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.

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