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Electronic Flora of South Australia genus Fact Sheet

Family: Compositae
Olearia

Citation: Moench, Suppl. Meth. 254 (1802).

Derivation: Probably named after Adam Olearius, 1603-1671, German botanist.

Synonymy: Eurybia Cass., Dict. Sci. Nat. 16:46 (1820); Steetzia Sonder, Linnaea 25:450 (1853).

Common name: Daisy-bushes.

Description:
Shrubs and undershrubs, glabrous or variously hairy, often viscid; leaves cauline, alternate, flat to terete, broadly ovate to linear.

Capitula terminal or axillary, sessile to 1ong-pedunculate, solitary or in corymbs or panicles, usually radiate, heterogamous; involucres cylindrical to broadly hemispherical, becoming slightly spreading or reflexed in fruit; bracts herbaceous with scarious margins, linear to lanceolate, imbricate in 2-6 unequal series; receptacle flat or convex, naked, pitted; ray florets female, uniseriate, usually ligulate, white to blue or purple; style branches narrow-linear, without sterile terminal appendages; disk florets tubular, 5-merous, bisexual, fertile, yellow or mauve; anthers acute to obtuse at the base, with acute apical appendages; style branches linear, flattened, with short acute to lanceolate papillose terminal appendages.

Achenes all similar, terete or slightly compressed, striate; pappus of numerous capillary barbellate bristles, often in 2 unequal series.

Distribution:  About 75 species in Australia and about 25 in New Zealand and New Guinea.

Biology: Olearia asterotricha (F. Muell.)F. Muell. ex Benth., O. myrsinoides (Labill.)F. Muell. ex Benth. and O. slellulata (Labill.)DC. are listed (as Aster species) in Tate (1890) Hdbk Fl. Extratrop. S. Aust. 237 as occurring in the Mt Gambier area. No S. Aust. collections of these eastern species are known to be extant; however, they occur in far south-western Vic. and may once have extended across the border.

Key to Species:
1. Capitula on peduncles exceeding the leaves, solitary or in non-leafy corymbs
 
2. Leaves green and glabrous on the upper surface, white- to rusty-tomentose with centrifixed hairs on the lower surface, distinctly petiolate
 
3. Capitula numerous in corymbs of 2-9; involucres 7-9 mm long, ray florets 5-8
O. erubescens 8.
3. Capitula few, solitary; involucres 15-24 mm long; ray florets 12-30
 
4. Leaf, margins denticulate
O. grandiflora 14.
4. Leaf margins entire
O. pannosa 20.
2. Leaves concolorous, both surfaces glabrous to variously hairy but lacking centrifixed hairs, sessile
 
5. Stems and leaves variously hairy
 
6. Leaves entire, linear, subulate or narrowly oblanceolate
 
7. Leaves 1-1.5 cm long, strongly revolute, scabrous at least on the margins
O. ciliata 6.
7. Leaves 2-5 cm long, flat, densely and softly hirsute
O. picridifolia 22.
6. Leaves lobed or serrate, oblanceolate to obovate
 
8. Leaves obovate, with broad often amplexicaul bases; involucres 2-3-seriate, 8-10 mm long
O. rudis 25.
8. Leaves oblanceolate, with narrowed bases; involucres 4- or 5-seriate, 5-6 mm long
O. stuartii 26.
5. Stems and leaves glabrous
 
9. Leaves compressed-terete, prominently gland-dotted, becoming knobbly in dried material
O. glandulosa 12.
9. Leaves flat (often with revolute margins), smooth in dried material
 
10. Leaves 6-20 mm wide, serrate; ray florets 15-20
O. ferresii 10.
10. Leaves 1-2.5 mm wide, entire or with a few distant lobes; ray florets 3-9
 
11. Stems angular; leaves narrowly oblanceolate, obtuse or lobed at the apex
O. decurrens 7.
11. Stems terete; leaves linear, entire, acute at the apex
O. glutinosa 13.
1. Capitula sessile or on peduncles much shorter than the surrounding leaves, often in a leafy spike or panicle, or solitary
 
12. Woolly hairs absent; plant glabrous
 
13. Leaves flat
 
14. Capitula in a terminal leafy panicle; leaves linear to narrowly oblanceolate
 
15. Stems angular; leaves narrowly oblanceolate, apex obtuse or lobed
O. decurrens 7.
15. Stems terete; leaves linear, entire, acute at the apex
O. glutinosa 13.
14. Capitula solitary, terminal; leaves orbicular to cuneate
 
16. Achenes glabrous; ray florets 14-20
O. magniflora 17.
16. Achenes sericeous; ray florets 8-12
 
17. Involucres 12-18 mm long; leaves all crenate
O. calcarea 5.
17. Involucres 7-10 mm long; leaves entire or some crenulate
O. muelleri 19.
13. Leaves compressed-terete
 
18. Leaves prominently gland-dotted, becoming knobbly in dried material
 
19. Shrub; leaves 10-60 mm long; ligules 3-6 mm long
O. glandulosa 12.
19. Undershrub; leaves 3-20 mm long; ligules 7-8 mm long
O. suffruticosa 28.
18. Leaves without prominent glands, smooth in dried material
 
20. Capitula shortly pedunculate, in corymbs of 2-8 or solitary on remote branchlets; involucres 5-6 mm long; leaves convex below
O. passerinoides 21.
20. Capitula sessile, terminal on branchlets aggregated into a leafy pyramidal panicle; involucres c. 4 mm long; leaves channelled below
O. teretifolia 29.
12. Woolly hairs present on lower surface of the leaves, often also on stems and/or involucres
 
21. Capitula terminal on branchlets which may be aggregated into a leafy panicle
 
22. Stems and upper surfaces of leaves green and densely pubescent with glandular hairs only
O. adenolasia 1.
22. Stems and upper surfaces of leaves glabrous 6r tomentose with whitish non-glandular hairs
 
23. Leaves 3-toothed
O. exiguifolia 9.
23. Leaves entire
 
24. Leaves ovoid, to 1 mm long, closely reflexed against the branchlets in dense rosette-like clusters
O. lepidophylla 16.
24. Leaves oblanceolate to oblong, 1-18 mm long, neither reflexed nor clustered
 
25. Ray floret~ 8-20; involucre 6-8 mm long; leaves 5-18 mm long
O. pimeleoides 23.
25. Ray florets 2-9; involucre 3-5 mm long; leaves 1-4 mm long
 
26. Capitula terminating erect branchlets; disk florets 2-4; leaves approximate, subappressed
O. microdisca 18.
26. Capitula terminating reduced lateral branchlets; disk florets usually 4-8; leaves scattered or in remote clusters, patent
 
27. Leaves obtuse with conspicuous flat whitish- to cream-tomentose lower surface
O. brachyphylla 4.
27. Leaves acute with undersurfaces obscured by the convex whitish-tomentose mid-vein
O. floribunda 11.
21. Capitula axillary, sessile or on reduced shoots much shorter than the subtending leaf
 
28. Leaves 1-2.5 mm long, thickened, ovate, scale-like, crowded in dense clusters along the stems
O. lanuginosa 15.
28. Leaves 4-25 mm long, flat, linear to oblanceolate
 
29. Ligules absent or much shorter than the pappus and style branches
 
30. Leaves 10-30 mm long, 1.5-5 mm wide
O. axillaris 3.
30. Leaves 5-10 mm long, c. 1 mm wide
O. tubuliflora 30.
29. Ligules conspicuous, exceeding the pappus and style branches
 
31. Leaves mostly 5-10 mm long; bristles and/or glandular hairs usually present
O. ramulosa 24.
31. Leaves mostly 10-20 mm long; bristles and glandular hairs absent
 
32. Ray florets 10-15; capitula widely spaced along the stems
O. arida 2.
32. Ray florets 2 or 3; capitula crowded in leafy panicles at the ends of the stems
O. subspicata 27.

Author: Not yet available


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