Ozothamnus filifolius Puttock, 2018

Schmidt-Lebuhn, Alexander N., Puttock, Christopher F., Davis, Robert W. & Wege, Juliet, 2018, Two new species of Ozothamnus (Asteraceae: Gnaphalieae) from Australia, Phytotaxa 336 (2), pp. 190-196 : 191-193

Ozothamnus filifolius Puttock , sp. nov. ( Figure 1 )

Ozothamnus sp. Filifolius (A.S.George 8292) WA Herbarium, Parker & Biggs (2014).

Ozothamnus sp. Petermann Ranges (J.R.Maconochie 778) NT Herbarium, Australian Plant Census, https://biodiversity.org.au/nsl/ services/apc (accessed 8 July 2017).

Type:— AUSTRALIA. Northern Territory: Fosters Cliff, 44 km SSW of Mt. Olga, 7 September 2009, D. E. Albrecht & P. K. Latz 13132 (Holotype NT D0194165 !; isotypes AD 240058 !, CANB 726648 !) .

Diagnosis:— Ozothamnus filifolius is similar to O. kempei (F.Muell.) Anderb. with which it shares white-woolly stems, linear leaves more than 5 mm long, leaf apices often with a reflexed mucro, strongly revolute leaf margins, adaxial leaf surfaces with short conical hairs and white-woolly abaxial leaf surfaces, but differs in having more slender leaves that are never more than ca. 0.7 mm wide (versus up to 1.2 mm) and smaller capitula 2.5–4.0 mm in length (versus 4.5–7.0 mm) and with only 8–13 flowers (versus 9–24).

Description:— Shrub to 2 m tall. Stems white-woolly and glandular. Leaves spreading to somewhat erect, almost sessile or with an indistinct petiole to 1 mm long, linear, 5–21 mm long, 0.4–0.7 mm wide, apex with a reflexed mucro, base not decurrent, margin entire and revolute to near the mid-rib, obscuring most of the abaxial leaf surface; adaxial leaf surface not channelled, with very short conical hairs, rarely glands; abaxial surface white-woolly. Capitulescence a corymbose panicle 10–40 mm in diameter. Capitula simple, conical to suborbicular, 2.5–4.0 mm long, 1.5–3.8 mm wide, sessile or on a peduncle to 2.2 mm long. Involucral bracts thin, mostly membraneous, spirally arranged, not radiating. Inner involucral bracts opaque white with yellowish to light brown stereome, oblanceolate, 2–3 mm long, 0.7–1.5 mm wide, the apex obtuse to rounded and generally entire, abaxial surface with glands and few woolly hairs. Receptacle bracts (paleae) absent. Flowers 8–13 per capitulum, white to cream. Pappus of c. 20 barbellate bristles or hairs 2–3 mm long, white to translucent, the tips clavate and/or slightly inflated. Immature cypsela brown, surface with minuscule ‘twin’ hairs.

Etymology:— Named for its very slender, linear leaves, after Latin filum, thread, and folium, leaf.

Habitat:— Growing in skeletal soil of dry watercourses and the sides of gorges. The geology has been described as quartzite for two specimens.

Phenology:— Flowering specimens have been collected September to November; fruiting in late November.

Conservation status:— At present there is little information about the abundance of this species except that there appear to be relatively few collections, and no information on threats e.g. from introduced species. On the other hand it occurs across a relatively large and somewhat under-collected area, with the most distant collection sites ca. 225 km apart. Until more observations become available it can perhaps tentatively be considered as being of Least Concern ( IUCN 2012).

Known distribution:— Endemic to Australia. The species is found in the Rawlinson Range, south-east of the Gibson Desert, Western Australia, and the Petermann and Bloods Ranges, Northern Territory, 200 km west-north-west of Uluru ( Figure 2 ). It should be anticipated also in the Schwerin Mural Crescent, an undulation of hills linking the Rawlinson and Petermann Ranges, although collections have yet to support this.

Notes:— As indicated in the diagnosis, Ozothamnus filifolius appears vegetatively most similar to O. kempei , with which it has previously been confused and which also occurs directly to the east of its known distribution, in the southern third of the Northern Territory. It is possible that O. filifolius evolved out of a marginal population of its common ancestor with O. kempei .

The distribution of Cassinia laevis Brown (1818) overlaps with that of Ozothamnus filifolius . Some of its specimens have been misidentified as the latter, e.g. D.E. Albrecht 9625 (AD!) and R. Bates 58858 (AD!), but it is easily distinguished by its often considerably longer leaves (9–50 mm) and generally ovate as opposed to obovate involucral bracts. Note also that D.E. Albrecht 9625 is a mixed collection, as its NT duplicate is indeed O. filifolius .

Additional specimens examined:— AUSTRALIA. Western Australia: Pass of the Abencerrages, Rawlinson Range , Western Australia, 4 October 1966, A. S. George 8292 ( PERTH 00440914 !). Northern Territory: Livingstone Pass , 13 December 2000, D. E. Albrecht 9625 ( NT A0100592 !) ; c. 20 km due ENE of Docker River , 16 September 2005, D. E. Albrecht 11827 ( NT A0111013 !) ; Mannana Range, 16 January 2008, D. E. Albrecht & P. K. Latz 12493 ( NT D0184683 !) ; Butler Dome summit, 16 October 2010, D. E. Albrecht & P. K. Latz 13574 ( NT D0199460 !) ; Mannana Range , 17 January 2008, T. L. Collins & D. E. Albrecht 427 ( NT D0185142 !) ; Bloods Range , 26 miles NE of Docker River, 19 October 1970, C. Dunlop 1980 (DNA 28628!) ; 0.5 km E Ewalinga Rockhole, Petermann Ranges , 19 September 1969, J. R. Maconochie 778 (DNA A0025067 , PERTH 00440922 !) ; Docker River , November 1970, S. T. Woenne 107 ( PERTH 00503789 !) .

Figures

FIGURE 1. Ozothamnus filifolius, A. flowering heads, B. involucral bract, C. young stem surface, D. bark, E. leaf tip, F. abaxial leaf side hidden by tightly revolute leaf margins (J.R. Maconochie 778, PERTH).

FIGURE 2. Known occurrences of Ozothamnus filifolius (black triangles) and O. vespertinus (black circle). For comparison, the map also shows occurrences of the other species of Ozothamnus covered by the identification key in this paper as sourced from the Atlas of Living Australia (ala.org.au, accessed 4 December 2016): O. blackallii (white triangles), O. cassiope (grey squares), O. kempei (crosses), O. lepidophyllus (grey circles), and O. occidentalis (white squares).