Big trees of small baskets: phylogeny of the Australian genus Spyridium (Rhamnaceae: Pomaderreae), focusing on biogeographic patterns and species circumscriptions
Author
Clowes, Catherine
Author
Fowler, Rachael M.
Author
Fahey, Patrick S.
Author
Kellermann, Jürgen
Author
Brown, Gillian K.
Author
Bayly, Michael J.
text
Australian Systematic Botany
2022
2022-05-18
35
2
95
119
http://dx.doi.org/10.1071/sb21034
journal article
293192
10.1071/SB21034
3342e1b6-1f21-44a4-a117-a2b6d07545f1
1446-5701
10949882
Spyridium eriocephalum
Spyridium eriocephalum
is polyphyletic and requires taxonomic revision, because its two varieties were found in distinct clades in both nrDNA and cpDNA phylogenies (Clades
F
and
I
,
Fig. 2
; Clades
M
1 and
Q
2,
Fig. 5
).
Spyridium eriocephalum
var.
eriocephalum
is monophyletic (albeit with limited sampling, but from separated localities) and geographically distinct from other taxa in the nrDNA tree (
Fig. 2
,
3
f
).
Spyridium eriocephalum
var.
glabrisepalum
is unresolved in a polytomy in the nrDNA phylogeny (Clade
I
,
Fig. 3
) with several other taxa (
Fig. 2
,
3
i
). The two varieties of
S. eriocephalum
are for the most part geographically distinct, with the exception being some overlap on Kangaroo Island (
J
. Kellermann, unpubl. data). The typical variety is widespread in south-eastern
Australia
(
SA
,
Victoria
,
NSW
and
Tasmania
), whereas
var.
glabrisepalum
is restricted to Kangaroo Island. The two varieties are also morphologically distinguished by the presence of woolly sepal hairs (
var.
eriocephalum
) versus hairless sepals that are instead glabrous-viscid (
var.
glabrisepalum
;
Canning 1986
). Although the two taxa appear distinct (from each other) in both phylogenies, given that the two samples of
var.
glabrisepalum
are placed with some other Kangaroo Island endemic taxa (e.g.
S. coalitum
) in the nrDNA tree, it is possible that introgression may be influencing this placement (
Fig. 2
). However, placement of
var.
glabrisepalum
in the cpDNA phylogeny is somewhat incongruent although supported, with samples being placed with accessions representing other taxa collected from a range of sites from
SA
to
Tasmania
(
Fig. 5
). Additional morphological or molecular work is recommended to re-assess these taxa and their relationships.