Ageratum, Aglaonema, Agonis, Agrostemma, Aichryson and Ailanthus. A-Z of Plant genera.

Ageratum houstonianum

Taken in Massachusetts USA.
Taken in Massachusetts USA. | Source

Introduction

This series looks at the species that occurs within specific genera. These plants are diverse in form, size and localities around the world. We review both the native and cultivated species where applicable. Where cultivated plants are mentioned there will be text on their horticultural requirements.

Here we review the species of six genera, and we commence with the genus Ageratum. Ageratum is a genus composed of between forty and sixty species of tropical and warm temperate regions. They are flowering annuals and perennials of the family Asteraceae { formerly Compositae}, and placed in the tribe Eupatorieae. Most of the species are native to Central America and Mexico with five species being native to the USA .In America they are sometimes referred to as White-weed.

The cultivars are a genus of annuals, biennials, which are half hardy. They grow best in fertile well drained soil, which should not be allowed to dry out or the flowering will be poor. Dead head plants regularly to ensure continuous flowering, propagate by seed sown outdoors in the spring.

Ageratum houstonianum

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Ageratum ' cloud nine white'

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Ageratum 'Blue mink'

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Ageratum species

Ageratum houstonianum, is known by the common names of Floss flower , Blue mink, Blue weed, Pussyfoot, and Mexican paintbrush among others. In cultivation it is a moderately fast growing ,hummock forming annual. The tall cultivars have a height of twelve inches. The medium ones a height of eight inches and the small ones a height of six inches. All of them have mid-green leaves and clusters of feathery brush-like flower heads throughout summer and into the autumn. They are all useful as edging plants.

Ageratum Bengali is a medium sized cultivar that produces light pink flowers which deepen in colour with age. Ageratum 'Blue Danube' is small variety and has lavender coloured flowers. Ageratum 'Blue mink', is a medium to tall variety ,fast growing and hummock forming, annual. It has pointed oval leaves and clusters of feathery brush-like pastel blue flower heads in summer and autumn. Agaeratum houstonianum 'cloud nine white' produces white flowers during summer and autumn.


Ageratum conyzoides

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Ageratum conyzoides a native species.

Ageratum conyzoides, has been allocated the common names of Billy Goat weed, and Mexican ageratum, and is a native to tropical America and is most abundant in Brazil, it is classed as being invasive in many other regions where it has been introduced such as Africa, Australia, the southeast Asia and the United States.

This species grows to the height of about two feet and produces pretty pink flowers borne at the tops of trailing stems. it is a species that has been used in herbal medicine however, because of its toxic properties preparations of this species is better left to the professionals.

Aglaonema commutatum

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Aglaonema comuatum this variety is 'Silver Queen'

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Aglaonema costatum showing the spathe

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Aglaonema nitidum

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The genus Aglaonema.

Aglaonema is a genus of flowering plants in the Arum family Aracaeae,,within the order Arismatales. They are native to tropical and sub-tropical regions of Asia and New Guinea. Collectively they are referred to as 'Chinese Evergreens'.

The cultivars are evergreen, erect, tufted perennials, grown mainly for their foliage. They are frost tender ,most species requiring a minimum temperature of fifty nine degrees F {15 C }. They tolerate shade however, the variegated forms need more light. They prefer moist but well drained soils They require moderate watering when in full growth, much less so during the winter. They may be propagated by division or stem cuttings during the summer.

Aglaonema communutatum, is an evergreen, erect,tufted , perennial with a height and spread of up to eighteen inches. It has broadly lance-shaped leaves up to a foot long,dark green with irregular greyish-white patches alon the lateral veins. They produce greenish white spathes in summer.

A.comutatum, 'Silver King' is a cultivar perennial, erect, evergreen, tufted, with a broadly-lance shaped foliage up to a foot long. They are of a mid-green colour marked with dark and light green giving a silver appearance. They produce greenish white spathes in summer. The clump is about eighteen inches high with a similar spread. The minimum temperature requirement is fifteen degrees C { 59 F }.

Aglaonema commutatum ' Treubii' is also an erect,tufted perennial with lance-shaped leaves up to twelve inches long and marked with pale green or silver. Occasionally has greenish white spathes. The height and spread is eighteen inches. it has the same minimum temperature requirement as the previous species.

Aglaonema 'Malay Beauty' { Aglaonema pewter}, is an evergreen perennial with a height and spread of a foot or more. The foliage is oval up to a foot long, very dark green,mottled with greenish white and cream. The greenish white spathe occurs in summer.

The flowers {spathes} of Aglaonema are succeeded by a fleshy berry which becomes red when mature

The rest of the native species belong to a humid,shady, tropical forest habitat,and occur in Vietnam,Thailand, Malayasia, Indonesia, Philippines and Indochina.


Flowers and foliage

Kings Park Perth Australia.
Kings Park Perth Australia. | Source

Agonis flexuosa

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The genus Agonis

The genus Agonis, is placed in the plant family Myrtaceae, and are plants endemic to western Australia,especially near the coast in the south west. They are a genus of evergreen,mainly spring flowering shrubs and trees, grown for their foliage,flowers and graceful appearance as cultivars.

The plants of the genus are noted for their strong smell of peppermint that occurs when the leaves are crushed, however, there are some species that emit the smell of Eucalyptus.

Agonis flexuosa, is also referred to as the Western Australian Peppermint, Swan River peppermint and Willow Myrtle among other comIt is c it. It is commonly grown in parks and on road verges in places such as Perth. In general in grows as a small tree, usually less than ten metres tall. The brown bark is fibrous and the foliage is long and narrow of a dull green colour. From a distance, the tree which has a pendulous habit, looks somewhat similar to the weeping willow.

The small white flowers occur in clusters produced in the axes. It is instantly recognized by the powerful smell of Peppermint which is emitted when the foliage is crushed. It flowers during August until December in its native habitat. The flowers are succeeded by the fruit which is a hard capsule which splits by means of three valves,it contains many seeds.

The cultivar is classed as an evergreen weeping tree. The aromatic lance-shaped foliage are a bronze red colour when young. During the spring and summer the tree carries an abundance of small white flowers. The minimum temperature required is ten degrees C {50 F }. The cultivar attains the height,about thirty feet with a similar spread. They need to be anchored in very well drained soil but moisture retentive, in full sun.

Water containerized plants well in growth but scarcely any water will be needed in winter. Only prune when necessary. They may be propagated by seed.

Agrostemma githago

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Illustration ofthe Corncockle

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Corncockle

Uploaded to Commons via Epibase
Uploaded to Commons via Epibase | Source

Corncockle in its native state

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The genus Agrostemma

This genus must not be confused with the similar sounding Argostemma, which belongs to the family Rubiaceae and the order Gentianales,

Agrostemma, is genus of annual plants in the Carophyllaceae, within the family Carophyllales. many of the species are collectively known and referred to as the Corncockles. The commonest wild species is the 'common' Corncockle, Agrostemma githago. This beautiful little plant was once very common in the wheat fields of the UK and other European countries. It is now rare and its distribution scattered. It is known to be present in other parts of the world through deliberate or accidental introduction, including much of the Untied States and New Zealand,

The loss of this plant in its native regions is a by product of intensive farming,including the use of pesticides and herbicides. Compounding this is the trend to sow winter wheat during the autumn rather than in the spring which was always the traditional way in days gone by. hence the plants and seeds are ploughed in denying them any winter growth or the seeds to germinate.

In the UK the plant was indeed thought to have become extinct until 2014 when a countryside ranger discovered a single plant growing in north east England. other small populations have been established by sowing seed in suitable locations by conservation organisations.

Description of the native Corncockle. It attains the height of three feet or more. The plant produces long lanceolate leaves, and beautiful flowers about two inches in diameter,borne singly at the top of the stems. They are of a deep pink purple colour with white at the base of the petals. Each petal has two or three continuous black lines. Beneath the petals are the sepals consisting of narrow teeth.The sepals are much longer than the petals.

The pale green foliage is arranged opposite to each other and narrowly lanceolate. They are up to five and a half to six inches long. the seeds are produced in a many seeded capsule. The habitat of the native are fields,along railway lines,roadside verges and other waste or undisturbed ground. Although it is poisonous it has been used in herbal medicine {not recommended for home made preparations}.

The cultivars are group of summer flowering annuals. They tend to be fully hardy. They should be placed in the sun and they flower best in well drained soil which is not very fertile. Some ,id not all, will benefit from support provided by sticks. The flowers need to be dead-headed regularly to prolong the flowering period. They may be propagated by seed in-situ, during the spring or early autumn.

The cultivar Agrostemma githago is a fast growing, erect annual with thin stems. The attain the height of two to three feet with a spread of about a foot. They have lance shaped leaves of a mid-green colour during the summer. The five petals form an open trumpet shape and usually pink in colour. These may be up to three inches wide. They are succeeded by a plethora of seeds which are tiny,rounded and dark brown in colour. It should be noted that the seeds are poisonous.

Agrostemma githago variety 'Milas' is a fast growing ,upright, thin-stemmed annual. The foliage is lance-shaped. The flowers are pink-purple three inches wide with five petals produced during the summer. Its height is to to three feet and the spread about a foot. They require a sunny aspect in a not to fertile, but well drained soil.. They are frost hardy.

Agrosttema coeli-rosa has now been placed in the genus Silene.

Aichryson punctatum

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Aichryson laxum foliage

Barlovento La Palma,Canary Islands
Barlovento La Palma,Canary Islands | Source

Aichryson laxum flowers

La Palma , Spain.
La Palma , Spain. | Source

Aichryson bollei

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The genus Aichryson

The genus Aichryson consists of about fifteen species of succulent sub-tropical plants which in the main are native to the Canary islands with a few occurring in the Azores, Madeira and Morocco and one species that occurs in Portugal. They are placed in the family Crassulaceae, and are related to the genus Aeonium.

The succulent leaves are pubescent to densely hairy and the numerous many parted flowers are borne in loose racemes of Sulpher yellow,to greenish yellow star-shaped flowers. In their native state they grow as under-story in the Laurel and Pine Forests of the Canary islands. The soil in which they grow t their best is humus-rich,moist and in a shady aspect.

The cultivars are a genus of annual -biennial and perennial succulents,often shrub-like,grown for their fleshy spoon-shaped to rounded ,hairy leaves. They are generally short-lived,dying after flowering. They are a frost hardy species with a minimum temperature requirement of five degrees C { 41 F }. They require full sun or partial shade ad very well drained soil. They are propagated by seed or by stem cuttings during the spring and summer.

Aichryson aizoides {or domesticum } 'variegatum', is a naturally branching plant and probably an hybrid of garden origin. The rosette of green leaves are margined with yellow and white. Some leaves have random yellow segments.. It produces star-shaped yellow flowers in spring. height up to six inches spread up to sixteen inches.

Aichryson laxum, sometimes found under Semperviren laxium, is a biennial plant from the Canary islands that has also naturalized in Portugal.All parts are pubescent. The foliage tends to become reddened in strong sunlight. They produce many star -shaped flowers of a yellow colour. Unless the flowers are dead-headed the species will die after flowering.

Ailanthus altissima

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Alianthus altissima foliage

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Ailanthus altissima the winged fruits.

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The genus Ailanthus

Ailanthus is a genus of trees belonging to the family Simaroubaceae within the order of plants known as the Sapindales. They are native to east Asia,south to northern Australia. In Botanical Taxonomy {as with other taxonomy], there is often a dispute by authorities ,to the actual number of species that occur within a genus. Ailianthus is one of them.Some authorities accepting ten species,while others will only accept six or even less.

The cultivars a genus of deciduous trees,grown for their foliage and their three to five winged fruits. The foliage is very tolerant of urban pollution. They are fully hardy,requiring sun or partial shade and a deep fertile well drained soil.

Ailanthus altissima, Tree of Heaven, is native of mainland china and Taiwan. However, in Britain and North America it is classed as an invasive species. The tree was first brought to England in the 1740's and the USA,in 1784. Many other countries now play host to this species. gardeners and growers in general lost interest with the native forms because of their suckering habit and the unpleasant smell of the tree which earned it the country names of Stink tree and Ghetto Palm.

The cultivar is a fast growing tree, deciduous and spreading ,attaining the height of eighty feet with a spread of fifty feet. It has large dark green leaves consisting of fifteen to thirty ,paired ,oval leaflets. Large clusters of small green flowers are produced in mid-summer.,which are succeeded by attractive winged fruits that turn reddish brown.

Other species include Ailanthus integrifolia a native to India,Vietnam, and Papuasia. Primarily a species of Rainforests from sea level up to three thousand feet.

Ailanthus triphysa,sometimes referred to as Ailanthus malbariia, occurs in India,Sri Lanka, China, Malaysia, Burma, Thailand,Laos, Philippines,Indonesia and Vietnam. It also occurs in Australia in Queensland and New South Wales.

Other natives include Ailanthus excelsa occurring in India and Sri Lanka. Ailanthus fordi occurring in China. Ailathus vietnamensis-Vietnam. Ailathus tardensis,occurs in a single locality in Hungary, and Ailanthus glgas, from a single locality in Slovenia.

Ailanthus triphysa

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4 comments

D.A.L. profile image

D.A.L. 11 months ago from Lancashire north west England Author

Hi Deb, thank you very much for your kind comments glad you liked this one. It is amazing just how many plants do resemble each other and many from different genera or indeed different families. Best wishes to you.


aviannovice profile image

aviannovice 11 months ago from Stillwater, OK

These are all gorgeous plants, most of which remind me of wildflowers that I have seen in the US, of course exception the silver queen and the trees!


D.A.L. profile image

D.A.L. 11 months ago from Lancashire north west England Author

DDE,

Hello Devika, Thank you so much for your very kind comments which are greatly appreciated. Best wishes to you.


DDE profile image

DDE 11 months ago from Dubrovnik, Croatia

Wow! Beautiful photos and interesting research on these unique names of plants. You know exactly how to put together a well-presented hub.

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