Order Thuidiales

This group, which some times ago was contained in the Hypnales, consists, as the Hypnales, of pleurocarpous mosses. It is a collateral line of the pleurocarpous development, which branched off of the big Hypnales-line. The plants of this order are often strongly branched and regularly simply or multiple pinnate. This is why many species are rather decorative.

The leaves originally have long and thin cells. In the end the cells are short oblong or round because of the weak length stretching. The plants are often heterophyllous (i.e. the leaves e.g. on stems and branches differ). The cells are often papillous. Many species have paraphyllia - small green outgrowths in form of branched, slit or subulate cell filaments between the leaves, which probably improve capillarity.

Families are Fabroniaceae, Pterigynandraceae, Leskeaceae, Anomodontaceae, Thuidiaceae and Helodiaceae.

Fabroniaceae (incl. Myriniaceae)

typical Fabroniaceae

A typical Fabronaceae (Genus Anacamptodon).

This family consisting of 16 genera can be found mostly in the warmer parts of Africa and America. In Europe there are 6 species in 5 genera. The species are in most cases epiphytic, and form tender turfs of creeping plants. The drawing on the right shows a typical such turf (Genus Anacamptodon).

In most cases the leaves have a simple midrib. The cells of the leaves are rhombic or oval, often elongate. Only the alar cells are quadratic.

Pterigynandraceae (incl. Theliaceae)

typical Pterigynandracee

A typical Pterigynandraceae (Genus Myurella).

The members of this family can in most cases simply be recognized by their leaves: The leaves are rounded or short ovoid and normally very hollow. They are imbricate, so that the plants look like small, round worms.

Often the edges of the leaves are denticulate. There is no midrib, or it is very short, or short and bifurcate. The cells have papillas on the upper side.

In total the family consists of 4 genera, of which the monotypical genus Pterigynandrum is often put into its own family, whereas the other 3 genera are put into a family Theliaceae. None of the species is frequent in central Europe.

A rather typical representant is Myurella tenerrima. The drawing on the right shows a Myurella-species too.

Leskeaceae

typical Leskeacee

Leskea spec.

The members of this family are in most cases easy to recognize under the microscope by the shape of their leaves and their leaf cells. Nevertheless there are nearly no characteristics shared between all species. In most cases the plants are (regularly or irregularly) branched, and small or medium sized.

The leaves are oval until lanceolate. The have a more or less strong midrib, which sometimes ends in the tip of the leaf, sometimes before the tip. The cells of the blade are often rhombic or rectangular, sometimes prosenchymatic. The may be smooth or papillous. But in the latter case they are not very papillous. And if they are prosenchymatic, they are not as long and thin as it is the case in the Hypnales.

The capsules are erect and symmetric. Paraphyllia are, if they exist, not very numerous. They are smooth and not branched.

This family can be found mostly in regions with moderate climate. It consists of 10 genera, of which 6 can be found in Europe. But the division into genera is matter of discussion.

A typical member is the name giving genus Leskea, which can be seen on the drawing on the right too.

Thuidiaceae

typical Thuidiacee

Thuidium tamariscinum

The Thuidiaceae are typical members of the order: They consist of more or less regularly, double or triple pinnate mosses. They are often very decorative. Some species are even collected and are traded as decoration.

The broad triangular leaves consist of rounded cells. The cells have, depending on the species, one or several papilla - at least at the tip of the leaf and in the basal angles. Stem leaves and branch leaves are clearly distinguished. The stem leaves are bigger, broader and more clearly plicate.

Paraphyllia exist and are numerous. Often they are ramified and papillous.

The capsules are arcuate.

The most frequent european species is Thuidium tamariscinum, which can be seen on the drawing on the right too.

Anomodontaceae

This group of mosses is sometimes put into its own family, sometimes into the Thuidiaceae, sometimes even into the Leskeaceae. Recently the family is put into the Neckerales.

The plants have rounded, very papillous cells. Paraphyllia don't exist. They are mostly irregularly branched robust mosses.

The capsules are erect, cylindrical and straight.

A rather typical member is Anomodon viticulosus.

Helodiaceae

This group too is sometimes put into its own family, sometimes into the Thuidiaceae. I don't know much about it. It is a smaller family of more or less regularly simply pinnate, medium sized, soft, yellowish-green mosses, which grow in moors, bogs or swamps. In Europe the family is only represented by the species Helodium blandowii, which can be found above all in Scandianvia, and seems to be nearly extinct in central Europe.

The hollow leaves are broad lanceolate, with a midrib, which reaches the tip of the leaf. The cells are elongated rhombic until prosenchymatic. They are smooth or sometimes with one papilla per cell.

by Michael Becker, 6/2000. Translated: 4/2002.
Last modification: 2/2002.