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
Tzvelev,
Novosti Sist. Vyssh. Rast.
27: 151 (1990)
Type
:
Xerochrysum bracteatum
(Vent.) Tzvelev.
Bracteantha
Anderb. & Haegi,
Opera Bot
.
104: 102 (1991)
,
nom. illeg.
Type
:
Bracteantha bracteata
(Vent.) Anderb. & Haegi.
Annual
or
perennial herbs
, usually taprooted, sometimes rhizomatous.
Indumentum
cobwebby, felted, hirsute, hispid, pilose, tomentose, villous, or woolly, with septate trichomes, often flagelliform, and with sessile or stipitate glands.
Leaves
alternate; lamina flat or with margin recurved.
Capitula
terminating branches or branchlets, homogamous or heterogamous, disciform.
Phyllaries
multiseriate, medial phyllaries longest; lamina rigidly chartaceous, often spreading at junction with claw when mature; claw coriaceous, broadly oblong, flat; stereome broad, that of inner phyllaries fenestrate, veins numerous and extending into lamina, veins each of equal thickness in the
X. bracteatum
group, or central vein thickest in the
X. milliganii
group.
Receptacle
± flat or concave, epaleate.
Outermost florets
usually sterile or sometimes female;
corolla
very narrowly tubular, shorter than bisexual florets, 3-, 4- or 5-lobed.
Inner
(or all)
florets
bisexual;
corolla
narrowly tubular, 5-lobed, lobes ovate, yellow to orange; anthers with apical appendage ovate and outwardly concave, tails slender, ±equal to collar, pollen pale yellow; style arms slender, with rounded, clavate, ovate, deltoid, triangular or narrowly triangular stylar appendage, yellow.
Cypsela
cylindrical or oblong, ~
2.5–3.5 mm
long; pericarp thick, finely striated, glabrous, surface with linear idioblasts, brown or straw- or bronze-coloured; stipe hollow, carpopodium of one row of thickened cells; apex patelliform when mature.
Testa
free from pericarp, cells ±equilateral, without thickening; vein passing to apex.
Pappus
uniseriate; bristles slender, equal to or exceeding corolla, white or yellow, consistent with the colour of the medial phyllaries, barbellate with apical cells acute and occasionally coloured red, bristles very shortly united at base and eventually deciduous as a whole or in pieces in the
X. bracteatum
group, or persistent in the
X. milliganii
group.