Freitag, 24. Mai 2013

Species of the Day (May 25th, 2013) - Cepaea hortensis O. F. MÜLLER, 1974

This time, I want to present you another animal. This animal is Cepaea hortensis O.F. MUELLER; a snail from the Helicidae family, which belongs to the order of the Pulmonata. The Pulmonata are one of the classic orders of snails (Gastropoda). It includes all snails with “lungs” instead of gills. The Taxonomy is

  • Mollusca (“Molluscs”)
  •   -> Gastropoda (“Snails”)
  •     -> Pulmonata (“Terrestrial Snails with lungs”)
  •      -> Helicidae
  •       -> Cepaea ("banded snails")
  •         -> Cepaea hortensis

*) please note: this is the old taxonomy, but you still find this in many books.

In English, the species is known as “white-lipped banded snail” and in German as “Garten-Bänderschnecke”.

1) Description

C. hortensis - habitus

C. hortensis is a small snail, which can reach a maximum length of 12 centimeters. Its body has a white or silver-white color with a dark stripe on the back. As all snails, the species has four antennas (two short and two long). The eyes are located at the end of the long antennas.

C. hortensis - head with antennas and eyes

The shell has a white aperture (“Mündung”), what is an distinctive feature of this species and the reason for its name. In some rare cases, the aperture may be brown, but this is a mutation

C. hortensis with white aperture (right side)

As with the most snails from the Helicidae, the shell of C. hortensis is spherical. It also has a high variation in color. In the most cases, the shell is dull yellow with brown stripes but shells without stripes are also very common (as on my picture). Some snails even have a brown shell.

C. hortensis - shell (side view)

The measurements of the shell are 16 millimeters in height and 22 millimeters in diameter. It has between 5 and 5.5 convolutions.

C. hortensis is a hermaphrodite; so it has a male and a female reproductive system. If a snail meets a sexual partner, one animal works in its love dart (Gypsobelum) to inseminate the partner. The Gypsobelum of C. hortensis has several glands, what is another distinctive feature of this species.

C. hortensis - view into the aperture
Self-fertilization is also possible, but not very common

C. hortensis is closely related to Cepaea nemoralis (brown-lipped snail). As the name suggest, the aperture of C. nemoralis is brown, what is a good differential between these two species (as long as you haven't the variation with a brown aperture).

2) Distribution & Biology

The white-lipped banded snail is native to Europe and can also be found in North America as neophyte. It colonized a wide range of different habitats like grassland, woods, gardens, parks and so on.

C. hortensis - shell (aperture is black by dirt)

C. hortensis lives in dense vegetation. The most time of the day, the snail rest in its shell. When active, the species searches for food. It eats plants like hogweed, ragwort or nettles. However, the species isn't a vermin and no hazard for gardens or ornamental plants.

C. hortensis - variant without black stripes

The natural enemies of C. hortensis includes all predators, which are able to break the shell. A special predator is the Song Thrush (Trudus philomelos; “Singdrossel” in German). This birds cracks the shell by throwing it on rocks and stones. Around such stones, you can find the remains of shells of C. hortensis

Mittwoch, 15. Mai 2013

Field Trip to Wanne-Eickel (May 5th, 2013)

Last week, I participated in a Field Trip to the Rhein-Herne Canal in Wanne-Eickel (NRW). The focus of this Field Trip lay on the early vernal plants and plants of ruderal wastelands and urban areas.

Welcome to Wanne-Eickel

1) The Rhine-Herne Canal

The Rhine-Herne Canal was built between 1908 and 1914. It's a transportation channel, which connects the River Rhine in Duisburg with the Dortmund-Ems Canal. The channel has a total length of 45.4 kilometres and runs nearly through the whole Ruhr region and parallel to the river Emscher. Thereby, the freight of the ships, which travel on the channel, consists of coal, ore, scrap and other products, which are characteristic for mining industry and heavy industry. 

 Rhein-Herne Canal at Wanne-Eickel

Because the channel has to overcome a difference in altitude of nearly 35 meters, there are five locks along the course. These locks are located in East Herne, Wanne-Eickel, Gelsenkirchen, Oberhausen and Duisburg. Earlier, there were even seven locks until 1991.

Southern lock in Wanne-Eickel

The lock in Wanne-Eickel, which you can see on my pictures, is located in Crange, an urban district of Wanne-Eickel respectively Herne (s. below). It overcomes a height difference (“Fallhöhe” in German) of nearly 8,50 meters.

Old Norther lock
The complex consists of two locks, which were built in 1906. However, the northern lock was defunct later and today, only the southern lock is operational. The southern lock was renewed in 1994, because it became to small for the modern cargo ships of the “Europa II” class.

Flood gate of the Southenr Lock

The new lock has an effective length of 190 meters and an effective width of nearly 12 meters. The old northern lock has still its old measurements with a length of 163 meters and a width 10 meters. This is to small for modern ships.

In addition, the renovation of both locks is planned for the future.

2) Wanne-Eickel and Crange

Wanne-Eickel is a small town in the heart of the Ruhr Region in Northrhine Westphalia (Western Germany). More specifically, Wanne-Eickel consists of two villages: Wanne and Eickel, which fused in 1926. Because of its position, Wanne-Eickel was a centre of mining (especially coal and ore) and an important junction for the industry in this area. The main station of Wanne-Eickel was one of the largest railway yard of the Ruhr Region. 

Church in Crange

In 1975, Wanne Eickel merged with the small town of Herne. This was the birth of the new Herne, with Wanne and Eickel as two separated, urban districts. However, Wanne-Eickel exists until today for many people as an own town. The main station still bears the name “Wanne Eickel Hbf” (Wanne-Eickel Mainstation).

Powerplant in Wanne-Eickel

The reason for this is the high popularity of Wann-Eickel in popular culture. It symbolizes a typical, medium town in the Ruhr region with Industry as formative factor and inhabited by simple people and miners.

The most famous cultural heritage is the song “Mond von Wanne-Eickel” (“Moon over Wanne-Eickel”) by Friedel Hensch and his band.

Mining Industry - Coal sorting machine

Another examples are the fictional resident “Adolf Tegtmeier”, which was created by the famous German comedian Jürgen von Manger or the “Dinner for Wanne”, a parody of the famous sketch “Dinner for one”.

industrial impressions

Our Field Trip was in Crange, a former district of Wanne-Eickel and now a part of Herne. Crange is very famous because it's the location of the famous “Cranger Kirmes”, which is the largest fair in NRW and the second largest in Germany behind the Oktoberfest in Munich.

Gate of Crange ("Cranger Tor")

The field trip was held on the meadows, where the fair is held each year. Past, there was a coal mine. The mine “Unser Fritz” was the largest in Herne.

3) List of Species

4) Pictures

 Alopecurus pratensis

Arenatherum elatius 

 Barbarea vulgaris

 Cardamine pratensis

 Carex hirta

Cerastium holosteoides

 Crategus monogyna
 Dauctus carota

 Equisetum arvense

 Fallopia japonica

Festuca ovinia 

Fraxinus excelsior

 Geranium molle 

Lamium album

Lamium purpureum 

Ribes aureum 

Rubus armeniacum 

Saxifraga tridactylites

Scleranthus polycarpus 

 Sedum acre

 Sisymbrium officinale

 Solidago gigantea

Stellaria media 

 Trifolium dubium

Veronica serpyllifolia 

Viburnum lantana 

Vicia sativa ssp. angustifolia

Donnerstag, 9. Mai 2013

Plant of the Day (May 9th, 2013) - Carex morrowii BOOT.

Todays's „Plant of the Day“ is Carex morrowii Boot. from the Cyperaceae family. In German, this sedge is known as “Japan-Segge”. In the English language, the species is known as “Variegated Sedge”. In Japan, the species is known as Kansuge
C. morrowii - habitus

1) Description

It's a perennial plant, which can reach a maximum height between 20 and 40 centimeters. The species grow in dense thickets. The long stalks are triangular, what is typical for plants of the Genus Carex. However, in contrast to other sedges, the stalks of C. morrowii aren't so sharp edged and very smooth.

C. morrowii - leaf (note the many leaf-veins and the keel)

The leaves are arranged in small bundles. Their leaf-blade is between 5 and 10 millimeters broad and has a deep-green color. In some cases, there are white stripes along the edges. This stripes are typical for the breed “Variegata”. The surface is thick and stiff, while the margin is very rough because of tiny spikes. There are also many leaf-veins and a pronounced keel at the center. Bracts are very short and become brown and fibrous towards the top.

 C. morrowii - bract

The rhizomes are short, but together, they form a thick tangle.

 C. morrowii - male ear with stamens

C. morrowii belongs to the Heterostachyae, so we have male and female ears. Specifically, there are one male ear at the end of each stalk and between 3 and 5 female ears along each stalk. Male ears are between 2 and 4 centimeters long and nearly narrow. They have a brown color and long, hanging stames.

C. morrowii - female ear with utricles

Female ears are located at the end of erected penduncles. They have a yellowish green color and extend obliquely. Each female flower has three white styli. Another, interesting feature are the recurved beaks of the utricles. “Flowering time” is between April and May. 

C. morrowii - closer look; you can see the thee, white stylie
of each utricle

 2) Distribution

C. morrowii is native to Japan. It grows in mountainous woods on the isles of Honshu, Shikoku and Kyushu (more common on the pacific side). It prefers fresh and shady places. However, the plant is also a very popular ornamental plant. Especially the breed “Variegata” with its white stripes is very popular. So, C. morrowii can also be found in other parts of the world like Europe or North America. In the most cases, these are garden plants but sometimes, a plant also starts to grow wild.