Gonocarpus tetragynus is an Australian herb in the watermilfoil family Haloragaceae native to eastern Australia. Common names include common raspwort. A widespread species particularly found in dry eucalyptus forests, scrubland, and heathland.

Description

White appraised hair covering the leaves and stem of Common Raspwort

The herb can grow erect or ascend to 15-30 cm (5.9-11.8 in) tall. The many wiry branching stems can be smooth or are weakly 4-ribbed.

Leaves A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...

are

decussate Decussation is used in biological contexts to describe a crossing (due to the shape of the Roman numeral for ten, an uppercase 'X' (), ). In Latin anatomical terms, the form is used, e.g. . Similarly, the anatomical term chiasma is named aft ...

lanceolate The following is a list of terms which are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (a single leaf blade or lamina) or compound (with several leaflets). The edge of the leaf may be regular o ...

and range from 0.6-1.2 cm (0.2-0.5 in) long. The

leaf margins A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, ste ...

are thickened, irregularly toothed and recurved. The leaves are attached to petioles, 0.5-1 mm (0.020-0.039 in) long. The

bracts In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are usually different from foliage leaves. They may be smaller, larger, or of ...

are sessile, alternate, lanceolate, and range from 2-2.5 mm (0.079-0.098 in) long. The bracteoles are membranous, lanceolate to linear-lanceolate, 0.8-1.2 mm (0.031-0.047 in) long. Both the leaves and the stem are covered in white-appressed hairs, which gives a rough texture. Inflorescence of Gonocarpus tetragynus

The species is

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wide ...

. The

flowers A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...

are

bisexual Bisexuality is a romantic or sexual attraction or behavior toward both males and females, or to more than one gender. It may also be defined to include romantic or sexual attraction to people regardless of their sex or gender identity, whi ...

, but in the occasional individual, they become functionally female, after the abortion of the stamens and the petals. The flowering time ranges from Spring to Summer; as early as September and as late as February. The

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...

is a spike with tiny solitary flowers which are 1-3 mm (0.039-0.12 in) across. Like in other members of the Haloragaceae family, the flowers are divided into 4 whorls. The

sepals A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 The term ''sepalum'' was coined b ...

are deltoid and green, with a prominent basal callus. Petals range from green to red and are hooded and keeled. The herb has 8 stamens and an 8-ribbed

ovary The ovary is an organ in the female reproductive system that produces an ovum. When released, this travels down the fallopian tube into the uterus, where it may become fertilized by a sperm. There is an ovary () found on each side of the body. ...

. The

fruit In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particu ...

is a dry nut, a family characteristic. The herb develops a ridged, globular nut. It is 1-1.3 mm (0.039-0.051 in) long. The colour ranges from silver-grey to slate grey.

Taxonomy

Jacques Labillardière first formally described the species as G. tetragyna in 1805; as published in Novae Hollandiae Plantarum Specimen 1. Its variant, Gonocarpus tetragynus, would be the accepted name by 2005, according to the Australian Plant Census of the same year. Several other synonyms are known including Goniocarpus tetragynus, Haloragis gonocarpus, Haloragis tetragyna, Halorrhagis tetragyna, Gonocarpus tenellus, Haloragis rubra, Halorrhagis rubra.

Distribution and habitat

The species is widespread, in terrestrial Eastern Australia. It occurs in Queensland, New South Wales, ACT, Victoria, South Australia, and Tasmania. The herb can also be found in the Flinders and Clarke islands in the Bass Strait. While widespread it is particularly found in moist to dry soils in dry Eucalyptus forests, shrublands, and

heathlands A heath () is a shrubland habitat (ecology), habitat found mainly on free-draining infertile, acidic soils and characterised by open, low-growing woody vegetation. Moorland is generally related to high-ground heaths with—especially in Great B ...

. In Tasmania, it is commonly found on dry stony outcrops. Records of this species in other countries are based on miss identification of G. incanus, G. montanus, G. chinensis, and G. philippinensis.

Distinguishing from similar species

Gonocarpus tetragynus is similar in appearance to

Gonocarpus humilis ''Gonocarpus humilis'', commonly known as shade raspwort, is a small herb in the genus '' Gonocarpus'' of the family Haloragaceae. Shade raspwort is common along the eastern coast of Australia, and grows in moist and shaded locations. The leaves ...

. The two species can be distinguished by the former's lanceolate leaves, an even cover of white-appraised hairs and the flower’s 8 stamens.

Cultivation

Cultivation of the species is possible, but it is not widely grown.

References

{{Taxonbar, from=Q15604978 tetragynus Flora of Victoria (state) Flora of New South Wales Taxa named by Jacques Labillardière Flora of Queensland Flora of the Australian Capital Territory Flora of South Australia Flora of Tasmania