Chasmanthe is from the Greek Chasme meaning gaping and anthos meaning flower and refers to the open flowers with their large upper 'petal'.
African Cornflag is a tufted herb with broad, erect sword-shaped and pointed leaves to 1 m long produced annually in winter in a fan-like arrangement from a corm. The flowering stem is up to 1.5 m tall and spike-like with many large orange, red or yellow irregularly shaped flowers which curve downwards and have one petal much longer than the others. It has a 3-branched style and fleshy orange seeds. Native to South Africa, it flowers from winter to spring.
It is similar in appearance to Watsonia and Crocosmia,
Arranged in fan like tufts at the base of the plant. All leaves are of similar size.
Stipules - None
Petiole - None
Blade - Flat, strap like, 400-1000 mm long by 20-50 mm wide. Mid vein prominent and offset from the centre. Hairless. Parallel veins. Tip pointed, sides parallel, base sheathing.
Closed basal sheath.
Stem leaves - small, sheathing and usually 1-3 0n the stem.
Flower stem - erect , robust, circular in cross section, usually unbranched, often purplish. 400-1500 long.
20-30 stalkless flowers on an unbranched, flat spike, 150-300 mm long. Flowers in 2 rows, one on each side of the central and often purplish stem.
Spathe bracts - red brown, small 10-15 mm long, oblong, pointed, shortly divided, membranous, inserted at the base of the ovary. Inner bract shorter than the outer.
Orange-red and yellow or all yellow. Tubular with 6 'petals'. Single within each spathe. Bisexual.
Ovary - Inferior, 3 celled, axial placentation.
Style - slender with 3 thread-like simple branches that are 4 mm long. 3 papillose stigmas. Slightly exerted (i.e. just sticks out of the flower).
Perianth - 50-75 mm long overall, curved. Faintly striped. 30-45 mm long, curved tube is longer than the 6 unequal 'petals'. Tube 35-45 mm overall and is very narrow and twisted for 8-12 mm then abruptly dilated to about 5 mm wide and pouched where it joins the cylindrical upper section. Upper petal is spoon shaped, 18-28 mm long by 8 mm wide and longer than the others which are oblong and 10-17 mm long.
Stamens - 3. Yellow or orange, free filaments with the centre one longer than the other two. Inserted at the base of the wider part of the flower tube. Stick out of flower (exerted) and curved under the upper 'petal'. Grouped to one side of the style.
Anthers - Purple, black or yellow, narrowly elliptic, 7 mm long, versatile with longitudinal slits.
Soft sub-globular, 6 mm long by 3 mm wide, beaked, 3 lobed capsule with 2-4 seeds. Opens from the apex.
Few, globular, orange to red-brown, smooth, sharply angled, shining, succulent.
Flattened corm to 60 mm diameter, covered in a thin net of papery fibres.
Leaves hairless, never longitudinally folded and never abruptly tapered at the base
Inflorescence unbranched, spike-like with many flowers and 1 sessile flower in each spathe that has 2 bracts. Scape occasionally branched.
Flowers persistent, spreading and almost at right angles to the axis
Axis of spike never flexuose (i.e. spike will lay flat)
Style with 3 thread like simple branches.
Spathe valves entire or emarginate
Perianth tube curved and abruptly dilated about 10 mm above the ovary and swollen on one side near the base.
Flowers orange-red and yellow or all yellow.
Perianth lobes unequal with the upper lobe much longer and concave or hooded
Adapted from J. Black, T. James, E. Brown, G. Perry
Perennial. Leaves emerge from the corm in autumn and grow over winter consuming the corm. A new corm is formed on top of the old corm in spring and small cormlets form around the parent corm as the flowering stem emerges. Flowering occurs in late winter to early spring. the leaves and flowers die of with the onset of summer. The corm and cormlets remain dormant over summer and emerge next autumn.
By seed and corms.
July to October in WA.
July to October in NSW.
July to October in SA.
July to October in Victoria.
Seed Biology and Germination:
The yellow flowered form is sometimes listed as Chasmanthe floribunda var. duckittii.
Population Dynamics and Dispersal:
Spread mainly by dumped garden refuse, water and earth moving.
Birds also spread the seed.
Commonly sold at markets or swapped amongst gardeners.
Origin and History:
NSW, SA, TAS, VIC, WA.
Avon Wheatbelt, Geraldton sandplain, Jarrah forest, Swan coastal plain and Warren regions in WA.
Invasive weed of roadsides, bushland and disturbed areas.
It is listed as a "Garden Thug".
Not recorded as toxic.
Management and Control:
Regular mowing or grazing.
Rarely a problem of agriculture.
Grazing provides effective control. Cultivation to 100 mm provides good control if done after the old corm is exhausted and before the new corms form or before the flower stem emerges. A follow up cultivation is usually needed. Mowing and slashing are usually ineffective unless repeated very regularly. Dig up isolated plants and burn the bulbs. Thick infestations are difficult to control manually.
100 g 2,2-DPA(740g/kg) plus 25 mL wetting agent in 10 L of water is the preferred herbicide because it is more selective than 100 mL glyphosate(450g/L) plus 25 mL wetting agent per 10 L water and provides some residual control of seedlings. Apply from flower stem emergence to mid flowering for the best control. Use a sponge glove with 1 L glyphosate(450g/L) plus 2 L water for sensitive areas. Only a few leaves need to be wiped to give good control.
Eradication from an area can usually be achieved in 2-3 years.
Replant shrub and tree species.
Chasmanthe bicolor is naturalised in Victoria and New Zealand.
Plants of similar appearance:
Crocosmia has stolons emerging from the corm.
Watsonia has bulbils on the stem, it flowers later and has its flowers spiralling up the stem rather than in a flat plane.
Native plants which (when not flowering) may be confused with Chasmanthe are: Kangaroo Paws (Anigozanthos species) with darker green, fleshier, unribbed leaves, that are often mottled with dark markings on the older leaves. The dried flower spikes are broad and branched in the common south west Tall Kangaroo Paw (Anigozanthos flavidus).
Patersonia and Orthrosanthus species have leaves which are generally narrower and often bear a few marginal hairs.
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