigorating matcha green tea flooded my palate.

'It tastes sort of this shape,' I said, miming a mountain with my hands. 'Sort of...volcano-like. It's rounded, but there's a pronounced indentation at the top where the green tea and the butter caramel intersect.' Both Eric and Lyndsay stared at me as if I'd just confessed to setting a toddler on fire.

'So tastes have shapes to you?' Eric asked.

'Well, kind of,' I said. 'They're more like landscapes than free shapes.' I hesitated. 'But we all have that, right? It's not like I have synesthesia or anything like that.'

'No, Leon, no one else has that,' Lyndsay affirmed. 'No one else tastes shapes.' Eric just laughed, shaking his head furiously. As the first snow of winter started sifting down from pink clouds hugging the town, I started to reconcile myself with the fact that I may have synesthesia.

People with synesthesia show increased connectivity and communication between parts of the brain normally devoted to the processing of different sensory stimuli.

Synesthesia is commonly defined as a neurological condition where stimulation of one of the senses elicits involuntary triggering of another sense. People with synesthesia are dubbed synesthetes, and synesthesia can take many different forms. Some people experience vivid colours when hearing specific sounds (C sharp on the piano sounds golden yellow). Others associate personalities with numbers (4 is such a guarded, introspective number). Still others might associate textures with specific smells (sandpaper smells like strawberries). Much research has been conducted on the cause of synesthesia, suggesting enhanced cross-talk between brain areas usually devoted to separate sensory pathways (see here for an extensive reference list, both peer-reviewed and otherwise). For example, when people who experience coloured-hearing synesthesia are stimulated with spoken words while inside an fMRI, the areas of the brain devoted to the processing of colour information light up like they were watching the psychedelic Star Gate sequence from 2001: A Space Odyssey. The brains of control subjects who don't have synesthesia do not light up in this way, even when they were extensively trained to associate words with specific colours. Science is also beginning to make some progress on the genetic basis of some of the more common forms of synesthesia, with evidence from large-scale genome-wide association studies implicating specific regions on several different chromosomes.

Hearing colours can be quite the space odyssey.

But what about me? My apparent synesthesia has not been confirmed by a neurobiologist, and I've had none of my genes sequenced. Synesthetes are more likely to be left-handed. I'm left-handed. About 40% of synesthetes have a close-relative who also has synesthesia. I...well, I don't know. I've never asked them, and perhaps they, like me, haven't thought it anything unusual and therefore never mentioned it. Also, my kind of synesthesia, morphogeusia (from Ancient Greek morphe, 'form' and geusis, 'taste'), seems to be one of the weirder ones. In addition to taste, it also involves my sense of smell to some extent. I once started to describe the scent of a colleague's perfume as 'very tall, sort of skyscraper-shaped, but with a top that resembles a bisected sphere with indentations...' before trailing off when I saw her raised eyebrows.

Ceylon black tea.

Let me explain what is happening to me. Basic tastes and flavours have pretty basic shapes, and these shapes are not so much felt as seen; they're topography, not texture. All fats and oils elicit the same perception of rounded mounds. Butter is distinctly dome-shaped. This partially explains why those buttery green tea caramels tasted volcano-shaped: it's that mountain of buttery goodness! The taste of rooibos is also rounded, but concave in contrast to the convex dome of butter. Rooibos is therefore bowl-shaped to me, and able to contain other flavours (like the bullets of vanilla), whereas the domed heavy cream of a crème brûlée would go over the top of vanilla. Incidentally, real vanilla is fat and short, whereas artificial vanilla is taller and thinner, more like a rifle cartridge. I had a fine cup of black tea the other day that tasted much like a flight of stairs. Sharp, pungent ingredients like raw onions or wasabi tend to taste like valleys or canyons, and the sharper they are, the more sheer those cliff faces become.

Eggs over easy.

Initially, I took that fact that not every taste seemed to have a shape as evidence that I didn't actually have synesthesia after all. Surely everything must elicit a well-defined topography! But then I realized that it's merely harder for me to see the shapes of things such as eggs and french fries; it's not that they lack landscape, it's just that the topography of that landscape is really shallow. French fries are just shallow ripples, whereas an egg forms a shallow depression, like a dried lake bed. Perhaps surprisingly, the extent of a synesthetic shape does not correlate with my enjoyment of a particular foodstuff. I like both eggs and french fries and don't find their taste one-dimensional, regardless of how shallow and dull their synesthetic features are.

Tart cherries, with a lingering oak finish.

While still an undergrad, I was recruited to a university tasting panel by a friend majoring in food science. Soon my palate was required to evaluate all manner of things, from frozen vegetables to chocolate milk. The sensory evaluators commended my vivid gustatory descriptions for new flavours of potato chips they were developing (though I was careful not to describe them as 'salt flats with interspersed pyramids' or anything similar). However, I'm not a supertaster by any means. Neither do I possess a particularly sophisticated palate. All wine resembles a generic jungle canopy to me. It's as difficult for me to tell one pinot noir from another as it is difficult for me to discriminate between a rain forest from Bolivia and one from Ecuador. Highly complex flavors elicit landscapes that are not very memorable and exceedingly difficult to describe, like the faces of strangers you meet in a dream. What synesthetic shapes did that chilli verde from the other night conjure up? I don't recall exactly, but there was some granularity, I'm sure...

So that's my little personal subjective anecdote about maybe perhaps having synesthesia.

'I'm so happy for you,' a lady in a tea shop said to me the other day, when she overheard me discussing my synesthesia with Eric. 'What a wonderful talent.'

'I'm not sure I'd consider it a talent, as such,' I responded. 'It's not even particularly useful. I'd read about Daniel Tammet, who has high-functioning Asperger syndrome and uses the vivid synesthetic landscapes generated by numbers to recite pi to tens of thousands of digits. I don't have that at all. I'd rather be good at math.'

I didn't tell her about lemons and how they taste like fractals, though. But they do that for everyone, right?

Picture credits:
Matcha green tea carmels from Fusion Sweets
MRI scans from Rouw & Scholte (2007) Nature Neuroscience 10:792-797
Star Gate sequence from 2001: A Space Odyssey (1968)
Stone steps from Steve McCullough
Dry lake bed from Reno Tahoe
Jungle canopy from thaths

Making beautiful science

In about 50 days I'm giving birth to a PhD thesis. I just want to have a beautiful baby. Wish me luck...