Juncaginaceae is the Arrow-grass Family.
There are 4 genera (Triglochin, Lilaea,Tetroncium and Cycnogeton) and about 25 species.
They are not grasses but herbs that live in aquatic or wet areas worldwide.
They have linear leaves and small flower with parts in 3’s.
Australia has about 12 native species of Triglochin.
T. striatum is also known as streaked arrow or three-rib arrow-grass.
They are perennial herbs up to 30 or 35 cm high living in permanently wet areas.
They are anchored by extensive rhizomes (underground stems).
The leaves, in small clumps, arise along the rhizome.
The linear leaves are only a few mms wide with 3 ribs running down them.
The bases are sheathed and when they die fibrous strands remain at the base of the plant.
Inflorescences, usually shorter than the leaves, are a spike-like stem with flowers on the upper part.
The 2 mm long, bisexual flowers are on short stalks.
The perianth has 6 tepals in 2 whorls of 3 that fall off easily.
The gynoecium has 3 fertile and 3 sterile carpels fused to various degrees.
Each fertile carpel has 1 ovule and 1 stigma.
There are 6 stamens.
The 2 mm long fruits are globular.
When mature the carpels separate.