THE ASTERS: SUNFLOWERS

THE SUNFLOWERS

Aster is usually used to refer to most flowering plants with multiple flowering system that appears star-like. They form one of the largest group of plant kingdom. These plants are categorized by Plant Taxonomist as Sunflower, Asteraceae family. Smaller group of the sunflowers are commonly known as the daisy. 

Apart from the daisy, other members of the asters genera may have different common names such as the tasselflower for Emilia, marigold for Tagetes, chrysanths for Chrysanthemum, sunflower, dandelion for many groups.  One major characteristic of asters is that they have a multiple flowering system possessing the head (Capitulum) with their petals reduced into  ray floret (Petalos) of varying shape and size. The disk floret forms a single flower structure but containing multiple floret which come in diverse colour depending on the species. For those members with ray-floret, there is usually a depression at the tip of the floret, that is, the petal-like structure may have some cut in between. The depression can be gentle or sharp given it a lobe of two or three. The number and shape of ray floret differs among species. Some members such as Sunchus and Cicerbita exude latex (sap) but majority of the members don't secrete any sap.

Dispersal
They are dispersed by wind using hairy (pappus) structures to float until they reach a final destination (anemochory) or animal (epizoochory) as they attached to animals using hooks.

Uses

In Nigeria, many of these members occur naturally and can be noticeable at the onset of the dry season in September to December. To many culture, some of the members of the aster are beneficial as animal folder, vegetable or seed used to extract oil for human consumption. Each culture in Nigeria has a unique way of preparing and utilizing many of the plant parts of the aster. Some as ornamental because of their beauteous flowering colour.

Tithonia diversifolia Photo by Elisha ©2016

Guizotia scabra Photo by Elisha; 19 September, 2016

Bidens pilosa Photo by Elisha; 18 October,2016

Galinsoga quadriradiata. Photo by Elish; 18 October,2016

Tridax procumben Photo by Elisha;
18 October,2016

Vernonia adoensis. Photo by Elisha; 18 October,2016

Ageratum conyzoides Photo by Elisha; 18 October,2016

Aspilia Kotschyi Photo by Elisha; 11 August, 2015.

 Aspilia kotschyi Grows in the wild. Leaves are tough with bristles of hairs. Flowers are wine-red in colour. May not easily be differentiated from Aspilia species if not in bloom.

 Bidens oligophora Photo by Elisha; 19 September, 2016

 Bidens oligophora Leaves have a pleasant scent when crushed. Flowers are yellow and becomes brighter towards the tips of the floret. Locally called Abanacha. The leaves of this plant is consumed as a local delicacy(local salad)together with groundnut cake powered.

Tagetes filifolia. Photo by Elisha; 18 September, 2012.

T. triper. Photo by Elisha; 18 September, 2012

T.patula.
Photo by Elisha; 12 August, 2016

 Tagetes species mostly use as ornamental. different species comes with a unique beautiful colour pattern.
Other species of the family asteraceae are:

Zinnia peruviana Pink flower. Photo by Elisha; 19 September 2014

Cosmos sulphureus Photo by Elisha; 11 October, 2014

Emilia sp. Photo by Elisha; 8 September, ‎2016

Emilia sp. Blue-emilia Photo by Elisha; 8 September, ‎2016

Emilia sp. white-emilia. Photo by Elisha; ‎8 September, ‎2016

Emilia fosbergii Photo by Elisha; 8 September, ‎2016

Sonchus oleraceus  Photo by Elisha; 18 October 2016

Cicerbita macrophylla Photo by Elisha; 18 October,2016

Chromolaena odorata Photo by Elisha; ‎19 October, ‎2015

Zinnia peruviana Orange-yellow flower. Photo by Elisha; ‎11 August, ‎2015

Most of them have been reported to be invasive example of that is Chromolaena odorata (Devil's weed) and Tithonia diversifolia.
Before you attempt to use any of these as ornamental make sure you seek a professional advise.

Sources used:
https://en.wikipedia.org/wiki/Asteraceae
Dandelion Taraxacum officinale". Invasive Plant Atlas of the United States. Retrieved 10 September 2012.