Tasmanian Plants

As an ex-student in the School of Plant Science, I was inducted through a training ground, a first year botany laboratory, which bore the name of Winifred Mary Curtis. Then later when my pursuit of botany became more specialized, in the form of looking at bryophytes (mosses and liverworts), I had the privilege of staring down the very same microscope that Winifred Curtis used. But who was this lady centurion who had touched generations of botanists before me, and whose influence is still felt today by participants of the Tasmanian botanical culture, through her forever immortalized magnum opus on Tasmanian Plants, The Student’s Flora of Tasmania.

Richea Xcurtisiae (Hybrid Candleheath)

The legacy of the matriarch of Tasmania’s  botany lives on in the leading botanists of today, most of which were her students or students of her students and her name has also been immortalized in plants such as Richea x curtisiae, Epacris curtisiae and Epilobium curtisiae.

If I should have any regrets of my time in the School of Plant Science, it would be that I never got to meet Dr Curtis. I must be content however for the vast scope of her work; the Curtis award that continues to be bestowed on generations of first year botanists (of which I was a lucky recipient); and the privilege to have looked through the lens she had used on the plants she lovingly studied.

Further information

http://www.utas.edu.au/library/exhibitions/winifred_curtis/

Eucalyptus viminalis (White Knight)

It is common knowledge that the Mountain Ash (Eucalyptus regnans) is the worlds tallest flowering tree and that Tasmania has some of Australia’s tallest old growth forests. So magnificent are the Mountain Ashes that significant individuals  have earned appellations such as ‘Centurion’ and ‘Methuselah’. Alas, the legend of the Mountain Ashes have overshadowed the other giants that reside in Tasmania. There are other giants among the eucalypts that are worthy of more general recognition, and it may come as a surprise to some that the White Gum (Eucalyptus viminalis) is one of them.

Practically every plant enthusiast in Tasmania and many tourists who visit the state has seen the grand Mountain Ashes of the Styx or the Tarkine. Few however, even among Tasmanian botanists, have met or are even aware of the giant White Gums of Tasmania’s Northeast. This is because White Gums are often thought of as average sized trees  associated with dry forest. Yet, in the Evercreech Forest Reserve just 10km from Fingal, a forest of giantic white gums, locally called White Knights, preside over the wet forests. For centuries they have watched, like silent sentinels from their statuesque vantage point, the changing landscape of Tasmania’s Northeast. The time is nigh for the White Knights to take their rightful place in the annals of Tasmania’s rich botanical heritage, for nowhere else in the world does one encounter white colossuses such as these.

Another magnificent White Gum in stark contrast to the verdant wet forest understorey

In the 1970s a forester named Des Howe was carrying out a routine survey in the forest about to be fell when he noticed that one of the trees that was to be felled was very tall. A surveyor came in and measured the tree to be an incredible 91m. A more accurate measurement of 89m was later given in the gianttrees website. Girth-wise, the White Knight is just as impressive, being 3.3m in diameter. The White Knight is also believed to be over 300 years old. Due to the presence of the White Knight, 52 hectares in the area was made a forest reserve to preserve the White Knight and other giant White Gums that reside there.

The story goes that botanists initially did not believe that the tall tree reported by the Forestry Commission was a White Gum until leaf and fruit specimens were brought before them. Likewise for me, my experience of the white gum being a average size tree of dry forest was so ingrained that I would have scarcely believed that the White Knights were White Gums until I saw the characteristic seed capsules myself.

It is not difficult to see how the first foresters who came before the presence of the giant white gums likened the trees to Knights, perhaps spotting shiny-clad armour. White has always been the colour of purity and goodness, and there is nothing quite like the sight of Brobdingnagian white boles standing in blazing contrast to a deep green forest understorey. And I am properly awed and impressed, just as the visitors before me that have come to pay their obeisance to the White Knights.

The elephantine girth of the White Knight

Had humans not implemented a system of recording in the form of herbaria or writing, we might never know what wondrous plants grew on the soils of Northwest Tasmania almost two centuries ago. It was 174 years ago in the winter of July 1836, when the imminent naturalist Ronald Gunn found a little species of Wurmbea, or what is known by Australian naturalists as Early Nancys, probably alluding to the early spring or winter flowering habit of members of the genus.

Wurmbea is a genus belonging to the botanical family Colchicaceae, a split-off family from what was once the great family of the Lilies. The Colchicaceae  includes other Australian lily-like plants like Milkmaids (Burchardia sp.), or more famously the Autumn Crocus (Colchicum autumnale) of the Northern Hemisphere and the Glory Lily (Gloriosa superba) of the tropics. The species Ronald Gunn discovered was named Wurmbea latifolia, or the Broad leaved Early Nancy, and is also found in New South Wales, Victoria and South Australia. Tasmania has another three species of Wurmbea, including the very common W. dioca which graces our heathlands every winter-spring. W. latifolia, however has not been observed since Ronald Gunn’s collection.

Wurmbea latifolia at Cape Grim 2010. Photo credit: Richard Schahinger

Could it be that some plants are just masters at being cryptic, to provide that ineffable purpose that drives many a botanist and plant hunter. Amazingly, Wurmbea latifolia was ‘re-discovered’ after almost two centuries in July this year by ecological planning advisor Richard Barnes from Cape Grim near Woolnorth, Northwest Tasmania and was in the news on the Mercury this monday (see news article).

At least a few hundred plants were found within a small one hectare area, in pretty much the same locality where Ronald Gunn had collected the plants. This significant rediscovery in Tasmania is by botanical standards comparable to finding the Gospel of Judas! The plants Richard Barnes found are likely the direct descendants of those found by Gunn, providing a direct link to the botanist extraordinaire of the past. Such a discovery augments the place of botany in Tasmania’s history and brings renewed faith that even on an island as small as Tasmania, there is still much to rediscover.

Portrait of Leonard Rodway (1853-1936)

A foray into the history of Tasmanian botany brought me to a website featuring what is perhaps the very first botanical-naturalist publication of Tasmania, a century old book titled Some Wildflowers of Tasmania (1910) by Leonard Rodway.

I had learned in my undergraduate years that Leonard Rodway was the head of the first herbarium, but this piece of information was anecdotal at best. There was much more to the man than just the ‘head of the herbarium’.

Leonard Rodway was born in 1853 in England to a dentist Henry Baron Rodway and his wife Elizabeth. He first trained to be a midshipman but eventually followed his father into dentistry. He migrated to Queensland and later Tasmania and was subsequently registered under the first Tasmanian dental act in 1884.

Dentist by trade, Rodway pursued plants during his weekends and holidays and in 1896 became the honorary government botanist.

A self-made authority on Tasmanian plants, Rodway published prolifically in the Royal Society of Tasmania. His magnum opus The Tasmania flora was published in 1903, and became the standard reference on the topic for 40 years until the era of Winifred Curtis began (which shall be covered in another post). Rodway also published a series of monographs, the Tasmanian Bryophyta, between (1912-1916) which, although outdated, still stands as the most complete work on Tasmanian bryophytes by a single author.

Ozothamnus rodwayi (Alpine Everlastingbush), an alpine daisy that bears Rodway's name

Rodway retired from public life in 1932 and passed away in 1936, aged 83.

In a time when the study, teaching and application of botany depended on the initiative of individuals and voluntary organizations, Leonard Rodway single-handedly raised and sustained the ford of Tasmanian botany. In that respect, it would not be too inaccurate to title him “the founder of Tasmanian botany”.

Rodway’s botanical achievements have been described as ‘a true gift to the people of Tasmania’. Several plant and fungal species bear the specific epithet rodwayi in his honour (examples are Eucalyptus rodwayi, Gahnia rodwayi, Entoloma rodwayi) and a number physical features in the Tasmanian highlands (eg. Rodway’s Pass in Mt Field National Park) perpetuate his memory. For the student of botany though, Rodway’s name will always be remembered through verbal transmission, when instructors of field botany pronounce the names of plants which immortalize Rodway.

When ardent students of mosses or bryologists traverse the globe to come to Tasmania, they will have, among the top candidates of their ‘to-see’ list, an `endemic Tasmanian moss. This is none other than Pleurophascum grandiglobum.

Rest assured that this moss lives up to it’s grandiose name. As this moss is so distinctive and significant, I’ll take the liberty to call it the Globe Moss, a name that I will use henceforth.

The moss was first described by Sextus Otto Lindberg in 1875, an early bryologist, in the Journal of Botany. He wrote (annotations in parentheses mine):

‘I Have to-day received from my friend Baron F. von Mueller, the renowned Director of the Botanic Gardens of Melbourne, a small tuft of a Moss, gathered this year by Mr. Robert Johnston on turfy soil near Picton River, in Tasmania. This Moss is of the highest importance, indeed of no less interest to the Muscologist (moss specialist) than is Rafflesia or Welwitschia to the Phanerogamist (higher plant specialist). It is, in fact, a very robust Phascaceous (bud-like) plant with the fruit perfectly lateral on the stem! I dare not as yet call it truly pleurocarpous (fruiting from specialized side branches), as its affinity is most obscure; but as it has, as far as I know, not been described, it ought to be called Pleurophascum grandiglobum…’

The Globe moss appears to be largely restricted to Buttongrass sedgeland habitats in the western part of the state. In a sterile state, the leaves are beautifully and symmetrically arranged around the stem and from the top look like the way lotus petals are arranged around their flower axis. The leaves are almost cup-like, lack nerves, but usually, although not always, have a single hairpoint at the apex. These characters, with the additional habitatual context, renders the Globe moss difficult to mistake for anything else.

When this moss is in fruit however, it is most unmistakable! The green spherical capsules, which ripen a dull yellow-brown, are 3-6mm in diameter, and are possibly among the largest, if not definitely the grandest, of all mosses in Tasmania. These grand structures that gives the moss it’s specific epithet ‘grandiglobum‘ are borne proudly on long setas (or stalks).

The capsules are cleistocarpous, a sophisticated way of saying that it does not open regularly through a well defined mouth, but rather, splits open irregularly at maturity. Precious little is known about the dispersal mechanism of the spores, much less on why the moss appears to be restricted to Buttongrass sedgeland habitats.

There are other reasons as to why the Globe moss is of such botanical interest. The distribution of the members of Pleurophascum are highly disjunct. One species P. ocidentale occurs in Western Australia. Another species, P. ovalifolium, occurs in New Zealand and was only recently determined by Australasian bryologists Alan Fife and Paddy Dalton in 2005 to be a different species from P. grandiglobum.

The affinities of Pleurophascum to other mosses are unclear. Bryologists have variously proposed that it is related to the Bryum (the Bryaceae) or Pottia (the Pottiaceae) mosses, but until more convincing evidence surfaces, it is best that the Globe moss remain in a family of it’s own, the Pleurophascaceae.

If there should one day be an international exhibition of mosses, where every country were to submit a portraiture of a unique indigenous moss for exhibition, there can be little doubt that the Globe moss will be the prime candidate to represent Tasmania’s bryological heritage. As far as mosses go, the Globe moss puts Tasmania on the world map.

The Blue Gum (Eucalyptus globulus), Tasmanian Waratah (Telopea truncata), Deciduous Beech (Nothofagus gunnii), Myrtle Beech (Nothofagus cunninghamii) and Pandani (Richea pandanifolia) are names that are often cited by plant enthusiasts and bushwalkers guidebooks as ‘must-sees’ of Tasmania.

But these five iconic plants, showy and famous as they are, must defer to THE ONE TRUE ICON plant that represents Tasmania — the Delicate Laurel (Tetracarpaea tasmannica). The popular portraiture of Tasmania’s botanical gems must be expanded to exalt the Delicate Laurel and to remedy it’s unfortunate oversight.

(Yes I am being evangelical).

The Delicate Laurel is by no means an uncommon plant. It occurs in wet forest or more often, subalpine shrubberies in the western mountains. The plant blends quite immaculately into the surrounding scrub and is not extremely prominent unless in flower, the erect flower stalks bearing small odd-looking white flowers with 4-5 oversized carpels (female parts). Without consciously looking for it however, Tetracarpaea would be quite easy to overlook whilst hiking pass the lush shrubbery vegetation. Once known however, the plant is easily recognizable by it’s thick leathery serrated leaves. The brown dry fruits (folicles) are also quite distinctive.

Distinctive as it is, the history of how the plant was named and classified has been fraught with difficulty and confusion (See Tasmanian Flora online profile).

The eminent botanist Joseph Dalton Hooker is often attributed with having named and described the plant in but it has only recently been clarified that it was his father, Sir William Jackson Hooker that had found and described the plant (The original illustration of the plant in Sir William Hooker’s Icones Platarum may be found here). It was also only recently that the correct species epithet ‘tasmannica‘ was reinstated, as opposed to the commonly but mistakenly used ‘tasmanica‘.

Botanists also have had difficulty determining the affinities of this enigmatic little shrub. They variously thought it to be related to the Horizontal bush (Anodopetalum biglandulosum), the Native Laurel (Anopterus glandulosus), and even Saxifrages. Only recently have molecular methods demonstrated that the closest relatives of Tetracarpaea are actually raspworts (Gonocarpus spp. and Haloragis spp.) and watermilfoils (Myriophyllum spp.). Still, the unique traits of the Delicate Laurel dictate that it is best placed in a family of it’s own, the Tetracarpaeaceae.

So there we have it. A true botanical orphan found ONLY in Tasmania.

The ONLY species in the genus.

The ONLY genus in the plant family Tetracarpaeaceae.

A prime example of Tasmania’s botanical heritage.

Forget about beeches, waratahs, pandanis and blue gums for a moment. These long revered icons have been discussed, photographed, drawn and stylized in Australian art ad nauseum. A true connoisseur of plants visiting Tasmania for the first time must embark on a montane pilgrimage and pursue first and foremost the one and only Tetracarpaea.

Tasdendro goes live!

The study of tree rings or dendrochronology is the scientific method of dating the age of trees based on the patterns of tree rings.

The topic of tree rings is close to my heart, particularly given that it is a major part of my current job scope (I work for the Forest Ecology lab in the School of Plant Science and I study the tree rings of an Australian cypress pine Callitris columellaris).

I am hence very pleased to announce the launching of tasdendro.org, a website with the intention of collating all the known information of Tasmanian dendrochronology. The web site was set up under the auspices of the Forest Ecology lab. In particular, Clay Trauernicht, a postgraduate student of the lab, has played a key role in the setup of the website.

The website is coupled with a newly set up storage facility with the purpose of being a repository for tree core material collected from Tasmania.

Given the current interest in climate change and the topic of carbon storage (see my earlier post on Sam Wood’s study), the setting up of such a facility and the Tasdendro website couldn’t have come at a more opportune time!

To the untrained eye it is possible to mistake certain flowering plants as mosses. Tasmania has a few examples, particularly some of the alpine bristleworts, which are small and turfed and even produce flowering stalks that superficially resemble moss capsules.

Much less likely is it for mosses to be mistaken as flowering plants, but yet, this was exactly what happened to a certain Australian moss by the name of Gigaspermum repens.

G. repens is a moss I had always wanted to see but Tasmania was not the best of places to be looking for it as it more typical of bare dry soils. This spring I was most fortunate to stumble on a small population near a rock outcrop on the summit of Mt Nelson.

The pale silvery quartz colour of the shoots were scarcely half a centimeter tall and reminded me of the ubiquitous Silver Moss (Bryum argenteum). Fortuitously, the plants I found were fertile, and in that state, there was absolutely no mistaking them. The fertile shoots were more than twice the size of the sterile ones and were, for lack of a better word, so pregnant.

Unlike most mosses which have capsules borne on a stalk held above the plant body, the capsules of G. repens were nestled among large modified leaves.

In this fertile state, plants are not dissimilar to minute flowers in bud. The capsule of Gigaspermum repens has a large operculum which falls off when the capsules are ripe, leaving a great gaping mouth and exposing the characteristically large spores (hence ‘Gigaspermum‘ which means large seeds) that are just visible to the naked eye.

These large spores could be mistaken for seeds in a pyxidate capsule, a type of fruit in flowering plants like plantain (Plantago spp.) where the top falls off to release the seeds. The uniqueness of Gigaspermum has inspired bryologists erect a botanical family, the Gigaspermaceae, to accommodate it.

When the great 19th century plant collector Ferdinand von Mueller (1825-1896) found this plant, he allegedly thought it was a flowering plant belonging to the ice plant family (Aizoaceae) and named it Trianthema humillima.

Mueller was a first rate botanical collector and his mis-description is no reflection of the lack of expertise on his part. Mueller was certainly aware of what mosses are. However, this episode does bear testimony to the morphological diversity that mosses can encompass, sans flowers.

I finally managed to take the time out to pop down to the Morris Miller Library, UTAS, to have a good look at the Moss Mania exhibition. Unfortunately I had missed the launch of the exhibition due to sickness.

The exhibition was situated in the exhibition cases at the entrance of the Morris Miller library, with Dr Rod Seppelt’s work was featured in a row on top, and those of Lauren Black were at the bottom. Immediately apparent was the contrast in artistic styles of the two masters.

Rod’s work was done in Indian ink on polyester film, producing a bolder effect. It also included technical histological illustrations of leaf and stem sections. Lauren’s work were pencil drawings and had a more aesthetic feel, with a focus more on capsule details. Nevertheless, it is without a doubt that both are first rate artists and have achieved mastery of their craft.

In addition to displaying the botanical artwork of Dr Rod Seppelt and Lauren Black, the Moss Mania exhibition also featured an impressive number of old books and short biographies of botanists and botanical artists involved in the early years of bryology (the study of bryophytes).

An example of one priceless volume was a book published in 1798, the Theoria generationis et frutifications plantarum cryptogamicarum Lannaei: retractata et aucta by Johann Hedwig. Book titles were rather verbose at that time, it would appear.

While it might seem alien in our current times where virtually everyone spots a camera, some of the early books on bryology actually had real specimens pressed between it’s pages. I had only ever read of something like that until I saw it with my own eyes in the exhibition.

The only other logical means for those early bryologist to depict the subjects of their study would have been via illustrations, and this art it seems, was elevated to a rather sublime level by the 19th century. They even had a system of colour codes so as to accurately depict the colours of the plants they were illustrating.

Modest as the exhibition was, it is impossible to leave without an appreciation of the intricacies required in the craft of botanical artistry, and the rich historical context that has culminated in the sublime artwork of the women and men who continue this admirable art-science synthesis.

The Moss mania exhibition continues till the end of November.

Artist profiles:

Lauren Black studied at the Royal Botanic Gardens, Melbourne and has been producing botanical masterpieces since 1997. Lauren has won numerous awards for her artwork and continues her work as a freelance solo artist and teacher A more detailed profile may be found on her professional website.

Rod Seppelt joined the Australian Antarctic Division in 1978 and is a adjunct professor at the Institute of Arctic Biology, University of Alaska, USA. He has published a book, The Moss Flora of Macquarie Island, and continues to work on drawings for projects like the Flora of Australia. His profile may be seen at the Australian Antarctic Division’s webpage.