Sida acuta, the common wireweed, is a species of flowering plant in the mallow family, Malvaceae. It is believed to have originated in Central America, but today has a pantropical distribution and is considered a weed in some areas.[1]
In northern Australia, Sida acuta is considered an invasive species, and the beetle Calligrapha pantherina has been introduced as a biological control agent in an attempt to control the plant.[2]
Undershrub, with mucilaginous juice, aerial, erect, cylindrical, branched, solid, green.
Alternate, simple, lanceolate to linear, rarely ovate to oblong, obtuse at the base, acute at the apex, coarsely and remotely serrate; petiole much shorter than the blade; stipulate, stipules free-lateral, unequally paired at the node, reticulate venation.
Cymose
Small, axillary, 2–3 in a cluster; pedicels jointed at the middle, epicalyx absent, complete, bisexual, regular, actinomorphic, hypogynus, pentamerous, yellow.
Sepals: five, gamosepalous, campanulate, slightly accrescent, persistent, valvate.
Petals: five, polypetalous but slightly connate below and jointed with the staminal column, twisted.
Stamens many, monadelphous, arranged on the staminal column; staminal column is shorter than the petals, divided above into numerous filaments, anthers monothecous, reniform, basifixed, filament short, extrorse. Pollen are spherical with spikes, size is approximately 90 microns.
Carples: five, syncarpous, ovary superior, penta or multilocular with axile placentation, one ovule in each locule; style 1, passing through the staminal tube; stigma globular, correspond to the number of carpels.
A schizocarpic mericarp, seed 1 in each mericarp.
I) Reticulate venation.
II) Flower pentamerous.
I) Petals free.
I) Flower hypogynus; ovary superior.
I) Stamens indefinite, monadelphous.
II) Ovary 5 carpellary, placentation axile.
I) Plant: mucilaginous.
II) Leaves: simple with free lateral stipule.
III) Flower: bisexual, petals: five, twisted; monadelphous stamen, anther one-celled, reniform.
I) Staminal column without teeth at apex.
II) Flowers without epicalyx.
III) Ovule 1 in each locule; seed 1 in each mericarp.
I) Leaf base obtuse, apex acute.
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