Linola

Linum usitatissimum L.

Family: Linaceae

Names:

Linum is Latin for cultivated flax.
Linola is the name applied to the improved varieties of Linseed.

Other Names:

Flax
Linseed
Linseed Flax.

Summary

Linola are varieties of linseed that have been specially selected for low levels of undesirable acids. It is an erect, thin stemmed, annual herb, which has a single stem that branches near the top. It grows to about 1 m tall with blue or white flowers. Flax is the same species but a different cultivar.

Description

Cotyledons:

Two. Oval. Dull surface. Tip flat to slightly indented. Base tapered. Hairless. No petiole.

Leaves:

Alternate, hairless
Stipules - None.
Petiole - None.
Blade - Bright to yellow green. Parallel sided (linear) to elliptic with a pointed tip. 15-45 mm long x 1-6 mm wide. 3 longitudinal veins. Hairless.

Stems:

Erect, to 1 m tall. Branched near the top, single below. Hairless.

Flower head:

Loose, much branched cyme.

Flowers:

On slender flower stalks (pedicels).
Ovary - Superior. 5 celled.
Style - 5. Free nearly to the base.
Sepals - Overlapping. Ovate, 7-9 mm long. Keeled toward the base with 3 pale veins. The mid vein is most prominent. Tapered tip. Edges are membranous and sometimes have fine hairs.
Petals - Blue or rarely white or pale pink. Egg shaped. 11-13 mm long. Overlapping.
Stamens - 5, alternating with 5 staminodes that are all joined near the base.
Anthers -

Fruit:

Sub globular capsule that splits into 10 single seeded compartments (cocci). 5-8 mm by 7-10 mm. Longer than calyx. Top is pointed.

Seeds:

Brown. Shiny. Flattened. Elliptic. 4-5 mm long.

Roots:

Taproot.

Key Characters:

Annual. Hairless.
Alternate leaves with no petiole.
Flowers blue, white or pale pink.
Petals 11-13 mm long.
Sepals ovate, acuminate, 7-9 mm long, midrib prominent between lateral nerves about half as long.
Styles free except at the base.
Capsule 7-10 mm across.
Adapted from J.R. Wheeler, N.T. Burbidge and John Moore.

Biology

Life cycle:

Annual. Germinates in autumn to early winter. Grows vegetatively until spring when it commences flowering. It dies with the onset of summer drought and high temperatures.

Reproduction:

Flowering times:

Flowers in October to November.

Seed Biology and Germination:

No dormant seed.

Vegetative Propagules:

None.

Ecology, Population Dynamics and Dispersal:

Usually spread by intentional planting, or contaminants of agricultural produce.

Origin and History:

Probably Europe and Asia.
The cultivated Linola was derived from Linseed, which is the same species (L. usitatissimum). It is believed that Linseed was derived from another species L. hologynum.

Distribution:

ACT, NSW, QLD, SA, TAS, VIC, WA.
Widely cultivated throughout temperate Australia.

Courtesy Australia's Virtual Herbarium.

Habitats:

Climate:

Temperate.

Soil:

Prefers well-drained soils.

Plant Associations:

Significance:

Beneficial:

Linen is made from the flax fibres of related cultivars.
Linseed oil is extracted from seeds for human and animal consumption and industrial uses.
Seed meal, left after oil extraction is used as a high protein feed for stock.

Detrimental:

Weed of following crops.

Toxicity:

Toxic. Linseed cake, young crops, screenings, flowers, seeds and wilted plants can be toxic to stock causing cyanide poisoning due to linmarin. The amounts vary depending on the variety, seasonal conditions and methods used for preparation of oils, meals and cake. It tends to be more toxic in warmer climates. The highest levels are in young plants with very little present by the time plants reach 450 mm tall. Flowers after fertilisation and stems appear to have the greatest concentrations. Most poisoning cases are from feeding the meal and cake or grazing young stands, flowers, seeds and wilted plants.
It affects sheep, cattle horses and pigs.
The pressed cake made after extraction of oil occasionally has high levels of HCN. The toxicity of cake depends on method of oil extraction and preparation of the cake. Cake made by hot pressing is rarely toxic.

Symptoms:

HCN toxicity.

Treatment:

Don't allow hungry animals to graze young crops.
Stop feeding or reduce levels of meal and cake in the diet.
Prevent stock grazing linseed.
Affected animals need prompt treatment
Sheep - 1g sodium nitrite and 2g sodium thiosulphate in 15 mL water injected under the skin or into a vein.
 Or 5 mL sulphuric ether under the skin.
 Or 10g sodium thiosulphate (photographic hypo) in 100 mL water given as a drench.
Cattle - 3g sodium nitrite and 15g sodium thiosulphate in 20 mL water injected under the skin or into a vein.
 Or 10 mL sulphuric ether under the skin.
 Or 55g sodium thiosulphate (photographic hypo) in 550 mL water given as a drench.
Legislation:

None.

Management and Control:

Grazing and cropping usually provide control.

Thresholds:

Eradication strategies:

Herbicide resistance:

Related plants:

French Flax (L. trygynum) has yellow flowers.
Purging Flax (L. catharticum)
Wild Flax (L. marginale) has blue flowers with 5 styles united above the middle rather than free.
Yellow Flax (L. flavum)
Linum gallicum

Plants of similar appearance:

References:

Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). 182-183. Photo.

Burbidge, N.T. and Gray, M. (1970). Flora of the Australian Capital Territory. (Australian National University Press, Canberra). P238.

Cunningham, G.M., Mulham, W.E., Milthorpe, P.L. and Leigh, J.H. (1992). Plants of Western New South Wales. (Inkata Press, Melbourne). 436-437. Photo.

Everist, S.L. (1974). Poisonous Plants of Australia. (Angus and Robertson, Sydney). P511-512.

Lazarides, M. and Hince, B. (1993). CSIRO handbook of economic plants of Australia. (CSIRO, Melbourne). #750.5.

Marchant, N.G., Wheeler, J.R., Rye, B.L., Bennett, E.M., Lander, N.S. and Macfarlane, T.D. (1987). Flora of the Perth Region. (Western Australian Herbarium, Department of Agriculture, Western Australia). P463.

Acknowledgments:

Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.