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 gudang
T.L.Collins & J.J.Bruhl
,
sp. nov.
Type
:
AUSTRALIA
:
Queensland
:
Cook
:
Somerset Lookout
,
Fly Point
, ~
350 m
SW of lookout parking area,
50 m
from rocky coast,
28 June 2018
,
T.L. Collins
1061 &
J.J. Bruhl
, (
holo
:
BRI
!;
iso
:
CANB
!,
CNS
!,
NE 107429
!)
.
[
Xerochrysum bracteatum
auct
.
non
(Vent.) Tzvelev: N.N. Tzvelev,
Novosti Sist. Vyssh. Rast.
27: 151 (1990),
p.p.
, populations in the Torres Strait and on the northern tip of Cape
York
Peninsula,
Queensland
only].
Diagnosis
Distinguished from
X. bracteatum
by a perennial life form (
v.
annual
or sometimes short-lived perennial), the presence of septate trichomes on leaf lamina abaxial surface (
v.
with
glands), and the absence of glands on stems and leaf lamina adaxial surface (
v.
with
glands). Distinguished from
X. strictum
,
X. banksii
and
X. boreale
by the absence of glands on stems and leaf adaxial surfaces (present on
X. strictum
,
X. banksii
and
X. boreale
).
Decumbent to erect, taprooted, perennial herb.
Stems
and
branches
up to
70 cm
long, cobwebby, hirsute, scabrid, or woolly, to glabrescent; internode length
10–20 mm
. Previous season’s flowering stems marcescent.
Basal leaf rosette
absent at flowering.
Basal leaves
oblanceolate to spathulate,
70–120 mm
long and
5–15 mm
wide, base subamplexicaul, margin villous with septate trichomes, apex mucronate; abaxial indumentum villous with septate trichomes, and with glands, midvein indumentum pilose with septate trichomes; adaxial indumentum villous with septate trichomes.
Cauline leaves
oblanceolate to lanceolate,
50–100 mm
long and
6–15 mm
wide, base auriculate and amplexicaul, margin cobwebby and hirsute with septate trichomes, apex mucronate;
abaxial
indumentum
hispid with septate trichomes and with glands, midvein indumentum cobwebby and hispid with septate trichomes;
adaxial indumentum
cobwebby and hirsute with septate trichomes.
Foliaceous bracts subtending capitula
6–8 mm
long, margin woolly to cobwebby, and hispid.
Capitula
30–40 mm
wide, terminal, in panicles.
Outer phyllaries
ovate to 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
deltoid.
Cypsela
oblong, ~
2.7 mm
long and
0.75 mm
wide, cross-section circular; pericarp straw- or brass-coloured, idioblasts present.
Pappus
deciduous, ~
8–9 mm
long.
Fig. 26. Isotype of
Xerochrysum frutescens
(I.R.Telford 12874, J.J.Bruhl & L.M.Copeland
NE 85983).
Distribution
Known only from the
Somerset
area of northern Cape
York
and nearby islands in the Cape
York
Peninsula Bioregion (
Fig. 27
). Extensive survey of similar habitat on Cape
York
Peninsula has not recorded populations of
Xerochrysum
between Jardine River National Park and Cooktown, except for
X. strictum
near Coen (J. R. Clarkson, pers. comm., 2018).
Phenology
Recorded in flower June–October and fruiting in June (
Fig. 28
).
Habitat
Windswept grassy herbfields among shrubland on low rocky headlands.
Conservation status
Population-size data are scant, with 50–100 plants being estimated at
Somerset
Lookout in 2018, and other specimen label data describing populations as ‘sporadic’ (
L.J. Brass 18778
), and ‘infrequent’ (
K.R. Thiele 905
). Given the very limited geographic range and estimated small population sizes, we suggest a ‘
Vulnerable
’ status is appropriate under the
IUCN (2019)
because it fulfils the criteria of D1 and D2. A precise assessment of population size and estimated stability would clarify whether
X. gudang
should be listed as ‘
Endangered
’ or ‘
Critically Endangered
’.
Notes
The decumbent habit observed in the field was retained on glasshouse-grown plants. The informal phrase name
X
. sp. Fly Point
NE
Herbarium has been used at
NE
for curatorial purposes and this study.
Etymology
The species epithet is the traditional name of the
type
locality, a place important to traditional owners (Christo Lifu, pers. comm., 2020), as a noun in apposition (Shenzhen Code art. 23.5;
Turland
et al
. 2018
).
Selected specimens examined
QUEENSLAND
:
Cook
:
Albany Island
,
s.dat
.,
W. Hill
71
(
K000899118
*);
Fly Point,
near Albany Pass
,
Cape York Peninsula
,
25 June 1973
,
S. Powell
9
(
CANB
!)
;
Fly Point
, ~
11 km
SE of Cape
York
,
30 Oct. 1965
,
L.S. Smith
12636
(
BRI
!)
;
Newcastle Bay
,
Cape
York Peninsula
,
15 Feb. 1986
,
D.L. Jones
s.n.
(
BRI
!)
;
Newcastle Bay
,
2.5 miles
S of Somerset
,
2 May 1948
,
L.J. Brass
18778
(
A
,
CANB
!)
;
Headland
above
Nanthau Beach
,
4.5 km
direct line SSW of Somerset
,
30 June 1985
,
K.R. Thiele
905
(
CANB
!)
.