Xerochrysum banksii (A.Cunn. ex DC.) T.L.Collins

Collins, Timothy L., Schmidt-Lebuhn, Alexander N., Andrew, Rose L., Telford, Ian R. H. & Bruhl, Jeremy J., 2022, There’s gold in them thar hills! Morphology and molecules delimit species in Xerochrysum (Asteraceae; Gnaphalieae) and reveal many new taxa, Australian Systematic Botany 35 (2), pp. 120-185 : 144-145

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.

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!).

Figures

Fig. 16. Distribution of Xerochrysum banksii.

Fig. 17. Lectotype of Xerochrysum banksii (G-DC G00328465). Image: © Conservatoire et Jardin botaniques de la Ville de Genève.