Monday, December 3, 2012

Hypnum imponens - the Brocade Moss

As i was hiking around the park trails the other day, i picked up this piece of birch bark...

i loved the little moss poking through the crack in the i looked closer at it, i noticed that there were actually two species, Hypnum imponens and Leucobryum glaucum, both of which are very common on the ground. It got me to thinking about how they came to be in that little piece of bark, and i came to the conclusion that the bark was growing close to the ground and as the tree was dying (or dead) the mosses grew up from the ground and through the bark.
   i've been noticing Hypnum imponens a lot over the past seems to glow at the trail edges, maybe that's because there's so little green in the woods these days and one is less distracted. Commonly called 'Brocade moss' i think due to its usually neat, embroidered look. it can form extensive mats on old logs and humusy ground and likes it a little damp. This is what it commonly looks like:

it often has a very characteristic orange-brown color and a very neat arrangement of branches along the stem called pinnate (like a feather).

Like many in the Hypnum genus, it has very curly leaves which you would see if you turned the branch looks smooth on top and somewhat bristly underneath (which are all the leaf tips curling under)

under side of branch tip

curved leaves - often called 'falcate-secund'
you can also see that it has no midrib or 'costa' to the leaf and something interesting is happening at the leaf base where it attaches to the stem. most of the cells in the main part of the leaf are quite long and linear...but the cells at the base are much shorter, even a little inflated. Those cells are called 'alar' cells and are often differentiated in many species of moss and are used as an aid in identification of closely related species.

so..closer up, these cells look like this:

in Hypnum imponens they are often distinctly colored orange-brown as well.
Look for this common species the next time you are out hiking!

next post, i'll take a closer look at the other species found in bark - Leucobryum glaucum

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