From: "Wilbert Hetterscheid" <hetter at xs4all.nl> on 2011.01.21 at 16:56:00(21786)
Peoples, more particularly Typhoniophiles,
There is a lot going on in the systematics (taxonomy) of Typhonium. It is
time I gave you a rundown of what has happened the last year when two
significant but very contrary papers have appeared on Typhonium. As a very
short first warning: Typhonium s.l. (sensu lato = in the wider sense) has
been split up in 3 genera, Typhonium s.str. (sesu stricto = in the strict
sense), Sauromatum (there it is again, resurrected) and "The Aussies".
Matthew Barrett (mentioned on the website with the discussed Typhonium
picture from Kimberley) is presently revising the Australian group, which
turned out to be independent in evolutionary terms of Typhonium s.s.tr. and
Sauromatum. Therefore this Aussie group will get a new name and the first
name available for it is probably Lazarum, a genus published for L. mirabile
by Alistair Hay, several years ago.
What brought this about?
You may remember that Peter Boyce and myself (Aroideana 23, 2000) considered
on morphological grounds only, that Sauromatum and Typhonium were too much
alike to be kept separate. Not to say that there were no differences at all
but they seemed insignificant at the time (you see that I am trying to keep
guilt at a minimum here....... :-). The molecular revolution in plant
systematics has finally also reached Typhonium and in 2010 two papers on
this subject were published within a few weeks of each other. First came:
Cusimano, N., M.D. Barrett, W.L.A. Hetterscheid & S.S. Renner: A phylogeny
of the Areae (Araceae) implies that Typhonium, Sauromatum, and the
Australian species of Typhonium are distinct clades. TAXON 59 (2) . April
2010: 439-447.
A few weeks later:
Ohi-Toma, T., S. Wu, S.R. Yadav, H. Murata & J. Murata: Molecular Phylogeny
of Typhonium sensu lato and Its Allied Genera in the Tribe Areae of the
Subfamily Aroideae (Araceae) Based on Sequences of Six Chloroplast Regions.
Systematic Botany (2010), 35(2): pp. 244-251.
The basic conclusions of Cusimano et al. are that Sauromatum is not part of
Typhonium and has to contain 9 species we now know mostly as Typhonium or
Sauromatum (S. brevipes, S. brevipilosum, S. diversifolium, S.
gaoligongense, S. giganteum, S. hirsutum, S. horsfieldii, S. tentaculatum,
S. venosum). Another coclusion is that the endemic species of Australia are
not closely enough related to Sauromatum or the remaining Typhoniums, to be
part of either. So it will have to be a separate genus with its own
evolutionary status. Matthew is presently revising all Aussies and when it
is certain that Lazarum mirabile (renamed Typhonium mirabile by Peter and
myself in 2000) also belongs to this group then the names of all Aussie
Typhos will change to Lazarum. Let's wait for Matthew's work to be published
and see. That leaves all other former Typhonium species as "proper"
Typhonium.
The Japanese paper is based on much less material and no Australian ones at
all. The evolutionary diagram has a number of unresolved areas and
unfortunately, the authors still felt it necessary to divide Typhonium s.l.
in no less than 5 genera, of which three new ones, Diversiarum for T.
diversifolium, T. alpinum), Pedatyphonium for T. horsfieldii, T. larsenii,
T. kunmingense, T. calcicolum, T. omeiense (all these species in my own mind
are one T. [Sauromatum as per Cusimano et al.] horsfieldii, and Hirsutiarum
for T. hirsutum and T. brevipilosum (both Sauromatum acc. to Cusimano et
al.). In short, where Cusimano et al. have expanded Sauromatum on the basis
of a fully resolved evolutionary scheme, Ohi-Toma et al. found an unresolved
scheme and still decided to create new genera for several Sauromatum
species. A decision to create genera based on an unresolved evolutionary
scheme is, to say the least, ill-advised. Unresolved evolutionary
relationships await further analysis to create a more stable scheme and only
then is it useful to make taxonomic decisions leading to changing
nomenclature.
To boot, the new generic names by Ohi-Toma et al. are all invalidly
published because they made a crucial citation mistake with every one of
them.
The recently published English edition of the Flora of China follows the
Cusimano et al. taxonomy and will stand as an authoritative publication.
It is a pity that cooperation between the two groups which has been promoted
by the Cusimano gang, was not answered by the Japanese-Indian group, or this
situation could have been avoided.
Anyway, you Typhoniophiles will have to adapt to this new taxonomy. Then
again, good ol' Sauromatum venosum is back again!
Cheers,
Wilbert
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