There’s gold in them thar hills! Morphology and molecules delimit species in Xerochrysum (Asteraceae; Gnaphalieae) and reveal many new taxa
Author
Collins, Timothy L.
Author
Schmidt-Lebuhn, Alexander N.
Author
Andrew, Rose L.
Author
Telford, Ian R. H.
Author
Bruhl, Jeremy J.
text
Australian Systematic Botany
2022
2022-06-09
35
2
120
185
http://dx.doi.org/10.1071/sb21014
journal article
10.1071/SB21014
1446-5701
10903939
Xerochrysum banksii
(A.Cunn. ex DC.) T.L.Collins
& I.Telford,
comb. nov.
Helichrysum banksii
A.Cunn. ex DC.,
Prodr
.
6: 188 (1838);
Gnaphalium banksii
(A.Cunn. ex DC.) Sch.Bip.,
Bot. Zeit.
3: 171 (1845)
.
Type
citation
: ‘in Novae-Holl. ora boreali-orient. ad flum. Endeavour in sylvaticus graminosis olim legit cl. Banks et postea A Cunningham jul. flor (v.s. comm. a cl. A. Cunn.)’.
Type
:
Grassy
forest-land,
Endeavour River
, N.E.
Australia
[
Queensland
], lat. 15° south,
July 1819
,
A. Cunningham
s.n.
(lecto, here designated: G-DC G00328465*; isolecto: K 000899119*)
.
[
Helichrysum bracteatum auct
. non
(Vent.) Willd.: G.Bentham,
Fl.
Austral. 3: 620 (1867)
,
p.p
.]
[
Xerochrysum bracteatum auct
. non
(
Vent.) Tzvelev:
N.N. Tzvelev
,
Novosti Sist. Vyssh. Rast.
27: 151 (1990),
p.p
., populations on coastal headlands between
Cooktown
and Cairns,
Queensland
only]
.
Prostrate, tap-rooted, perennial herb.
Stems
and
branches
hirsute, scabrid, glabrescent and with glands; internode length
5–60 mm
. Flowering stems branched or unbranched.
Basal leaf rosette
present at flowering in first year, later absent.
Basal leaves
oblanceolate to spathulate,
50–120 mm
long and
10–25 mm
wide, base amplexicaul, apex mucronate, margin hirsute; basal leaf abaxial indumentum with glands and occasionally hirsute with septate trichomes, midvein indumentum pilose with septate trichomes; basal leaf adaxial indumentum hirsute with septate trichomes.
Cauline leaves
oblanceolate,
20–50 mm
long and
5–10 mm
wide, base subauriculate and amplexicaul, apex mucronate, margin hirsute;
abaxial indumentum
with glands, midvein indumentum hirsute with septate trichomes;
adaxial indumentum
hirsute, scabrid and with glands.
Foliaceous bracts subtending capitula
6–12 mm
long, margin hispid.
Capitula
30–40 mm
wide, terminal, solitary.
Outer phyllaries
broad-ovate, brown or straw-coloured, basal margin fimbriate and hispid, abaxial surface smooth, apex apiculate.
Medial phyllaries
narrow ovate to lanceolate, abaxially yellow, apex cuspidate.
Stylar appendages
triangular.
Cypsela
oblong, ~
2.5 mm
long and
0.9 mm
wide, cross-section squarish or circular; pericarp straw- or brass-coloured, idioblasts present.
Pappus
deciduous, ~
6 mm
long.
Fig. 16. Distribution of
Xerochrysum banksii
.
Distribution
Endemic to
Queensland
where it occurs in the Wet Tropics Bioregion on the eastern coast between
Cairns
and Cooktown (
Fig. 16
)
.
Phenology
Inflorescences recorded from June–December. Mature cypselae collected in July and October (
Fig. 17
).
Habitat
The species inhabits grassy herblands on rocky coastal headlands. Associated species include
Heteropogon triticeus
,
Themeda triandra
,
Myoporum boninense
and
Santalum lanceolatum
.
Conservation status
Only two collections are known from the past 15 years from a single population of unknown size in Annan River (Yuku Baja-Muliku) National Park. Populations recorded in the 1800s in Cooktown and Trinity Bay near Cairns may now be extinct because of intense coastal development. On the basis of only one known extant population of unknown size, we suggest that a ‘
Data Deficient
’ status is appropriate under the
IUCN (2019)
. Confirmation of the loss of populations in Cairns, Mossman River and Cooktown may qualify
X. banksii
as ‘
Endangered
’ or ‘
Critically Endangered
’.
Notes
Some variation in leaf indumentum was seen on specimens collected in the 1800s from Trinity Bay (
MEL
61211, and
MEL
61314), with a hispid to hirsute leaf indumentum both abaxially and adaxially with septate trichomes. Recent collections from Annan River National Park have no septate trichomes abaxially, only sessile glands. A specimen from Mossman’s [=Mossman] River (
W.A. Sayer s.n.
MEL
61192) has hispid leaf indumentum with much shorter septate trichomes.
Xerochrysum banksii
retains a prostrate habit in cultivation. The informal phrase name
X
. sp. Walker Point
NE
Herbarium has been used at
NE
for curatorial purposes and this study.
Alan Cunningham’s specimen at G-DC is here selected as the
lectotype
, as this specimen would have been used by de Candolle in preparing the protologue.
Selected specimens examined
QUEENSLAND
:
Cook
:
Endeavour River
,
June 1770
,
J. Banks
&
D. Solander
s.n.
(
MEL 1591810
!)
;
Cooktown
, 1877,
W. Persieh
s.n.
(
MEL 0061318
A!);
Endeavour River
, 1882,
W. Persieh
s.n.
(
MEL 0061336
A!);
Annan River National Park
,
Walker Point
,
22 Oct. 2018
,
A.J. Saunders
1
(
BRI
!,
CANB
!, CNS!,
NE 110024
!);
Walker Point,
S of Cooktown
,
5 Dec. 2005
,
B.S. Wannan
4156
(
BRI
!,
BSW
,
NSW
!)
; Mossman’s [=Mossman] River, 1886,
W.A. Sayer s.n.
(
MEL
0061192A!); Trinity Bay, 1881,
G. Karsten s.n.
(
MEL
0061211A!); Trinity Bay,
E. Fitzalan s.n.
(
MEL
0061314A!).