Donnerstag, 31. Januar 2013

Species of the Day - Evernia prunastri (L.) Ach.

After a longer break, which I use to give the article about the very interesting genus of Cladonia a little bit more attention, it's now time for a new article. However, this will also be about a lichen, because it's still winter and this means lichen time. This new lichen is Evernia prunastri (L.) Ach. from the Parmeliaceae family. In German, this species is known as “Flaumenflechte” or “Eichenmoos”. In English, the species' name is “Oakmoss “, what is the literally translation of the German name “Eichenmoos”.

E. prunastri - on a tree

Typical for this species is the bushy and foliose Thallus, which can reach a length between 3 and 4 centimeters. The primary Thallus grows in a small rosette, from which several branches are emanating (this is the secondary Thallus). 

 E. prunastri  - this is a younger individual. The Soralia 
aren't strongly branced yet  

These branches are so called Soralia (similar to C. fimbriata in my previous post); vegetative shoots, which grow through holes on the rough surface of the primary Thallus. These Soralia are repeatedly branched dichotomously and resemble to an antler, what gives the lichen a very special habitus. The number of branches may vary from only a few to numerous. In the last case, the Sorals may form a dense web.

E. prunastri - closer look at the thallus; you can also
see the dichotomy of the soralia

The color of both Thalli varies from a grey green to a pale or yellowish green. Sometimes, a grey color is also possible.

Apothecia are rare at E. prunastri, because the major part of propagation happens vegetative over Soredia. These are small clusters of hyphae and algae, which are located on the ridge or at the margin of the Sorals and be delivered from here. They are normally brighter than the rest of the Thallus but can also have the same color, which makes it very difficult to see them with eye
If Apothecia are present, they are cup-shaped and can be found at the margin of the Thallus. Their inner surface has a dark-brown to rusty red color, while the outer surface has the same color as the rest of the Thallus.

 E. prunastri - on a tree with many other lichens like
Flavoparmelia caperata

E. prunastri is widespread circumpolar in the temperate regions of the Northern and Southern hemisphere. However, some populations have also be found in North Africa. It prefers a neutral to slightly acid substrate and is an epiphyte, which grows on trees. So, it can be found mainly on the barks of broadleaved trees like the oak (Quercus robur, what is also the reason for the name “Oakmoss”). But E. prunastri can also grow on other broadleaved trees (like beech) and even on the bark of some conifers like pines.

E. prunastri - this is an older individual. The soralia are
much longer and more highly branched

This lichen is more common in the lowlands but can also be found in mountainous regions until 1750 meters. It favors a moist and clean air. In dryer regions, the generative propagation through Apothecia and spores is more frequently. This suggest, that the Soralia grow better in a more humid air.

Due the high amount of fragrances, E. prunastri has become a Basenote in the perfume production. The distilled fragrance is known as “mouse de chenne”. However, these ingredients can also cause an allergic reaction to the skin, and therefore the use isn't so common today.

Dienstag, 15. Januar 2013

The Genus "Cladonia"

Mosses aren't the only organisms, which can best be examined during the winter, when most of the higher plants are in hibernation. Lichens can also be viewed at this time particularly well and so I want to write about a lichen this time. Specifically, it isn't one species but three from the Genus Cladonia. These three species are Cladonia furcata (Huds.) Schrat.; Cladonia foliacea (Huds.) Wild. and last but not least Cladonia fimbriata (L.) Fr.

As is said it before, all of these species belong to the Genus Cladonia, which belongs to the Cladoniaceae family. The Cladoniaceae are part of the order Lecanorales. There are approximately 350 different species within the Genus Cladonia. The habitus of these species can vary greatly, because they are rich in shape.

1) Cladonia furcata (Huds.) Schrat.

The first lichen, I want to show you is Cladonia furcata. In German, this species is known as “Gabel-Flecht” (Fork-Lichen) or “Gabel-Säulenflechte”. Unfortunately, I haven't found a common English name.

C. furcata - habitus

This species have to different Thalli (“bodies”): a primary Thallus and a secondary Thallus. The primary Thallus of this lichen is flattened and have a leaf-like shape with a lobbed margin. It's about 4 millimeters long and 3 millimeters wide and lies directly on the substrate

C. furcata - habitus

On this primary Thallus, the secondary Thallus grows. In Botany, the secondary Thallus is called Podetia (Sing.: Podetium) and is typical for many lichens of the Genus Cladonia. It has the shape of small, upright growing branches. In the case of C. furcata, the podetia are richly branched, what gives them an fork-like habitus. This is also the reason for the name of the species. All in all, the Lichen have a foliose or spongy habitus, which reminds a little bit to a small coral.

C. furcata - Podetia

In both cases, the Thalli can vary greatly in color, what also depends a little bit on the substrate on which the lichen grows. The color may range from a deep, dark green to a silver-gray or brown.

Like the most Lichens, C. furcata also has cup-like Apothecia (Sing. Apothecium) for reproduction. These are the fruit bodies of the lichen, where the Asci (Sing. Ascus), the tubular spore-bearing cells are located. With C. furcata, the Apothecia are at the end of the branches (podetia). They have a dark-brown color.

C. furcata - grows often between mosses

C. furcata is distributed worldwide and can be found on every continent (except Antarctica). It grows on different substrates and can be found mostly between mosses but also on the pure soil. In some cases, it also grows on rotten wood.

It should also be noted that some ingredients of C. furcata may be able to kill cancer cells. Especially at leukemia cells, this effect was observed. Because of this, the species has some value for cancer researchers.

2) Cladonia foliacea (Huds.) Wild./ Cladonia convoluta (Lam.) Anders.

The second Lichen is Cladonia foliacea (Huds.) Wild. In German, this plant is known as “Blättrige Cladonie”. Again, I didn't found an English name but the Latin name means something like “folios Cladonia”.

C. fasciola - beneath a bush

Please note: The Taxon Cladonia foliaceae is very similar to another Taxon named Cladonia convoluta (Lam.) Anders. The boundaries between these to Taxa are blurred and together, they form a single, taxonomical complex. For simplicity, I will remain with the name “Cladonia foliaceae” but keep this fact in mind.

C. furcata - a dense tufe on a slope

The Thallus of this lichen grows flattened on the soil and reaches heights between 1 and 3 centimeters. However, it's not uncommon, when several lichens overlap and form a dense turf. The Thallus is deeply lobbed and divided into several, leaf-like structures. Their dorsal site have an olive-green color, while the ventral side is yellowish or white. In many cases, however, the “leaves” are folded and so, the ventral side points up.

C. furcata - Thallus. Yoe can see the bright, ventral site

In contrast to other lichens from the Genus Cladonia, C. foliacea have only short and inconspicuous Podetia and even Apothecia are rare to find, because the species propagates vegetative primary.

C. fasciola - Closer look

The complex of C. convoluta / C. foliacea is native to Europe but some sub-species can also be found in the United States, Siberia, the Middle East and even Australia (almost all C. foliacea). The main areal of C. foliacea is Scandinavia, while the main areal of C. convoluta is Spain. In between, the transition between these two species is blurred.

The species grows in a temperate climate and likes bight places. So, it can be found on rocky slopes, clearings and dry meadows. It prefers a nutrient-poor soil.

3) Cladonia fimbriata (L.) Fr.

The last lichen, which I want to show you, is C. fimbriata. The German name of this species is “Trompetenflechte”, what means “Trumpet lichen” in English. The Latin suffix “fimbriata” means “fringed”.

C. fimbriata - habitus

As with the Thallus of C. furcata, the Thallus of C. fimbriata is subdivided into a primary and a secondary thallus. The primary Thallus is between 6 and 4 millimeters long and consists of small, leaf-like lobes, which lie flat on the substrate.

C. fimbriata - habitus(here you can see the trumpet-shaped

The primary Thallus is very inconspicuous in contrast of the Podetia of the secondary Thallus. These are between 2 and 3 centimeters long and are about 1 millimeter in diameter. They have cup-like tips (4 millimeters in diameter), which give the podetia the look of a trumpet. This is, of course, also the reason for the name “trumpet lichen”.

C. fimbriata - in a wood. Note the long Podetia
(Photo taken by Christopher Schwerdt)

Both Thalli have a gray-green to slight green color and a rough, surface, which is broken in many places. In Lichenology, these cracks are called Sorals (Sing.: Soral) and serve the vegetative propagation. Through them, a lichen can give off small packages (so called Soredia) of hyphae and algae and multiply so without fertilization.

C. fimbriata - primary thallus

The small Apothecia are located within the cups and have a brown color. However, they are very uncommon. because the lichen reproduce mostly through the Soredia.

C. fimbriata can be found in the temperate regions of the northern and southern Hemisphere. It grows on shady places and sandy soils. Some grew places are woods, tree trunks, mosses and also rocks. The species is very common in Europe and easily recognized by its trumpet-shaped podetia.

4) Epiologue

So, I hope, that I was able to give you a basic overview about the Genus Cladonia and three of its species. In the next weeks, I will also take a closer look at the biology of lichens, what is also very interesting. This weekend, I will participate in a field trip about lichens and mosses at the Ruhr-University of Bochum; organized by the “Botanischer Verein Bochum” . Maybe I will able to show you some new species after that.

Please note: The third  picture of Cladonia fimbriata were taken by Christopher Schwerdt. I have his permission to use these pictures in my blog. Please also visit his homepage

Dienstag, 8. Januar 2013

Plant of the the Day (January 8th, 2013) - Rhytidiadelphus squarrosus (Hedw.) Werst.

The “Bryoweeks” continue with another moss, which is also very common. Gardeners maybe know and hate it. The species, I'm talking about is Rhytidadelphus squarrosus (Hedw.) Warnst., a moss from the Hylocomiaceae. In English, the species is known as “springy turf moss” or “goose neck moss”. In German, it has some curious names like “Sparriger Runzelpeter” (bulky, wrinkled Peter) or “Sparriger Runzelbruder” (bulky, wrinkled brother) but the most common name is “Sparriges Kranzmoos” (bulky wreath-moss).

Rhytidiadelphus squarrosus - habitus; you can als see
the characteristic "wreath".

The Gametophyte grows in well-branched shoots. The upright growing branches have a maximum height between 10 and 15 centimeters (4 to 5.8 inches). It grows in dense turfs and can displace other plants like grasses easily.

 R. squarrosus - foliage

The reason is the rapid growth of the shoots. R. squarrosus only grows at the tip, while older parts perish but remain at the shoot. Thereby, the species can form quickly large cushions. The effect is similar to the peat mosses (Genus Sphagnum), what is also the reason for the suffix “Squarrosus”, which means “like Sphagnum”.

 R. squarrosus - foliage

The leaves of the living parts have a very unique shape. They are between 2 and 3 millimeters long and have a bright green to yellowish green color. They are spade-shaped and have a very broad leaf-base, which covers the stem completely. Thereby, the stem is only visible through the leaves. The leaves of the lower parts of the branches lie flat on the stem, what gives the shoot a bulky look. This is also the reason for the German name “Sparrig”, what means something like “bulky”.

 R. squarrosus - here, you can see leave, which lie flat
on the stem

However, the leaves of the upper regions are also spade-shaped but they are folded from the middle and run in a long, narrow tip. This tip is almost right angles from the stem, what gives the shoots in the upper regions a star- or wreath-like habitus. This look is very characteristic for R. squarrosus and responsible for the name “wreath-moss”.

  R. squarrosus - here, you can see leaves with the 
protuding tip. You can also see the stem through
the leaf base 

The older parts of the plant have a brownish color and have white leaves, because their dead leaves (same shape like the leaves of the living parts) haven't any chlorophyll.

 R. squarrosus - picture shows a dead part of the plant
with its clorophyll-free leaves

The Sporophyte is very inconspicuous, with a very short seta and small, oval capsules, which are between 1 and 2 millimeters long. In most cases, the Sporphyte lacks completely and the plants reproduce asexual by offshoots.

 R. squarrosus - the leaves at the stemm (centre) lie flat on the
stem while the leaves of the stem are protruding

R. squarrosus is native to the whole northern hemisphere and a Neophyte in the southern hemisphere. It's nearly ubiquitous and can be found on pastures, meadows and in parks and gardens. This is due of its high adaptability, because R. squarrosus can grow on nearly all soils from calcareous to acid.

Because of its high adaptability and fast growin, R. squarrosus is very unpopular for gardeners, because it can overgrow other small plants like grass easily. This is also a problem on some golf courses, where the species grows on the Fairway.

Freitag, 4. Januar 2013

Plant of the Day (January 4th, 2013) - Hypnum cupressiforme Hedw. s. str.

Happy New Year, everybody.

Winter is a good time to write and post some Articles about Lichen and Mosses, because these plants are not affected directly by the harsh climate outside and can also be found them during the cold months abundantly. So, after my Article about Tortula ruralis and Grimmia pulvinata it's time for another article about a moss. This species is Hypnum cupressiforme Hedw. s. str. from the Hypnaceae family. In German, this species is known as “Zypressen-Schlafmoos” while common English names are “cypress-leafed moss” or simply “Hypnum”

H. cupressiforme  - on a bark

The branches of the Gametophyte are about 10 centimeters long with about 1 centimeter long sub-branches Apart from this, the Gametophyte is very rich in forms. Sometimes, it grows in lush and dense branched turfs, sometimes the branches are growing parallel to each other. The habitus also depends on the growing place. Plants on rocks or bollards normally grow in dense turfs, while on barks, H. cupressiforme grows in parallel hanging filaments. It's also possible, than one plant grows in different forms at the same time (e. g. while hanging at a bark and growing on a branch of a tree at the same time).

H. cupressiforme - sporophyte

The leaflets are between one and two millimeters long. They are curved and folded at their apex, what results in a sharp, narrow tip. All leaflets have two leaf-veins but in contrast to other mosses, these leaf veins are very short. Their margin is smooth throughout.

Leaves and branches of H. cupressiforme can also vary greatly in color, what makes an determination for beginners even more difficult. The spectrum ranges from a yellowish green to a grass green or a dark green. The color depends on humidity, environment and substrate.

H. cupressiforme  - on a wall

The Seta of the Sporophyte is between 1 and 3 centimeters long. The capsules with the spores have a brown to reddish brown colour. They are often nodding and have a short but distinct beak. The ripening of the spores is between Winter and Spring.

H. cupressiforme  - a closer look on the sporophyte, where
you can see more details: C = Capsule; B = Beak; S = Seta

H. cupressiforme is a cosmopolitan and one of the worlds most common mosses. It grows on barks, cobblestones, snags, walls and even on the pure soil between sea level and nearly 3.500 meters. It's also indifferent towards the soil and grows on acid and basic soils equally.

In former times, some people believe, that the branches of the Gametophyte have a soporific effect and so, H. cupressiforme was used to cure insomnia. For this purpose, plants were dried and stuffed into pillows instead of downs, what is also the reason for the name of the genus (“Hypnum” is Latin for “Sleep”).