Samolus L.

Scientific Description

Family Primulaceae.

Habit and leaf form. Erect or ascending herbs; with coloured juice, or non-laticiferous and without coloured juice. Annual, or perennial; plants with a basal concentration of leaves, or with neither basal nor terminal concentrations of leaves. Young stems cylindrical. Arising from a tufted or creeping rootstock. Helophytic to xerophytic. Leaves alternate; spiral; petiolate to sessile; non-sheathing; gland-dotted; simple. Leaf blades entire; pinnately veined; cross-venulate. Leaves without stipules; without a persistent basal meristem. Leaf anatomy. Hydathodes present. Stem anatomy. Nodes unilacunar. Secondary thickening absent, or developing from a conventional cambial ring, or anomalous.

Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite. Entomophilous.

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; in racemes, or in corymbs. Inflorescences scapiflorous, or not scapiflorous; terminal; long or short. Flowers pedicellate; bracteate; ebracteolate; small, or medium-sized; regular; 5 merous; cyclic; tetracyclic, or pentacyclic. Free hypanthium absent. Perianth with distinct calyx and corolla; 10; 2 -whorled; isomerous. Calyx 5; 1 -whorled; gamosepalous; lobed; imbricate, or contorted; campanulate; regular; persistent (the tube adnate to about the middle of the ovary); with the median member posterior. Corolla 5; 1 -whorled; appendiculate (with staminodal scales); gamopetalous (tube short); lobed; imbricate; regular; white to cream, or pink. Corolla members entire. Androecium 10. Androecial members adnate (to the corolla); free of one another; 1 -whorled, or 2 -whorled. Androecium including staminodes. Staminodes 5 (alternating with the stamens); non-petaloid (filiform). Stamens 5; isomerous with the perianth; alternisepalous. Filaments glabrous. Anthers dorsifixed; straight, or recurved; versatile; dehiscing via longitudinal slits; introrse; tetrasporangiate; appendaged, or unappendaged. The anther appendages apical (blunt or acute). Gynoecium supposedly 5 carpelled. The pistil 1 celled. Carpels isomerous with the perianth. Gynoecium syncarpous; eu-syncarpous; partly inferior. Ovary unilocular; 1 locular (and no evidence of partitions). Gynoecium stylate. Styles 1; attenuate from the ovary; apical. Stylar canal present. Stigmas 1; 1 - lobed; capitate; dry type; papillate, or non-papillate; Group II type. Placentation free central (placenta ovoid, extending in a horn-like projection almost to the apex of the cavity). Ovules in the single cavity (5–)7–100 (? usually ‘many’); ascending; non-arillate; anatropous, or hemianatropous.

Fruit and seed features. Fruit non-fleshy; dehiscent; a capsule. Capsules valvular (opening by 5 valves). Fruit 2–100 seeded (? i.e. to ‘many’). Seeds endospermic. Endosperm oily. Seeds with amyloid. Cotyledons 2. Embryo straight. Seedling. Germination phanerocotylar.

Physiology, biochemistry. Aluminium accumulation not found.

Geography, cytology, number of species. Native of Australia. Not endemic to Australia. Australian states and territories: Western Australia, South Australia, Northern Territory, Queensland, New South Wales, and Victoria. Northern Botanical Province, Eremaean Botanical Province, and South-West Botanical Province.

Additional characters Corolla lobes spreading (obtuse).