Taisha starts off this week's photographs with this write-up:
Today's photograph is of the moss, Dendroligotrichum dendroides. This image was contributed by Felipe Osorio-Zúñiga (aka Efe@Flickr), who shared it via the Botany Photo of the Day Flickr Pool. Thank you Felipe!
Dendroligotrichum dendroides is a "giant" moss distributed in South America (Chile and Argentina) the Juan Fernandez Islands and New Zealand. This species is typically found growing in temperate forests ranging in elevation from lowland to mountainsides. The gametophyte has a dendroid habit and resembles a miniature tree (which is clearly shown in today's photo). It is rightly termed a giant moss, as it has been reported to grow up to 40cm in height as a self-supporting plant! Few bryophytes can reach this self-supporting stature, with another notable exception being Dawsonia superba (recorded to reach up to 80cm). Do note that the stems of a number of moss species can extend beyond 40cm, but these are not self-supporting. Instead, these grow as creeping, prostrate, epiphytic, or aquatic plants.
The ability for Dendroligotrichum dendroides to stand at its considerable height is attributed particularly to its dense cortex (with contributions from its stem growth form). The cortex of Dendroligotrichum dendroides is made up of elongated cells with thickened walls that are collectively called the sterome. The sterome of this giant moss is measured to have stiffness of a similar magnitude to the stiffness of wood in trees. The growth form of this species is also similar to the mechanical design of large-bodied trees, where the stem of the moss tapers toward the apex. This gives the stem rigidity at the base and flexibility at the apex (see: Frenze, et al. (2011). Stem biomechanics of the giant moss Dendroligotrichum dendroides s.l. and its significance for growth form diversity in mosses. Journal of Byology 33(3):229-236).