Asteraceae

Asteraceae or Compositae (commonly referred to as the aster, daisy, composite,or sunflower family), is a very large and widespread family of flowering plants (Angiospermae).

The family includes over 32,000 currently accepted species, in over 1,900 genera  in 13 subfamilies.

Nearly all Asteraceae bear their flowers in dense heads (capitula or pseudanthia) surrounded by involucral bracts. When viewed from a distance, each capitulum may appear to be a single flower. Enlarged outer (peripheral) flowers in the capitula may resemble petals, and the involucral bracts may look like a calyx. The name Asteraceae comes from the type genus Aster, from the Ancient Greek ἀστήρ, meaning star, and refers to the star-like form of the inflorescence.

 

Wayside Alien Asteraceae @ Seremban2

SecretGarden of SeriPinang : Compositae

Youngia japonica

Cyanthilium cinereum

Praxelis clematidea

Emilia sonchifolia

Parthenium hysterophorus

Parthenium hysterophorus is a species of flowering plant in the aster family, Asteraceae.   Originated from the American tropics, it is now spread all over the world.  It invades all disturbed land, including farms & plantation, pastures, roadsides, park and gardens in India, Australia, Africa and Asia.

Biology

P. hysterophorus is an annual plant of the Asteraceae family. It normally grows to 30-90 cm in height, but can grow up to 1.5-2.5 m.   It occurs in humid and subhumid tropics, capable to grow on a wide variety of soil types

Flower heads are both terminal and axillary, penduculate and slightly hairy; composed of many florets formed into small white capitula, 3-5 mm in diameter.  Each head consists of 5 -8 fertile ray florets and about 40 male florets.  First capitulum forms in the terminal leaf axil, with subsequent capitula occurring progressively down to stem on lateral branches arising from the axils of the lower leaves.  Thousands of inflorescences may be produced at the apex of the plant during the season.

  

Seeds are black, flattened, about 2 mm long.  A plant can produce about 15,000-25,000 seeds.  Seeds buried in soil can remain viable for at least 4-6 years.  Germination occurred at 10-25°C, over wide range of soil pH.  Germination rate is extremely high.

 

Flowering may begin as early as 4 weeks after germination.  Life circle is about 86 days under optimum conditions, up to 335 days under unfavourable conditions.

Physiological studies have shown that P. hysterophorus has a low photorespiratory activity and has the C3 photosynthetic pathway but with positive C4 tendencies.

Its wide adaptability, photo- and thermo-insensitivity, drought tolerance, strong competition, allelopathy, high seed production, longevity of seeds in soil, small and light seeds that are capable of long distance travel via wind, water, birds, vehicles, machinery, contribute to its rapid introduction worldwide.

Noxious Weed

Parthenium hysterophorus is a vigorous weed that colonises pastures and farms.  Its presence reduce the pasture and crop production, as well as threatening the local biodiversity.

The presence of P. hysterophorus pollen grains inhibits fruit set in tomato, brinjal, bean, etc.

It found its way to India in the 1950s via contaminated wheat imported from the USA.  Today, approximately 2million hectares of land in India have been infested with P. hysterophorus.

P. hysterophorus was introduced to Australia via the movement of military aircraft and machinery during WW2 and pasture seeds.   In Queensland, it is declared a Class 2 plant under the Land Protection (Pest and Stock Route Management) Act 2002.

Health Hazard

P. hysterophorus is linked with several health problems, both in human and domesticated animals.

Contact with P. hysterophorus causes dermatitis and allergic respiratory problems in humans and cattle, due to the presence of toxin parthenin. 

Livestock fed on grass mixed with its leaves too will develop deteriorated quality of milk and meat.

It also causes diarrhoea, severe popular erythematous eruptions, breathlessness and choking.

Benefit

P. hysterophorus is used in its native neotropics as herbal remedy for various intestinal and skin disorders.  It has potential medicinal properties for skin inflammation, rheumatic pain, diarrhoea, urinary tract infections, dysentery, malaria and neuralgia.

Compost produce from P. hysterophorus can lower weed population, possibly due to allelophatic compounds present in it.  The allelophatic substances may be used as insecticide, herbicide, fungicide and nematicide.

Removal of heavy metal and dye from the environment.

Control

Chemical control with glyphosate has found to be unsuccessful.  Paraquat is effective only when the plant is young.  Manual removal can only be done when the population is small.

 

Biological control by leaf-feeding beetle from Mexico, Zygograma bicolorata is reported to be able to defoliate and kill the plant.

Ageratum conyzoides

Ageratum conyzoides ( commonly known as Billygoat-weed, Chick weed, Goatweed, Whiteweed ) is a annual weed originated from tropical America.  Although it is now naturalized locally, it is still not very well known among locals.  

A. conyzoides has little known uses.  It is more being a noxious weed colonizing roadsides, plantations and wastelands. 

Its uses in folk medicine is limited due to its toxicity.  The plant contains lycopsamine and echinatine.  Ingesting A. conyzoides can cause liver lesions and tumors.  There was a mass poisoning incident in Ethiopia as a result of contamination of grain with A. conyzoides.  However, its potentially an plant-based insecticide and nematicide. 

Gnaphalium affine - 清明草

清明草（Gnaphalium affine D.Don）是菊科 (Asteraceae) 鼠麴草属的一种植物，又名鼠麴草、佛耳草、母子草 ，英文名Jersy cudweed。分布在朝鲜、中南半岛、菲律宾、印度尼西亚、印度、台灣、日本以及中国大陆的华南、西北、华东、华中、华北、西南等地。

清明草全株有白色绵毛，叶如菊叶而小，开絮状小黄花，二年生草木，高10～15公分。清明时节，萌生绵绵白毛细叶。

清明草地上部分入药。味甘，性平，止咳化痰，怯風寒，利濕，治久年咳嗽、气喘等症。

清明前后是采摘清明草的好季节，草尖采摘回来洗干净、弄碎，和糯米粉制成糕点，故清明果。