Abstract
The revision of Metalasia by Karis (1989) made
it clear that the rest of the Metalasia group, as
defined by Anderberg (1991a), also needed to
be investigated. Anderberg (1991a) identified
the Relhania and Metalasia groups in the
subtribe Relhaniinae of the tribe Gnaphalieae.
The Metalasia group consists of 14 genera, of
which seven are monotypic and four have
recently been described. The monotypic
genera Bryomorphe, Dolicothrix and Phaenocoma
are well known, whereas the more recently
described Atrichantha, Calotesta, Hydroidea and
Planea (Hilliard & Burtt, 1981; Karis, 1990) are
known from limited collections. In the
broader context of the tribe it also became
evident that Disparago (Koekemoer, 1993),
Stoebe and Elytropappus (Levyns, 1937, 1935b)
needed to be re-assessed to establish the rank
of their formal and informal groupings. A
number of genera in the group: Amphiglossa,
Bryomorphe, Lachnospermum, Phaenocoma and
Pterothrix, had not been studied since Flora
Capensis (Harvey, 1865) and needed attention.
The aims of this study were therefore, to
clarify the taxonomy and nomenclature, to
provide full taxonomic treatments for all the
species in the Metalasia group, and to discuss
their phylogenetic relationships. The fact that
almost all taxa are endemic to southern Africa
provided additional motivation to investigate
the group. Furthermore the newly described
genera and species have not been studied in
the context of the whole group and the large
number of specimens that are available today
add a wealth of new information to the
available knowledge. The need for further
investigation was also emphasized by
comments by Anderberg (1991a) that
Elytropappus and Stoebe are probably
paraphyletic or polyphyletic and that
Amphiglossa is probably paraphyletic if
Pterothrix is kept separate.
Extensive fieldwork was undertaken to
investigate species in their natural habitat.
Spirit-preserved and dried specimens were
collected and studied in the herbarium.
Thorough morphological studies were
undertaken, with extensive use of the SEM
and light microscopes; photographs were
produced to document the characters.
Accurate records were kept of all specimens
to assist in determining distribution ranges for
each taxon as well as species densities for
every genus.
Anatomy of selected species was investigated.
The results revealed that the leaves of
Dolicothrix and Dicerothamnus were indeed
glandular, that there are two small resin
cavities in the leaf bases of some Seriphium
species, and for the first time, provided
information on leaf and cypsela anatomy for
the group.
During the course of this study several
nomenclatural problems were solved: the
correct name for Bryomorphe aretioides; Klenzea
lycopodioides is a synonym of Dolicothrix ericoides,
rather than of Bryomorphe; and the confusion
around the names Elytropappus gnaphaloides and
E. glandulosus was cleared. It was also found
that Elytropappus hispidus and E. cyathiformis,
and Stoebe cyathuloides and S. sphaerocephala are
conspecific. On generic level it was found
that Amphiglossa and Pterothrix are congeneric;
and that Disparago, Elytropappus and Stoebe are
paraphyletic. This resulted in Seriphium being
re-surrected for a group of Stoebe species, and
Disparago being divided into four genera and
Elytropappus into three. Taxonomic treatments
for 64 species, including nomenclature,
synonymy, typification, full descriptions,
geographical distribution, and keys to genera
and species, are given.
Fieldwork resulted in a large number of new
distribution records, the discovery of six new
species and also the re-collection of two
species (Amphiglossa callunoides and A.
corrudifolia) that were only known from type
specimens and were thought to be extinct.
Although attempts were made to investigate
the group, both chemically and cytologically, I
was not able to do this successfully. Chemical
results indicated that the volatile oils and
flavonoids are complex and would provide a
wealth of information for future studies.
Together with DNA investigations in the
Gnaphalieae it could possibly assist to unravel
existing uncertainties.
A summary of the taxonomic implications of this study is given below:
Genera New species No of
species
Taxonomic implications
Amphiglossa A. celans, A. grisea
A. rudolphii,
A. susannae
11 • Pterothrix as synonym with several new combinations
• Four new species
• P. flaccida and P. spinescens as synonyms
Atrichantha 1
Bryomorphe 1 • Nomenclature clarified
Calotesta 1
Dicerothamnus 2 • New genus
• New combinations
Disparago 4 • Reverting to original concept of Gaertner for the genus
• Three new genera created
Dolicothrix 1 • Klenzea lycopodioides as new synonym
Elytropappus E. aridus
E. monticola
3 • E. cyathiformis as synonym
• Genus split into three
Gongyloglossa 1 • New genus
• New combination
Hydroidea 1
Lachnospermum 3 • Nomenclature clarified
Laevicarpa 1 • New genus
• New combination
Metalasia 52
Monticapra 3 • New genus
• New combinations
Myrovernix 5 • New genus
• New combinations
• M. intricata transferred from Stoebe
Phaenocoma 1
Planea 1
Seriphium 9 • Resurrect the genus
• New combinations
• Elytropappus ruscianus, Stoebe burchellii and S. vulgaris as
synonyms
Stoebe 16 • S. copholepis, S. ensori, S. sphaerocephala, S. humilis, S. salteri
and S bruniades as synonyms.
Total 117
Characters and character states were evaluated
in terms of their taxonomic value and their
contributions towards an improved
understanding of phylogenetic relationships
amongst the genera and species of the
Metalasia group. The patterns of character
state distributions were explored, using
cladistic methods. This resulted in the
discovery of several ‘new’ characters, as well
as new ways of interpreting some of the ‘old’
characters. Examples include several very
interesting observations made by means of
SEM studies; e.g. the true identity of
Elytropappus cyathuloides, the glands on the leaf
surfaces of Dicerothamnus rhinocerotis, D.
adpressus and Dolicothrix ericoides as well as resin
cavities at the bases of leaves of some
Seriphium species. All data gathered from the
study were evaluated and analyzed cladistically
to determine inter- and infraspecific
relationships. New hypotheses regarding the
relationships amongst the genera and species
of the Metalasia group are presented.
Van Wyk, B.E., Prof.