Soleirolia Gaudich.

Scientific Description

Family Urticaceae.

Habit and leaf form. Herbs. Annual, or perennial. Mesophytic. Leaves small to large; alternate; spiral; petiolate; non-sheathing; simple. Leaf blades entire; conspicuously asymmetric, or not conspicuously asymmetric; flat; orbicular (to reniform); pinnately veined, or palmately veined; cross-venulate. Leaves without stipules. Leaf blade margins entire, or serrate, or dentate. Leaves without a persistent basal meristem. Leaf anatomy. Urticating hairs present, or absent. Stem anatomy. Secondary thickening developing from a conventional cambial ring.

Reproductive type, pollination. Fertile flowers functionally male and functionally female. Unisexual flowers present. Plants monoecious. Male flowers with pistillodes, or without pistillodes. Anemophilous. Pollination mechanism conspicuously specialized (the filaments reflexing violently).

Inflorescence and flower features. Flowers solitary; axillary. Inflorescences flowers in the upper axils female, those in the lower axils male. Flowers bracteate; bracteolate; minute, or small; regular; 4 merous. Hypogynous disk absent. Perianth sepaline, or vestigial to absent (sometimes, in female flowers); 4; 1 -whorled; joined; persistent; accrescent. Calyx present; (the perianth being thus interpreted) 4; 1 -whorled; gamosepalous; blunt-lobed; imbricate, or valvate; of female flowers, tubular; regular; persistent; accrescent. Fertile stamens present, or absent (female flowers). Androecial members definite in number. Androecium 4. Androecial members free of the perianth; free of one another; 1 -whorled. Androecium exclusively of fertile stamens. Stamens 4; isomerous with the perianth; oppositisepalous; inflexed in bud (uncoiling elastically); filantherous. Anthers dorsifixed; dehiscing via longitudinal slits; introrse; tetrasporangiate. Fertile gynoecium present, or absent (male flowers). Gynoecium ostensibly 1 carpelled (i.e. with no obvious evidence of more than one carpel). The pistil 1 celled. Carpels reduced in number relative to the perianth. Gynoecium monomerous (ostensibly), or syncarpous (theoretically); of one carpel (at least, usually with no evidence of syncarpy), or synstylovarious to eu-syncarpous (theoretically); superior. Carpel (if treated as monomeric) shortly stylate, or non-stylate; apically stigmatic; (if the gynoecium is considered monomerous) 1 ovuled. Placentation basal. Ovary unilocular; (if the gynoecium is considered pseudomonomerous) 1 locular. Gynoecium non-stylate, or stylate. Placentation if recognised as syncarpous, basal. Ovules in the single cavity 1; funicled, or sessile; ascending; non-arillate; orthotropous to hemianatropous.

Fruit and seed features. Fruit non-fleshy. The fruiting carpel indehiscent; (if the gynoecium is considered monomerous) nucular. Fruit indehiscent; (if the gynoecium is considered syncarpous) a nut; 1 seeded. Seeds scantily endospermic, or non-endospermic. Endosperm oily, or not oily. Cotyledons 2. Embryo straight.

Geography, cytology, number of species. Adventive. Australian states and territories: Western Australia, South Australia, New South Wales, Victoria, and Tasmania. South-West Botanical Province. 1 species in Western Australia; 0 endemic to Western Australia.

Etymology. After Joseph Fran‡ois Soleirol (1796–1863), who collected in Corsica.