Freitag, 28. Juni 2013

Plant of the Day - Asplenium scolopendrium L.

After a long time, I want to present you a new fern in my blog. This fern is Asplenium scolopendrium L. from the Aspleniaceae family. The German name for this fern is “Hirschzungenfarn” (Deer-tongue fern) or simply “Hirschzunge” (Deer-tongue). In English, the species is known as hart's-tongue fern.

1) Description

A. scolopendrium - habitus

A. scolopendrium is smaller fern, which can reach heights between 10 and 100 centimeters (3.9 to 39.4 inches) A plant consists of several fronds, which grow in a dense, funnel-shaped stock. Unlike the fronds of other ferns like Dryopteris filix-mas or Athyrium filix-feminia, the fronds of A. scolopendirum aren't pinnate but tongue-shaped and have a slightly lobbed margin. In addition, they are heart-shaped at the base with distinctive ears

 A. scolopendrium - frond (you can also see
the distinctive, heart-shaped leaf-base with its ears

Young fronds have a bright-green colour but they become dark-green with age. Another interesting feature are the branched leaf-veins, which runs from the central rachys (the rip in the center) to the margin. Botanists suspect, that these veins are a more primitive character, which classifies A. scolopendrium as a very basal taxon of ferns.

A. scolopendrium - the stalks of the fronds with the scales

The Sori (the sporangia-clusters with the spores) are located on the ventral side of the fronds. They have a linear shape and are arranged in parallel lines, which are oblique to the rachys. Unlike other ferns like Blechnum spicant, there is no difference between fertile and sterile fronds; they look the same. The spores become ripe between late summer and early autumn.

A. scolopendrium - frond

As with other ferns, there are many hybrids and polyploid subspecies of A. scolopendrium, which may differ in morphology. For example, there is a popular garden form of this fern, which have a stronger curled margin.

3) Habitat and Distribution

A. scolopendrium -in a forest

A. spcolopendrium is native to the temperate realms of the Northern Hemisphere and can be found in the oceanic areas of Europe, North America and Asia. However, it's not widespread and can be found selective in only a few regions. Thereby, the species is protected by law in some countries (like Germany).

A. scolopendrium - in a shaft

The fern prefers fresh, shady places on north exposed slopes. So, it can be found in the undergrowth of gorge forest between maple and oak trees. But in some cases, the plant can also be found in cities on ruderal wasteland, at walls and in the shafts of basements. This is probably, when the deposited rock is calcareous.

Donnerstag, 20. Juni 2013

Animal of the Day (June 20th, 2013) - Buffo calamita LAURENTI

I recently took part in a field trip to the “Grube 7”, an old limestone quarry in Haan-Gruiten. This was a very interesting field trip, whose report I will post next week. However, as a little sneak peak, I want to present you one of the most interesting species, we had found during the field trip.

This isn't a plant but an amphibian: Buffo calamita LAURENTI from the Bufonidae family. In English, this species is known as “Natterjack toad”. In German, we call it “Kreuzkröte” (cross toad).

1) Description

B. calamtia is a small toad, which can reach length between 5 and 7 (sometimes to 8) centimeters. In contrast to other Amphibians, female toads aren't much larger than male toads. The head is wider than long and rounded. The eyes of B. calamita has a black, horizontal pupil, while the iris has a lemon-green color.

B. calamita - habitus

Unusual for a toad, the hind legs of B. calamita are very short. Because of that, the species is not able to make long jumps like other toads. It runs rather over the floor like a mouse.

  B. calamita - front view

The back-color of the Natterjack toad is a brown to olive-green pattern on a light background. The typical toad warts have a reddish to red-brown color. However, the unique and most significant feature of B. calamita is the yellow (or white) stripe, which runs from the forehead to the base of the tail. Unlike other toads or frogs, the skin on the back is very dry and not mucous. The belly has a white color with some darker spots. Some male toads also have a dark-violet spot on their throat.

 B. calamita - back view; you can see the yellow stripe
on the back

The vocal sac on the throat has a large volume. As a result, B. calamita can blow it wide and has a very loud voice despite its small size. This voice sound like a dry “arr arr arr” and is heard in a radius of nearly 2 kilometers (!).

2) Modus vivendi & reproduction

The Natterjack toad is a pioneer and prefers warm, open places with only loose vegetation. Such places are e. g. natural riversides or lake sides, where the flood prevents a denser vegetation. In such areas, the toad live outside the water, where it hunts insects, worms or snails. 

B. calamita - face; you can see the pupil and the iris 

It only goes into the water for mating. The male toad goes into a suitable stretch of water (like a puddle or a pound), where it starts to shout with its vocal sacs in order to attract female toads. After mating, the female toads lay a long spawning into the water, which contains nearly 4000 eggs. 

Main breeding season is between April and May.
Shallow ponds like this are the ideal habitat for B. calamita

After about 4 days, the tadpoles hatch. These tadpoles live in large swarms in the warmer regions of the water. They have a black color and only need about four weeks to grow into a young toads. This is important, because their birth places can dry out very fast. On the other side, there are not many predators (like fishes or other Amphibians) in puddles and so, nearly all of the tadpoles survive.

There were also some tadpoles in the pond (red circles)

3) Habitat and Distribution

B. calamita is native to Western-Europe, Middle-Europe and parts of Easter Europe. It can only be found north the alps and not in Southern Europe or the Balkans. As I said it before, the species is a pioneer and can be found on wastelands with loose vegetation. These are salt marshes, riversides or brownfield lands which are seasonal flooded.

However, such places become rare in Middle Europe and as a result, the Natterjack Toad is threatened by loosing its breeding places and habitats. However, there are some man-made habitats for B. calamita, which are perfect alternative habitats. These are e. g. ruderal wastelands, former quarries or even former training areas of tanks (these heavy vehicles compress the soil and create ideal puddles for the toad without high vegetation).

Today, the Natterjack toad is protected strictly by law. Its new, artificial habitats (like the “Grube 7” are obtained by conservationists.

Please note: These animal was shown to me by qualified conservationists. It wasn't in danger and released after the presentation.

Donnerstag, 6. Juni 2013

Plant of the Day (6th June, 2013) - Centaurea montana L. (or Cyanus montanus)

Today’s “Plant of the Day” is a real beauty: Centraurea montana L. from the Asteraceae (or Compositae) family. In German, the species is known as “Berg-Flockenblume”. In English, the species has different names like “mountain cornflower”, “Bachelor's button” or “mountain knapweed”.

Please note: According to current researches, the species belongs to the new genus Cyanus (along with Centaurea cyanus L. and Centaurea triumfetti (Gugler) Dorstal). So, its new name is Cyanus montanus. However, in most books the species still has its old name, so I also will use it in this post.

1) Description

C. montana - habitus

C. montana is a perennial plant, which can reach heights between 30 and 60 centimeters (12 to 26.3 inches). The whole plant is covered with small, felty hairs. The leaves are lanceolate to egg-shaped and have a smooth margin, which isn't serrated or deeply lobed. However, there is a white line along the whole margin.

C. montana  - foliage

The leaf-bases are decurrent on the stalk. Thus there is no petiole and the leaves sitting directly at the stalk. Leaves have a dark-green color. In addition, young plants are dense covered by the hairs, so they shimmer silvery. However, foliage leaves get bald with age and are more green than silvery.

C. montana - invulucrum (note the black fringes of the bracts)

A distinctive feature of C. montana are the bracts, which are covering the inflorescence. If you remember to my Article about the Asteraceae, you know that this hull of bracts is called Invulucrum. The small bracts are triangular and overlap each other like tiles. They have small fringes at the edge, which have a black color.

C. montana - inflorescence

During late spring, the Invulucrum opens and releases the beautiful inflorescence. Like all Asteraceae, the inflorescence of C. montana heads, which consists of many single flowers. These heads are between 3 and 5 centimeters (1.3 to 5 inches) in diameter.

C. montana - inflorescence

As member of the Carduoideae, the heads of C. montana consists only of disc flowers but there are two kinds of them. The disc flowers in the center have a violet color and are smaller than the peripheral disc flowers, which have a deeper purple color. These flowers are also elongated and frayed and fleeced at the top. Flowering time is between May and August.

C. montana - stalk with hairs

In some cases, C. montana is confused with Centaurea triumfetti,a closely related species. The best way to distinguish these two species is to look at the fringes of the bracts. The fringes of C. triumfetti are much longer and more brown than black. In addition, the leaves of C. triumfetti are more hairy, because they don't getting bald. However, a clear distinction isn't always possible. Especially in gardens, there are many hybrids between these two species.

2) Ecology & Distribution

Originally, C. montana is endemic to the mountains of Southern and Middle Europe. As the name “montana” suggests, it's a plant of mountainous regions and grows on rocky slopes, in ravine forests and mountain forests and on high meadows, where it prefers nutrient-rich places.

However, C. montana is also an ornamental plant and popular with Gardeners, because of its flowers and small claims towards its growing places. It can grow in light and semi-shadow and as a mountain plant, it has no differences with hard, rocky soil. This circumstances have helped, that the plant has also become native outside of its original areal. For example, C. montana can be found in England, Scandinavia and even in North America.