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flowers, foliage

flowers, foliage

Natural populations

Eremophila maculata is a perennial shrub less than 2 m tall that inhabits eucalypt or Acacia woodlands or mixed chenopod/Eremophila shrublands. It grows mainly on well-drained heavy clay or clay loams and duplex soils on the floodplains, valley floors, saline drainages and around lakes [2, 11, 13, 17, 18]; and as such is subject to periodic flooding. It is tolerant of alkaline and often saline environments and is rarely seen in non-saline environments [18]. Three subspecies are recognised by Chinnock [5]:

Occurrences of subsp. brevifolia are also reported from Coolgardie and the Nullabor Plain (pers. comm. Andrew Brown, Department of Environment and Conservation, Western Australia].

Flowering and seeds

Red, pink, orange, yellow and white flowers can occur in a single population of subsp. brevidolia [pers. comm. Andrew Brown, Department of Environment and Conservation, Western Australia]. Red, orange, yellow and pink flowers are exhibited by subsp. maculata [37]. Flowering can occur all year round.

Eremophila seed in general has been found to be difficult to germinate by propagators. Plants are generally reproduced from cuttings. The hard woody fruits have physical and chemical inhibitors that delay germination [122]. Seed germination is greatly improved once it is excised from the hard fruit covering [122] with some difficulty in the case of E. maculata [123]. Natural weathering processes of fire, wet and dry seasonal cycling and abrasive soil movement will eventually break down hard fruit coats and stimulate germination [122].

Excised seeds from the woody fruits of E. maculata are recorded with a high rate of germination of up to 98% within 150 days [74]. The chemical inhibitors and hard seed coat act to restrict seedling emergence after fruiting during the summer months [74]. These inhibitors are leached by seasonal rains (or fires), so germination is postponed until a good wet season [74].

Cultivation and uses

The plant is an Aboriginal medicine, and is used as an ornamental [2, 17]. Cattle and sheep regularly eat the plant in large amounts and it is regarded as a good fodder plant [13], though it can be poisonous to stock under stress of droving or drought [13, 14]. It is one of the most strongly cyanogenetic plants known and as little as 30g of leaf will kill a sheep; however stock seem to eat it with impunity in the normal grazing situation [17; 18]. It is an indicator of fair range condition – it will thicken up under heavy grazing and will be eliminated under very heavy grazing [18].

Key descriptors:
Subsp. brevifolia:
Climate parameters
Mean annual rainfall: 200-300 mm
Rainfall distribution pattern: winter
Mean annual temperature: 15-30 °C
Mean max. temperature of the hottest month: 35-40 °C
Mean min. temperature of the coldest month: 4-12 °C
Frosts (approx. no. per year): greater than 20
Frost intensity: light to moderate (0 to -5°C)
Altitude: 50-550 metres
Soil factors
Texture: clay loam, light to medium clay (35-50% clay), loam, sandy loam, sandy clay loam or sand
Drainage:  seasonally waterlogged
Salinity: slightly to moderately saline
Biological traits under cultivation
Habit: evergreen shrub less than 2 m tall, shrub or small tree less than 5 m tall or tree 5-10 m tall
Longevity: moderate to long lived (>15 years)
Potentially undesirable attributes
Foliage: cases of stock poisoning have been reported
Subsp. filifolia:
Climate parameters

Mean annual rainfall: 300-300 mm
Mean annual temperature: 13-40 °C
Mean max. temperature of the hottest month: 40-40 °C
Mean min. temperature of the coldest month: 13-13 °C
Frosts (approx. no. per year): frost free or more or less frost free
Altitude: 100-100 metres
Soil factors
Texture: sand
Drainage: well-drained
Biological traits under cultivation
Habit: evergreen shrub less than 2 m tall, shrub or small tree less than 5 m tall or tree 5-10 m tall
Longevity: moderate to long lived (>15 years)
Potentially undesirable attributes
Foliage: cases of stock poisoning have been reported
Subsp. maculata:
Climate parameters
Mean annual rainfall:  100-700 mm
Rainfall distribution pattern: summer, uniform or winter
Mean annual temperature: 12-27 °C
Mean max. temperature of the hottest month: 31-38 °C
Mean min. temperature of the coldest month: 2-8 °C
Frosts (approx. no. per year): 3. greater than 20
Frost intensity: light to moderate (0 to -5°C)
Altitude: 0-350 metres
Soil factors
Texture: clay loam or light to medium clay (35-50% clay)
Soil pH reaction: alkaline (greater than 7.5)
Drainage:  seasonally waterlogged
Salinity: slightly to moderately saline
Biological traits under cultivation
Habit: evergreen shrub less than 2 m tall, shrub or small tree less than 5 m tall or tree 5-10 m tall
Longevity: moderate to long lived (>15 years)
Potentially undesirable attributes
Foliage: cases of stock poisoning have been reported

References

[2] Carr D (2000) Plants in Your Pants II: a pocket guide to the trees and shrubs of the North West Plains of  NSW. Greening Australia NSW, Armidale.

[3] Latz Peter K (1995) Bushfires and bushtucker: Aboriginal plant use in Central Australia. IAD Press, Alice Springs.

[5] Chinnock RG (2007) Eremophila and Allied Genera: a monograph of the plant family Myoporaceae. The Botanic Gardens and State Herbarium, Department of Environment & Heritage, Government of South Australia.

[11] Kent K, Earl G, Mullins B, Lunt I, Webster R (2002) Native Vegetation Guide for the Riverina: notes for land managers on its management and revegetation. Charles Sturt University, NSW.

[13] Petheram RJ, Kok B (1986) Plants of the Kimberley Region of Western Australia. Department of Agriculture, Western Australia.

[14] Stanley TD, Ross EM (1983 to 1995) Plants of South-East Queensland. Volumes 1-3, Queensland Government, Brisbane.

[17] Cunningham GM, Mulham WE, Milthorpe PL, Leigh JH (1992) Plants of western New South Wales. Inkata Press, Port Melbourne, Victoria.

[18] Mitchell A, Wilcox D (1994) Arid shrubland plants of Western Australia. University of Western Australia Press, Perth.

[37] Paczkowska G, Chapman AR (2000) The Western Australian Flora - A Descriptive Catalogue. Publishers: Wildflower Society of Western Australia, Western Australian Herbarium, CALM and the Botanic Gardens and Parks Authority,Western Australia.

[74] Richmond GS, Chisalberti EL (1994) Seed dormancy and germination mechanisms in Eremophila (Myoporaceae). Australian Journal of Botany 42, 705-715.

[122] Cochrane A (2002) Seed notes for Western Australia: Eremophila. 4p Pamphlet No. 5, Wildflower Society of Western Australia, Perth Branch, Nedlands..

[123] Rezl A (1996) A study of Eremophila seed germination. Association for Societies for Growing Australian Plants (Online resource) http://asgap.org.au/eremoph1.html (Accessed: February 2008).

Internet links

PlantNet NSW Flora Online – species description & distribution: http://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Eremophila~maculata

FloraBase Western Australia Flora Online – species description & distribution: http://florabase.calm.wa.gov.au/browse/profile/7237;http://florabase.calm.wa.gov.au/browse/profile/16363

http://florabase.calm.wa.gov.au/browse/profile/18050;http://florabase.calm.wa.gov.au/browse/profile/16362

Australian Journal of Botany: http://www.publish.csiro.au/paper/BT9940705.htm

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