The Mat Rushes or Iron grasses are in Family Asparagaceae > subfamily Lomandroideae.
They have been (and still are in places) seen in Xanthorrhoeaceae, Liliaceae or Lomandraceae.
The 51 species are all native to Australia.

They are perennial herbs that may form clumps or tussocks.
There are rhizomes (underground stems) with fibrous roots.
Overlapping leaf sheaths may form a short above ground stem.

The erect or arching, soft or firm strap-like leaves are in 2 ranks (distichous).
They are a few cms up to 100 cm long and 1 to around 15 mm wide.
They can be flat, have the edges rolled under or be cylindrical.
The tip can be rounded, flat or have 1 to 3 large or small teeth.
The green, blue-green or purple leaves may occasionally have some hairs.

The base of the leaf widens into a sheath sometimes with lobes or auricles at the top.
The sheath edges can be smooth or frayed into thin fibres.
The margins may be white or a purplish-brown.

The inflorescences are on a leafless stalk or scape.
The scape is often hidden among the leaves or only extends a few cms above them.
Inflorescences can be a spike, be branched or consist of dense heads.
The long or short, erect or spreading branches can be mainly opposite, alternate or in whorls.
Along the banches the flowers can be solitary or in sparse to dense clusters.

All species have some bracts associated with the inflorescences but their number, size and features vary with the
    species and are important in differentiating them.
Cluster bracts, at the base of the inflorescence and any branches are often the most prominent.
There are opposite and overlapping outer and inner bracts enclosing the flower bud.
The outer bract is at the base of the pedicel and the inner bract or bracteole is on it.
When there is no pedicel they are both immedictely under the flower.
There may also be intermediary bracts between the cluster bract and the others and sometimes not all are present.

The flowers have no stalk or pedicel or one up to around 1 cm long.
Often only a few mms long the female flowers are usually larger than the males.
The perianth is in 2 whorls with 3 roughly similar tepals in each.
Tepals can be free, partly to fully fused or joined at the base by the stamen filaments.
The white, cream, yellow, greenish or purple flowers may remain almost closed or open fully.
Male and female flowers are on separate plants.

Male flowers have 6 stamens, with filaments of the same or different lengths in 1 or 2 whorls.
The outer 3 are inserted on the top of the perianth tube or the top of the pedicel/stem.
The inner 3 are on the tube just, or some distance below the outer ones.
Males have a rudimentary ovary.

Female flowers have a superior ovary that is sometimes on a short stalk.
It can be spherical, cylindrical or 3-angled and has 3 locules each with 1 ovule.
There may be a single short style or it can be split into 3 and there are 3 stigma lobes.
There are 6 tiny infertile staminodes.

The spherical cylindrical or 3-angled loculicidal capsules have a smooth or wrinkled surface.
Each of the 3 chambers has 1 orange, reddish or brown seed.