An erect annual or biennial herb to 600 mm tall with a basal rosette of stalked leaves and a single stem with clasping leaves, branched at the top to carry many 2 seeded pods held at right angles to the stem.
Description:
Cotyledons:
Two. The blade is 5-8 mm long with a petiole 3-5 mm long, and is hairless. The seedling has a long hypocotyl but no epicotyl.
First leaves:
The leave arise singly, but the first two appear almost at the same time and superficially appear to be paired. The early leaves are 6-10 mm long in the blade with a petiole of the same length.
Leaves:
The plant forms a loose rosette that is not persistent
Stipules -
Petiole - Yes. Hairy.
Blade - Elongated egg shaped and up to 70 mm long. Tip rounded. Sides toothed, shallowly lobed or smooth and convex. Surface densely hairy.
Stem leaves - Narrowly triangular, 30-100 mm long by 30-100 mm wide. Tip pointed. Edges smooth or toothed and straight angular. Base sessile and clasping. Surface densely hairy.
Stems:
Solid, circular in cross section, 200-600 mm tall and carries short hairs. The stems branch from about half way up, but have few or no branches from the base.
Flower stem -
Flower head:
The inflorescence is terminal and forms an elongated cone (elongated raceme).
Flowers:
4-5 mm in diameter.
Ovary -
Sepals - 1.5 mm long.
Petals - 4, white, 2-3 mm long.
Stamens - 6.,
Anthers -
Fruit:
Flattened, 2 seeded, pendulous, broadly egg shaped, notched capsule, 5-6 mm long by 4 mm wide and covered with scale like vesicles when dry. The capsule has 2 wide wings and is carried on a horizontal stalk (pedicel) that is 5-6 mm long. The seeds are released from the capsule when ripe.
Seeds:
Roots:
Taproot.
Key Characters:
Biology:
Life cycle:
Annual or biennial. Germination occurs in autumn and spring.
Physiology:
Reproduction:
By seed.
Flowering times:
Seed Biology and Germination:
Vegetative Propagules:
None.
Hybrids:
Allelopathy:
Population Dynamics and Dispersal:
Origin and History:
Europe.
Distribution:
NSW, TAS, VIC.
Found in many parts of Tasmania, but is somewhat local and restricted in its distributions.
Habitats:
Climate:
Temperate.
Soil:
Plant Associations:
Significance:
Beneficial:
Detrimental:
Weed of crops and disturbed areas.
It is capable of being competitive.
Toxicity:
Not recorded as toxic.
Legislation:
None.
Management and Control:
Thresholds:
Eradication strategies:
Most of the Brassicaceae weeds have dormant seeds that continue to germinate throughout the season and for several years. They often mature and set seed very quickly. Manual removal is effective but must be done at least every 8-10 weeks. Once pods are formed, seed will often mature even if the plant has been uprooted. Soil disturbance often leads to a flush of seedlings.
Many are somewhat unpalatable, so grazing only offers partial control. They often flourish in undergrazed, sunny areas.
In bushland situations, fairly selective control can be achieved with 100 mL spray oil plus 0.1 g Eclipse® or 0.5 g Logran® in 10 L water. 5 mL Brodal® is often added to this mix to provide residual control of seedlings. Spray the plants until just wet from the seedling stage up to pod formation.
Isolated plants should be removed manually and burnt if flowering or seeding and a 10 m buffer area sprayed with 10 mL Brodal® in 10 L water.
500 mL/ha of glyphosate(450g/L) can be used at flowering to reduce the seed set of most species on roadsides without causing significant damage to most native plants.
Wick application with 1 part glyphosate(450g/L) in 2 parts water or overall spraying with 100 mL glyphosate(450g/L) in 10 L water provides reasonable control of most species though Wild Radish tends to regrow.
Herbicide resistance:
Biological Control:
Related plants:
Argentine Peppercress (Lepidium bonariense)
Common Peppercress (Lepidium africanum)
Garden Cress (Lepidium sativa)
Matted Peppercress (Lepidium pubescens)
Peppercress (Lepidium hyssopifolium) has stalked stem leaves and is shorter.
Perennial Peppercress (Lepidium latifolium)
Virginian Peppercress (Lepidium virginicum)
(Lepidium oxytrichum)
(Lepidium perfoliatum)
There are 27 native species of Lepidium.
Plants of similar appearance:
Field Cress is generally similar in appearance to Hoary Cress (Cardaria draba) but can be distinguished from it in the mature stage by the lack of a perennial spreading root system. In Field Cress the inflorescence is elongated, frequently carrying flowers towards the top and seed at the bottom, while in Hoary Cress the inflorescence tends to be umbrella shaped and broad and spreading. The fruits and distinctive. The seedlings are very similar and not readily separated. In Field Cress the cotyledon is more rounded and the leaf is only bluntly pointed or rounded at the tip and without lobes, while in Hoary Cress the first leaves tend to be pointed and have small but distinct lobes.
References:
Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). P134.
Harden, Gwen J. (1991). Flora of NSW. (Royal Botanic Gardens, Sydney). Volume 1. P468. Diagram.
Hyde-Wyatt, B.H. and Morris, D.I. (1975). Tasmanian weed handbook. (Tasmanian Department of Agriculture, Hobart, Tasmania). p49.
Lamp, C. and Collet, F. (1990). A Field Guide to Weeds in Australia. (Inkata Press, Melbourne).
Lazarides, M. and Hince, B. (1993). CSIRO handbook of economic plants of Australia. (CSIRO, Melbourne). #735.3.
Acknowledgments:
Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.