Electronic Flora of South Australia
Electronic Flora of South Australia
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Electronic Flora of South Australia genus Fact Sheet

Family: Myrtaceae

Citation: L., Syst. Nat. edn 12, 2:509 (1767).

Derivation: Greek melas, black; leucon, white; alluding to the contrasting colours of the bark.

Synonymy: Not Applicable

Common name: Melaleucas.

Trees or shrubs; leaves spiral, decussate, or rarely verticillate, entire, flat or compressed or terete, 1-7-nerved.

Flowers mostly bisexual, rarely unisexual and then usually with male or female flowers as well as bisexual flowers on the same plants, in monads or triads in spikes or dense heads with scarious deciduous bracts and bracteoles, or sometimes in leaf axils; hypanthium cup-like, adnate to the ovary at the base; sepals 5, short, rounded or triangular, more or less continuous with the hypanthium; petals 5, orbicular usually with a short claw; stamens 15-400, longer than the petals, united into 5 bundles opposite the petals, usually white, yellowish, greenish or red; anthers versatile; ovary 3-celled, with several to many erect ovules in each cell; style filiform; stigma simple.

Fruit a capsule enclosed in the more or less woody hypanthium, opening loculicidally at the summit.

Distribution:  About 220 species, mostly Australian.

Biology: No text

Taxonomic notes: The genus is currently under revision. This treatment is based on J. Carrick & K. Chorney (1979) J. Adelaide Bot. Gard. 1:281-319 in which all S.Aust. species are illustrated.

Key to Species:
1. Leaves decussate
2. Flowers in clusters of 2-6 on a very short axis
3. Flower clusters single, axillary or lateral on old stems
4. Stamen filaments pink
M. wilsonii 21.
4. Stamen filaments white or yellow
5. Leaves linear-lanceolate, thickened and punctate-glandular at the margin
M. oxyphylla 15.
5. Leaves narrow-elliptic, not thickened at the margin, punctate-glandular below
M. acuminata 1.
3. Flower clusters grouped in small heads at the ends of the stems
M. halmaturorum 9.
2. Flowers in spikes on an elongated axis
6. Mature fruits immersed in an inflated infructescence axis
7. Leaves linear to oblanceolate, 5-15 mm long
M. decussata 5.
7. Leaves ovate to obovate, 2-6 mm long
M. gibbosa 8.
6. Mature fruits not immersed in an inflated infructescence axis
8. Flowers in triads
9. Leaves linear; inflorescence axis only very rarely growing on
M. eleutherostachya 7.
9. Leaves ovate; inflorescence axis growing on
M. squarrosa 19.
8. Flowers in monads
10. Fruit subglobular, 3-5 mm diam
M. linariifolia 12.
10. Fruit urn-shaped, 7-9 mm diam
M. corrugata 4.
1. Leaves alternate or verticillate
11. Leaves c. I mm long, scale-like, peltately attached
M. nanophylla 14.
11. Leaves 3 mm long or more, not scale-like, attached at the base
12. Flowers in lateral clusters of 1-6 on a very short axis which does not grow on
M. brevifolia 3.
12. Flowers in terminal spikes or heads; axis growing on during or after flowering
13. Fruits more or less compressed in dense globular heads
14. Flowers white or yellow, in triads; leaves more than 10 mm long
15. Leaves terete, with a curved point
M. uncinata 20.
15. Leaves flat, with a straight point
M. glomerata 9.
14. Flowers pink to purple, in monads; leaves less than 10 mm long
M. squamea 18.
13. Fruits in spikes or loose clusters, not compressed
16. Mature fruits partly immersed in an inflated infructescence axis
M. rhaphiophylla 17.
16. Mature fruits not immersed in an inflated infructescence axis
17. Stamens mostly in bundles of more than 15, with a claw more than 2 mm long
18. Stamens 15-25 in each bundle
19. Leaves more than 15 mm long
M. dissitiflora 6.
19. Leaves less than 15 mm long
M. bracteata 2.
18. Stamens 30-60 in each bundle
M. linariifolia 13.
17. Stamens mostly in bundles of fewer than 15, with a claw less than 2 mm long
20. Fruits more than 6 mm diam
M. leiocarpa 12.
20. Fruits less than 6 mm diam
21. Flowers in monads; leaves compressed to sub-terete
M. pauperiflora 16.
21. Flowers in triads; leaves flat
M. lanceolata 11.

Author: Prepared by B. A. Barlow

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