Montag, 31. Oktober 2011

Plant of the Day (October 31, 2011) - Conyza sumatrensis (Retz.) E. Walker)

Happy Halloween!

After I've shown you Conyza canadensis (L.) Crouq. from the Asteraceae family; i want to present you another species of this Genus: Conyza sumatrensis (Retz.) E. Walker, also from the Asteraceae family. Common English names are “fleabane” or “white horseweed”, while in Germany we call it “Weißliches Berufskraut”.

C. sumatrensis - habitus

The species looks similar to C. canadensis an can reach heights until 1 or even 2 metres. It has long, thin leaves, which looks similar to the leaves of a dandelion (however, here the whole shoot is leafy)

The inflorescences are panicles. Like all Asteraceae, these panicles consist of heads, which consist of many radial flowers with five white petals per flower in the periphery and many tubular flowers with five greenish petals per flower in the centre.

C. sumatrensis - inflorescences

So, the radial flowers are simulating a corolla, while their bracts form a fake calyx. These fake flowers are typical for the Asteraceae. It lets the flowers look greater and more attractive for pollinators.

C. sumatrensis - habiuts

Despite it's name, C. sumatrensis is not native to Sumatra but to North America. However, today this species can be found everywhere in world. In Europe it came as Neophyte in the Mediterranean and later to Germany, England or Ireland. It grows at ruderal wastelands, roadsides and between stones. In contrast to C. canadensis, which is the most common species, C. sumatrensis is more rare.

Mittwoch, 26. Oktober 2011

Plant of the Day (October 26th, 2011) - Auricularia auricula-judae Bul. Fr. & Quell.

O.k., Auricularia auricula-judae Bull. Fr. & Quel. is not a plant, but a fungus from the Auriculariaceae family. In Germany it's called “Judasohr” which is also the exact translation of its English name “Judas Ear”. Other common names are “jelly fungi”, “Black Fungus” or (in German) “Hollunderschwamm” (elder mushroom).

A. auricula-judae - habitus (note the shape of an ear)

It's a medium sized fungus with 3 to 10 centimetres in diameter and 2 millimetres in thickness. The convex mushroom (also Karposoma) is nearly ear-shaped, what is also the reason for its name. It has a bright-brown to grey ventral side, while the dorsal site is dark-brown to fleshy-brown. The flesh is tough, gelatinous with a mild flavour and a musty smell of earth. The small spores are white and have a plain surface.

A. auricula-judae - on a branch

This fungus grows on the stems or branches of trees. It's a parasite, which infests weak, death or sick wood. Its primary host is Sambucus nigra L. (Elder), what also gave the species it's name. After his betrayal of Jesus, Judas had hanged himself on a elder tree. It's a cosmopolitan and can be found all over the world and all over the year (it's tolerant towards frost).

A. auricula-judae - habitus

A. auricula-judae is also one of the most popular edible mushrooms of the world and part of many recipe for mushroom dishes; especially in the Asian cuisine, although this fungus has no flavour but for that a pleasant mouth feel.

Sonntag, 23. Oktober 2011

Plant of the Day (October 23th, 2011) - Impatiens glandulifera Royle

Today's entry is about Impatiens glandulifera Royle from the Balsaminaceae family. Its most common German name is “Drüsiges Springkraut” or “Indisches Springkraut”, while in English, you know it as “Himalayan Balsam”.

I. glandulifera - habitus

It's a fast growing, annual plant, that can reach heights until 2 metres (6.56 feet), which is very high for an annual plant. The long leaves are opposite in the lower region of the stalk and whorled in the upper regions. They're oval to lanceolate with strongly serrated edges. Leaf-stalk and the Leaf-base are glandular and covered with many, long stalked glands, what also gave the plant its Latin name (“Glandulifera” means “rich of glands”).

I. glandulifera - stock

Another characteristic feature of this plant are its big, zygomorphous flowers, which are the reason for names like “Wupper orchid”, “Bobby Tops” (based on the helmets of British police officers) or “Gnome's hatstand”. They consists of three sepals and five petals. The lower sepal, which looks like a petal, is extended to a long spur. One petal is much bigger then the rest. The inflorescence is a raceme.

I. glandulifera - flowers, capsules and a bee

Because of their scent and the purple colour, the flowers of I. glandulifera are very attractive for bees, which became the most important pollinator of this species. Another reason are the high content of (average sweet) nectar and the very sweet-tasting pollen.

The fruits are small capsules with many seeds within (between 16.000 and 40.000 seed). These capsules are sensitive to pressure and even the slightest touch (e. g. by a raindrop) is enough to bring them to burst. The seeds are flung away with high speed. This kind of spreading is typical for the genus Impatiens and is responsible for the German name of the genus (“Springkraut” means “jumping herb”)

I. glandulifera - flowers, leaves and capsules

Like its English suggest, I. glandulifera is native to India and the Himalayas but today, it can be found as neophyte also in Europe and North America (it looks similar to an orchid, so it was a very popular ornamental plant). However, today it is one of the most invasive plant of Middle Europe. Because of its fast growing rate and many seeds, I. glandulifera is highly competitive against other species and can displace them easily.

I. glandulifera prefers nutrient-rich and wet soils, so it can be found at riverbanks, ruderal wastelands or the edges of woods and many other places with a high anthropogenic import of nitrogen

Mittwoch, 19. Oktober 2011

Plant of the Day (October 19th, 2011) - Taxus baccata L.

Since the start of this blog, I want to show you a (in my opinion) very interesting tree. However, I waited, because the fruits of this tree are one of its most distinctive features. I'm speaking of Taxus baccata L. from the Taxeaceae family. I'm sure, that you know this plant. In English it's called “European Yew” or often simple “Yew”, while in Germany, we call it “Europäische Eibe”.

T. baccata - habitus (garden tree)

T. baccata is a medium high tree, which can reach heights until 20 metres (65.6 feet), but it can also grow as scrub or bush. The needles are flat and 2 millimetres broad. Their dorsal site is dark green with an emerging leaf-vein, while the ventral site is bright green. The species has a scaly, maroon bark

The species is dioecious with male and female individuals. The male flowers are very small, numerous and with between six and fourteen stames. The ripe pollen are very light and can be spread out by the wind.

T. baccata - (scaly) bark and needles
(note the leaf-vein on the dorsal site)

The female flowers, located at short shoots, are bigger but still very inconspicuous. They consists of scales with one fertile scale at the top of the flower. This scale will form the pollination drop to catch the pollen from the air. Flowering time is very early in the year (between February and March).

T. baccata - red arils

Although T. baccata is a conifer, it has no cones as ripe fruits. Instead, the species forms a small, hard nut, which is wrapped in a red, fleshy “coat”: the so called Aril or Arillus. Its function is the attraction of birds, which eat the sweet-tasting aril and swallow the nut. The nut will be excreted later by the birds. This form of distribution is called Ornithochory. Yeah, I know it sounds disgusting, but it's a very common method of spreading.

T. baccata - short shoots (note the red base)

The roots of this species lay in Middle Europe but it can also be found in Anatolia, the Mediterranean Areas, North Africa and even Scandinavia. It's very undemanding towards its growth conditions and can be found both at acidic and base-rich soils. T. baccata is also very tolerant towards shading.

T. baccata - aril & nut

Through the high content of Taxanes, all parts of T. baccata, except the aril, are highly toxic to humans and the most animals. However, this toxin are harmless to even-toed ungulates (Cows, Deer), which can eat all parts of the tree. As a result, wild yew forest are very rare, because young trees are often eaten by deer before they get a chance to become mature. Curiously, the Taxanes are toxic to odd-toed ungulates (Horses, Donkeys), so T. baccata was opposed by farmers, in order to protect their horses against the venoms. That is another reason why naturally stocks of this tree are very rare today. However, it has become a popular plant for gardens and hedges.

The wood of T. baccata is a heartwood with a dark core. It's very elastic and is used to build bows, some musical instruments or for carving.

Dienstag, 11. Oktober 2011

Plant of the Day (October 11th, 2011) - Ailanthus altissima (Mill.) Swingle

Today, I'll show you Ailanthus altissima (Mill.) Swingle; a tree from the Simaroubaceae family. In English, this plant is known as “Tree of Heaven”, while in German, it's called “Götterbaum” or (rare) “Bitteresche”.

A. altissima - habitus (multi stemmed tree
 that grows from a crack in the wall)

This tree can reach heights between 10 and 30 metres (32.8 and 98.4 feet). The leaves are long (between 0.4 and 3.28 feet) and pinnate. Each leaflet is long-oval too lanceolate with a rough serrated ground.

A. altissima - leave

However, the most distinctive features of the “Tree of Heaven” are the small glands, wich are located at the teeth of the leaflets. This glands secrete sugar water through which the plant attracts ants for pollination

A. altissima - glands (encircled red)

A. altissima has no leaf discolouration. The leaves are falling green.

The species is dioecious, so we've individuals with male or female flowers. Each flower consists of five yellowish green sepals, five yellowish green petals and two circles with five stamens (male) per circle or five carpels (female; some female flowers also have a circle of stamens, but these are sterile). The inflorescences are Thyrses, while the fruits are

A. altissima - treetop

Originally, the natural home of A. altissima China and Vietnam, but during the 18th Century, trees were brought to Europe, Africa and North America as park and garden tree. It's very endurable and tolerant towards air pollution and dryness; so today, you can find the “Tree of Heaven” in many cities, at highways or ruderal wastelands as wild plant. This can also be a problem, because in some regions, A. altissima has become a invasive neophyte.

A. altissima is also the habitat of the caterpillar of the “Ailanthus silkmoth”, so in Asia, this tree is planted for silk production

Donnerstag, 6. Oktober 2011

Field Trip to the City Harbour of Krefeld

About 3 weeks ago, I participated in a little Field Trip to the city harbour of Krefeld, a town in Western Germany. It was a very interesting field trip, because the harbour is located at the river Rhine, which washed a lot of seeds on the shores in this region. Therefore, you can find some very exotic plants in this region. Furthermore, the cobblestones, harbour walls and old railway tracks are an excellent habitat for some interesting plants of special location and ruderal wastelands.

The City harbour of Krefeld

The whole field trip was planed and organized by the “Botanischer Verein Bochum e. v.” (Bochum Association of Botany). I'm not sure, if hot-linking is allowed, so use google to get more informations ;-).

The Town of Krefeld

The Town of Krefeld is located in the state of North Rhine Westphalia in Western Germany. It's part of the so called Lower Rhine region (“Niederrhein”), the last area of the Rhine before it merges into the North Sea.

Rhine Bridge in Krefeld (completed 1936)

The harbour is located in the borough of Linn in the South of Krefeld.


Krefeld was first mentioned in 1105, but the town area had been settled by the Old Romans many centuries before. Here they built a so called castra, a Roman military camp. The village was located on the important “Hochstraße” (High Street) between Cologne and Geldern. After the Third Crusade, the count Otto von Linn built a castle in the region, which exists until today (Linn Castle).

In the Year of 1200, the Lords of House Rode built “Haus Rath”, a toll station on the “Hochstraße”. In the Year of 1373, Emperor Carl the Forth of the Holy Roman Empire gave the settlement of Krefeld its city charter. Krefeld (or Crefeld at this time) was a city now and benefits from better protection against raiders.

This Old Krefeld was destroyed in the Year of 1584 in the “Cologne War” and abandoned for nearly 20 years. In the year of 1594, the countess Walburga sold the land to Moritz of Nassau, Prince of Orangen. As result of this deal, the regions of Krefeld and Moers was declared to neutral counties by Count Albrecht the 7th of the Southern Netherlands. Because of this, Krefeld remained unaffected by the later wars, like the “Thirty Years War” in Germany and the “Eighty Years War” in the Netherlands. So, prosperity could grow over the years and Krefeld became a prosperous city. After the death of William the Third of England in 1702, Krefeld became a part of Prussia.

In the 18th century, a weaving factory were founded by Adolf von Leyen. Von Leyen, also called the “silk baron”, was a religious refugee, who fled into the neutral town to be safe from his pursuers. So, silk weaving became the most important business of Krefeld until the mid-19th century

At the end of the century, Krefeld was occupied by the French Revolutionary Troops under the command of Napoleon Bonaparte, who visited the city 1804. In 1814, Krefeld became a part of Prussia again. The city grew very fast until the 19th century.

After World War I, the City was occupied by Belgian Troops as consequence of the Treaty of Versailles. During this time, Krefeld were shaken by riots of the Rhenish separatists, who fought for the return of the region to Germany. In 1929, Krefeld was united with the surrounding towns like Uerdingen or Fischeln, which became boroughs of the city.

Later Krefeld fell under domination of the Nazis. In November 1939, many synagogues and Jewish stores were devastated during the so called “Kristallnacht” (Night of broken glasses). During World War II, the city was the target of an allied bombing raid in 1943. It was later conquered by the allies.

Today, Krefeld is a town in change, but the textile industry is still a important part of the city. There are also many chemical and steel factories..

Geography & Geology

Krefeld is located at the lower Rhine plains. The soil consists mainly of sand and gravel, which were deposited by the river Rhine over 300.000 year ago. During the last Ice Age, the “Karoo” Ice Age, some of this sand deposits were raised to moraines by the glaciers. An example for such a moraine is “Hülser Berg” in the north.

The main type of soil is the cambisol and the para-cambisol; both are very fertile soils and a good base for agriculture. In addition, a lot of loess were deposited in the western areas of the town, which is a very fertile sediment. There are also some stagnosols.


The region has a temperate climate, with an annual rainfall of about 759 Millimetres and an average degree of 10° Celsius (about 50° Fahrenheit)


The area of the field trip is a typical example for ruderal wastelands or an industrial fallow. We have boulders, walls as well as a rocky shore and dykes. All these places are a potential habitat for plants, especially for “specialists”, which can endure the hot temperatures of the stones and the small deepness of the soil. They grow e.g. in cracks, chinks or between the rocks or even on the way..

Species list

Lecanora muralis (Schreb.) Rabenh.
Arenaria serpyllifolia L.
Catalpa agg. Spoc.
Tanacetum vulgare L.
Calystegia sepium (L.) R. Br.
Stachys palustris x sylcatica L.
Festuca nigrescens Lam.
Acer saccharinum L.
Acer platanoides L.
Acer campestre L.
Rumex salicifolius var. triangulivalvis (Danser) Hickman
Bunias orientalis L.
Solanum nigrum L.
Scrophularia umbrosa Dumort.
Scrophularia nodosa L.
Campanula rotundifolia L.
Impatiens glandulifera Roye
Galium agg.
Medicago lupulina L.
Ricinus communis L.
Populus alba L.
Poa compressa L.
Betula pubescens Ehrh.
Ailanthus altissima (Mill.) Swingle
Cymbalaria muralis Gaertn., Mey. Et Scherb
Betula pendula Roth.
Eupatorium cannabinum L.
Cornus sanguinea L.
Wisteria agg.
Diplotaxis tenuifolia (L.) DC.
Rubus laciniatus Willd.
Humulus lupulus L.
Rumex scutatus L.
Prunus malaheb L.
Ulmus minor Mill.
Vitis vinifera ssp. Sylvestris (C. C. Gmel) Hegi
Sorbus intermedia (Erh.) Pers.
Laburnum anagryoides Medik.
Sedum sexangulare L.
Berteroa incana (L.) DC.
Buddleja davidii Franch.
Medicago x varia Martyn
Carduus acanthoides L.
Echium vulgare L.
Origanum vulgare L.
Ficus carica L.
Oxalis fontana L.
Conyza summatrensis (Retz.) E. Walker
Celtis australis L.
Trisetum flavescens (L.) P. Beauv
Lepidium latifolium L.
Sedum samentosum Bunge.
Erigeron anuus (L.) Pers.
Cardamine impatiens L.


Lecanora muralis (Schreb.) Rabenh
Carduus acanthoides L. (welted thistle)
Ailanthus altissima (Mill.) Swingle - Tree of Heaven

Berteroa incana (L.) DC. - Hoary Allysum
Campanula rotudifolia L. - harebell
Conyza sumatrensis (Retz. ) E. Walker - white horsweed, fleabane

Cymbalaria muralis Gaertn., Mey. Et Scherb - Kenilworth Ivy

Echium vulgare L. - Viper's bugloss or Blueweed

Eupatorium cannabinum L.

Ficus carica L. - common fig

Humulus lupulus L. - common hop

Impatiens glandulifera Royle - Himalayan balsam

Origanum vulgare L. - oregano

Oxalis fontana Bung

 Prunus mahaleb L. - Mahleb, Mahaleb Cherry, Rock Cherry

Riccinuns communis L. - castor oil plant

Rubus laciniatus Willd. - Cutleaf Evergreen Blackberry

Rumex salicifolius var. triangulivalvis (Danser) Hickman - willow sorrel

Rumex scutatus L.  - shield sorrel
 Scrophularia umbrosa Dumont - green figwort

 Solanum nigrum L. - black nightshade
 Stachys palustris x sylvatica

Ulmus minor Mill. - field elm

Dienstag, 4. Oktober 2011

Plant of the Day (October 4th, 2011) - Oenothera glazioviana Micheli.

This time, I want to give you an basic overlook about the species Oenothera glazioviana Micheli from the Onagraceae (Willoherbs) family. The common English name of this plant is “Large flowered evening Primrose” or “redsepal evening primrose”, while in German, this plant is known as “Rotkelchige Nachtkerze”.

O. glazioviana - habitus

It's a herb, that can reach heights until 1,8 metres (5.9 feet), but it's often smaller (between 1 metre or 3.3 feet). Stem and floral axis are covered with many small hairs. Each hair has a bulbous, red base, so the plant seems to be speckled red. The alternate leaves are elliptical and are sitting directly at the stem. They're a little bit humpy.

The inflorescence is a single, terminal raceme. The flowers are very big. The sepals are fused together to a long tube at their base and have long, red tips, while the large petals are yellow and between 40 and 50 Millimetres long. As with all species from the Onogaraceae, one “level” of flowers blooms per night, from the bottom to the top of the floral-axis.

O. glazioviana - flowers (here
you can see the red tip on the
 back of the flower tube)

This plant is native to Europe, but it is a hybrid between the two North American species Oenothera elata Kunth. and Oenothera biennis L. Both plants were planted in European gardens and interbreed to form this new species, which became wild. It grows on nutrient-rich soils and can be found on roadsides, ruderal wastelands or slopes. It can easily be identified by its large flowers with the red speckled sepals.