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So Dryandra Becomes Banksia - What's All the Fuss About?

Tony Cavanagh

The following article, which was originally published in the newsletter of the Dryandra Study Group, raises a number of issues of wider interest to those interested in Australian native plants. There was a time when plant classification could be understood by anyone willing to spend a bit of time with a magnifying glass and a botanical dictionary. It seems that those days are past. Modern taxonomy is just about impenetrable to the lay person and the Banksia/Dryandra reclassification is just one example. There are likely to be many others.

In February this year, Austin Mast and Kevin Thiele published a foreshadowed paper entitled "The transfer of Dryandra R.Br. to Banksia L.f. (Proteaceae)". Austin Mast is an American botanist/biologist based in Florida USA and Kevin Thiele was recently appointed as the Head of the Western Australian Herbarium. What they both have in common is a strong interest in what I might call the "new systematics" or the use of complex DNA analyses and cladistics to try to classify plants. Both have published several papers in this area relating to Banksia (indeed both their PhDs examined this genus) while Mast has extended his interest to the Banksia/Dryandra relationship and has found what he believes is compelling evidence that not only are they closely related but that his data shows that "Dryandra [is placed] among the descendents of the most recent common ancestor of the more widespread Australian genus Banksia" (Mast and Thiele, 2007)*. In other words, Dryandra is not a separate genus but forms one group at the rank of series within Banksia. Alex George discusses this in an article in the Dryandra Study Group newsletter (July 2007) and I have to agree that, given how diverse we know Dryandra species to be, it is indeed extraordinary that the Mast analysis concludes that all the dryandras are closer together (ie more similar to each other) than some Banksia species are to each other.

I used the term "cladistics" above and include a definition from the Internet site "The free dictionary by Farlex" to try to explain it. It also includes a shortened definition of "taxonomy":

cladistics or phylogenetic systematics, an approach to the classification of living things in which organisms are defined and grouped by the possession of one or more shared characteristics (called characters) that are derived from a common ancestor and that were not present in any ancestral group (as envisioned by Charles Darwin's idea of "descent with modification"). Developed by Willi Hennig, a German entomologist, in the 1950s, it is a method of reconstructing evolutionary relationships that emphasizes the importance of descent and common ancestry rather than chronology.
taxonomy, the study of the relationships of organisms, which includes collection, preservation, and study of specimens, and analysis of data provided by various groups of biological--.

It doesn't help a lot and herein lies one of the greatest difficulties of the new systematics - it involves techniques, procedures and practices which are largely inaccessible to and not easily understandable by the average person. Traditional descriptive morphological analysis at least had the advantage that almost any person could read and understand it, although these new techniques may well show that there are deficiencies with the old practices (eg. as I understand it, Callistemon no longer exists and has now been included as a group within Melaleuca). I do not know if this will stand scrutiny in the future and it could be argued that the same thing is now happening with Dryandra and Banksia. Time will tell. I just want to summarise the overall effect of the new proposals on Banksia and Dryandra as we now know them and perhaps speculate a little on a brave new world of Australian plants if other conceivable "combinations" of genera occur.

What changes are proposed

Dryandra quercifolia
  Dryandra quercifolia (Banksia helianthi?)
Photo: Margaret Pieroni

Dryandra longifolia
  Dryandra longifolia (Banksia prolata?)
Photo: Margaret Pieroni

Mast and Thiele claim they have followed the least disruptive path in adopting new names and combinations. The need for changes arises of course because, for example, the same species name occurs in both "old" Banksia and "old" Dryandra (eg. baxteri, brownii, pulchella etc, 18 in total). They have attempted to use new descriptive names which relate to the original diagnostic feature on which the former name was based. Thus the "old" Dryandra pulchella becomes Banksia bella, the "old" D. glauca becomes B. glaucifolia and "old" D. longifolia becomes B. prolata (from the Latin prolatus, "extended, elongate", a reference to the long, narrow leaves). The changes for proper nouns (people's names such as Brown and Baxter) are much more convoluted and I won't bore you with the details. However, some of the names proposed are seemingly fairly inappropriate (eg. Banksia helianthi for the "old" D. quercifolia where the new name supposedly is derived from the Greek helios (sun) and anthos (a flower). Do you think that D. quercifolia looks like a sunflower? Likewise, D. speciosa become B. splendida (from the Latin splendidus (shining, brilliant). This is hardly appropriate for flower heads which are pendant and surrounded by dull grey bracts, although of course the original epithet "speciosa" (showy) is not particularly accurate either.

The rest of the name changes are what are called "new combinations" and are used when the "old" Dryandra name is discrete. Thus D. arborea becomes B. arborea, D. carlinoides becomes B. carlinoides, D. ferruginea becomes B. ferruginea and so forth for around 108 taxa. The Mast-Thiele paper does not include the six new taxa published in Alex George's paper in December 2005, so these names remain "legitimately" (at least for the moment) as Dryandra.

Speculations on some effects of such changes

Some of the problems which face users (gardeners, Australian plants people, nurserymen and horticulturalists) with such wholesale name changes include confusion, frustration with yet more name changes to the extent that most people will say, "I don't care what they call it, to me it's Dryandra x", and concern as to whether these name changes will ever stop. It does nothing for popularising Australian plants and certainly absolutely nothing if we are trying to persuade people to use species names instead of common names and recognise them in gardens. To make matters worse, the botanists who are proposing these changes seemingly do little to try to explain to lay people why their work is important and why changes are necessary. Why are DNA work and molecular studies so important and why are they seemingly the final arbiters when taxonomic decisions are being taken?

Dryandra ferruginea
  Dryandra ferruginea (Banksia ferruginea?)
Photo: Margaret Pieroni

At the next stage, the nursery and horticultural trade and in Herbaria throughout Australia, the problems are immensely compounded. Old labels will have to be scrapped and a whole lot on new ones produced, names on stock plants will have to be changed and a whole new education program for the public will be needed (eg. that all those plants you knew as "bottlebrushes" are actually Melaleucas. In Herbaria, it will be a mammoth and costly task to correct Herbarium sheets. With the proposed Dryandra into Banksia merge, it may not be too much as there are probably only three Herbaria with substantial Dryandra collections. But if Grevillea is absorbed into Hakea, and Isopogon and Petrophile are merged, the task will be colossal as all these genera occur in most states. Does anyone really want this and does it really advance our knowledge of Australian plants?

I would be delighted to be shown to be wrong but at the moment it appears that much of this molecular work is "science for science's sake" with little concern for practical considerations. Sure, we want things to be "right" but how far do we go in pushing the technology? I guess that my challenge to the "new" taxonomists is to EXPLAIN to us in layman's terms just what they are doing, why they are doing it and why molecular systematics is seemingly the only answer. Is there any place for the "old" techniques and if so, do they have any chance against this onslaught? I think that they also owe it to us to foreshadow other possible changes (eg. Verticordia/Chameleucium/Homoranthus and perhaps even more combinations within Melaleuca and its (current) allied genera. And lastly I think that it is high time that there was a lot more dialogue between the taxonomists and other professionals in the horticultural, nursery and Australian plants businesses. Wanting to find the truth is one thing, but "science for science's sake" and hang the practical consequences, is something else again.

* Mast, A.R. & Thiele, K. (2007), The transfer of Dryandra R.Br. to Banksia L.f. (Proteaceae), Australian Systematic Botany 20: 63-71.

From the July 2007 issue of the newsletter of ASGAP's Dryandra Study Group.

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