Alloplectus, Alocasia, and Alnus A-Z of Plant genera {16}

Alloplectus weirii

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Foliage of Alloplectus weirii

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Introduction

Here in this series 'A-Z of plant genera', we ;look at the species within certain genera. These species occur throughout the world and a diverse in shape and form and the habitat in which they occur. We review the wild and cultivated species and there are tips on how to grow species that occur in the latter category.

Here in part 16, of the series we look at the species that occur within three genera commencing with the genus Alloplectus. This is a genus of Neotropical plants belonging to the family Gesneriiaceae in the order of plants known as the Lamiales. Recently four species have been moved to the genus Glossoloma and other genera, leaving five in the current genus. Alloplectus aquaticus, Alloplectus hispidus, Alloplectus inflatus, Alloplectus lessmanii and Alloplectus weirii {see header image}.

The cultivars are a group of evergreen,usually summer flowering perennials and sub-shrubs,grown mainly for their flowers and leaves. The loose,prostrate species are better utilized in hanging baskets. They are frost tender with a minimum temperature requirement of between sixteen and eighteen degrees C. They also require partial shade and humus rich,well drained soil. Potted plants need to be watered moderately, less so in low temperatures. They may be propagated by seed in spring or by soft wood cuttings of stem tips in summer. Gardeners need to be aware of and prevent Red-Spider mite and Mealy bug.

Alloplectus nummularia,, sometimes found under Hypocyrta nummularia , is an evergreen perennial with slender,trailing stems,rooting at the swollen nodes. They are only three inches tall with a spread of eighteen inches or more. They have broad,oval to rounded,hairy leaves with toothed reddish margins.

At any time of the year they may produce solitary, tubular, bright red or orange flowers with swollen throats,each with a pouch up to half an inch deep on its lower side, a violet ring in the neck and five very small yellow lobes. They are native to tropical America. This species and its varieties are the ones most popular in cultivation.

Alloplecus penduliforum is a species endemic to Ecuador where it may be encountered in the tropical and sub-tropical mountain forests. It is classed as being Vulnerable by the IUCN. {International Union for the Conservation of Nature}.

Alder trees

Taken at Beaulieu River, Longwater Lawn England
Taken at Beaulieu River, Longwater Lawn England | Source

Alnus viridis is classed as a tall shrub

Taken in Bulgaria.
Taken in Bulgaria. | Source

The genus Alnus

The genus Alnus is placed in the plant family Betulaceae,the Birch family within the order of trees known as the Fagales. Collectively they are referred to as the Alders. The Common Alder Alnus glutinosa has been covered in detail in my article ' Alder-Tree ' ,here on Hub pages,and so is omitted here.

There are about thirty five species of trees and shrubs, a few of them attaining a large size distributed throughout the north temperate zone with a few species extending into Central America, as well as northern and southern Asia, in some parts of the world there are species of Alder that are classed as being Environmental weeds. Many species grow in the USA such as the Red Alder and Sitka Alder. In the USDA many hybrids occur examples are Alnus cordata x glutinosa, Alnus x fallacina,

With a very few exceptions Alders are deciduous trees. The foliage is arranged alternately,simple in form and serrated at the margins.The largest species is the Red Alder Alnus rubra which is encountered on the west coast of North America. Alders are encountered near streams and rivers and in wetlands. The White Alder Alnus rhombifolia,on the other hand has a preference for warm dry climates where it may be encountered along water courses such as along the lower Colombia River east of the Cascades. Most are medium to tall trees, however, the widespread Alnus viridis is rarely more than five meters high and may be classed as a tall shrub.

Alnus serrulata {Tag Alder } Male catkins

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The green immature cones of Alnus incana

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Mature female cones

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The Cultivars.

The Cultivars are a group of deciduous trees and shrubs,grown mainly for their ability to thrive in wet conditions. The flowers are borne in Catkins in late winter or early spring. The male catkins are very conspicuous and attractive. The female catkins form a woody,often barrel-shaped cone which will eventually release the seeds. Most species do best in the sun and any moist or even water-logged soil. However, the species Alnus cordata will also grow well on poor, dry soils.

They may be propagated by seed in autumn,by budding in late summer or by hard wood cuttings in early winter.

Alnus glutinosa variety 'Aurea',is a slow growing deciduous,conical tree. It attains the height of eighty feet with a thirty foot spread. It produces rounded foliage of a bright yellow until mid summer ,later becoming pale green. It bears yellow brown catkins in early spring. It is suitable in a wet or boggy area.

Alnus incana,variety 'Aurea', is a deciduous ,conical tree attaining the height of up to seventy feet with a spread of about twenty five feet. It produces yellow or orange shoots in winter and broadly oval yellow leaves during the spring. The catkins are borne in winter and early spring and are reddish-orange or reddish yellow in colour. It is ideal for cold,wet areas and poor soil.

Alnus 'Ramulis Coccincis',has red winter shoots and buds and orange catkins.


Alders thrive in wetlands

Taken at Wielkie Lake Poland
Taken at Wielkie Lake Poland | Source

Alnus acuminata in South America

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Alnus rubra

Redwood National Park.
Redwood National Park. | Source

Some native species.

Alders are used as a natural firebreak in the USA and other countries since they are much less flammable than coniferous trees. Alders also release nitrogen into the soil which helps other species of trees to grow strong. Alnus acuminata, is a species found in Argentina, Bolivia, Colombia,Mexico, Peru and Venezuela. It attains the height of around eighty feet and produces a straight trunk up to sixty inches {150 cm thick}. The bark is noticeable for its many its many yellowish lenticels { A porous tissue consisting of cells which help to exchange gasses between the internal tissues and atmosphere through the bark.

This species occurs at high altitudes up to one thousand meters in the mountain ranges of tropical and central South America. It is used as watershed protection and to improve the soil, it being a fast growing pioneer species.

Alnus nepalensis, is a species reaching the height of up to ninety feet and is native to the sub-tropical highlands of the Himalayas and is referred to as the Nepalese Alder. The foliage which is round and simple is shallowly toothed and arranged alternatively with each other. They have prominent parallel veins. The male catkins are up to ten inches long the female catkins very much shorter.

It is a fast growing tree which seems to thrive best in deep volcanic loamy soils, however, it is also found on clay and gravelly soils. It grows well in wet areas.

Alnus formosana,referred to as the Formosan Alder is regarded as being a medium sized tree up to sixty six feet in height {twenty meters},and may be encountered from sea level up to nine thousand five hundred feet {2,900 meters}. It is a common species growing along river banks and other water courses.

Alocasia macrorrhiza

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The genus Alocasia

Alocasia, is a genus of plants in the Araceae, within the order of plants known as the Alismatales. They are broad-leaved perennials with rhizomes or tuberous root systems.There are an estimated seventy nine species. These plants are native to tropical and sub-tropical Asia to eastern Australia,and they are widely cultivated elsewhere.

The cultivars are a group of evergreen perennials with underground rhizomes,generally grown for their attractive foliage. They produce tiny flowers on a spadix ,enclosed in a leaf-like spathe {see image above}. they also produce attractive foliage. They are frost tender with a minimum temperature requirement of fifteen degrees C. {59 F}. They also require high humidity,partial shade and well drained soil. They may be propagated by seed,stem cuttings or by division of the rhizomes in spring.

Alocasia cuprea 'portait'

Hawaii Tropical Botanical Garden
Hawaii Tropical Botanical Garden | Source

Alocasia macrorrhiza

Taken on Hawaii
Taken on Hawaii | Source

Some cultivated examples.

Alocasia cuprea,is an evergreen, tufted perennial with oval leaves which are twelve inches long {30 cm}, with a metallic sheen and darker. There are impressed veins above,purple below, with leaf stalks arising from the lower surface. Purple spathes appear intermittently . They attain the height of three feet with a similar spread. This species requires semi-shade and the minimum temperature as previously mentioned.

Alocasia macrorrhiza, is often referred to as the 'Giant Elephant's Ear'. It is an evergreen,tufted perennial,with a thick trunk like stem attaining the height of ten feet or more with a spread of about six feet. They produce broad, arrow-shaped,glossy green leaves up to three feet long, which are carried on stalks of equal length. The spathes are yellowish green up to eight inches tall.

Alocasia veitchii, is sometimes found under the scientific name of Alocasia lowrii,variety veitchii, or Alocasia picta. It is an evergreen tufted perennial of about three feet high with a spread of about thirty inches. They produce narrow triangular leaves with arrow-shaped bases and are about eighteen inches long. They are green with greyish mid-ribs,veins and margins, they have a purplish blue hue beneath. The spathes are greenish.

Alocasia brisbanensis

Taken near the Wilson River NSW, Australia
Taken near the Wilson River NSW, Australia | Source

Alocasia brisbaneensis

Taken at Eastwood , Australia
Taken at Eastwood , Australia | Source

Native species

There follows a brief summary of native species,and where they are found throughout the world. Alocasia acuminata is from Indonesia. Alocasia aequilba is found in New Guinea. Alocasia alba, is found in Sri Lanka. Alocaisa atropurpurea is found in the Philippines. Alocasia brisbanensis [ Pictured above and in fruit to the right} is found in Australia, and is referred to as the 'Spoon Lily'. Alocasia cucullata is found in Indonesia. Alocasia fornica, is found in India and Indonesia. Alocasia hainaica is found from Hainan to north Vietnam. Alocasia infernalis is found in Vorneo. Alocasia odora is native to south eastern China and is referred to as the ' Night scented lily'. And Alocasia sanderiana is native to the Philippines.

Alocasia odora {Night scented lily}

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Be aware.

Most species are poisonous especially in their raw state however, some are edible when cooked, it is prudent to treat them all as being poisonous unless you are positive about their identification and how to use them for culinary purposes. The species in this genus are very similar to some edible plants in other genera that are edible an accidental poisoning has occurred by mistaking the identification of the genera.

For the majority of us they should be treated as attractive ornamental species for the Garden.

Alocasia sanderiana

A wild specimen growing in the Philippines
A wild specimen growing in the Philippines | Source

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4 comments

D.A.L. profile image

D.A.L. 6 months ago from Lancashire north west England Author

Hi Deb,

You are so right ,we must respect all living things we share this planet with. I hope to introduce you to many more plants during this series.Best wishes to you.


aviannovice profile image

aviannovice 6 months ago from Stillwater, OK

There are so many remarkable plants on this earth. We must treat them all with respect, even the common weed, which can be food for those that are hungry.  As always, a wonderful part of your series.


D.A.L. profile image

D.A.L. 7 months ago from Lancashire north west England Author

Hello Devika,

Thank you, your kind comments and tweet are really appreciated. Best wishes to you.


DDE profile image

DDE 7 months ago from Dubrovnik, Croatia

Unique plants! I don't have any of these and looks so pretty. You shared lovely photos and explained in detail. Tweeted!

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