Sagina L.

Scientific Description

Family Caryophyllaceae.

Subfamily Alsinoideae, Tribe Alsineae.

Habit and leaf form. Dwarf herbs (often tufted); non-laticiferous and without coloured juice. ‘Normal’ plants. Leaves well developed. Plants with roots; non-succulent; unarmed. Annual, or perennial; to 0.32–0.52 m high. Self supporting. Mesophytic. Not heterophyllous. Leaves small to medium-sized; not fasciculate; opposite; with blades; sessile; simple; not peltate. Leaf blades entire; flat; subulate to linear, or ovate. Mature leaf blades adaxially glabrous; abaxially glabrous. Leaves without stipules. Leaf blade margins entire; flat. Leaf anatomy. Hairs absent; glandular hairs absent.

Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite. Floral nectaries absent.

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’, or solitary. Inflorescence few-flowered. Flowers in cymes. Inflorescences compound. The terminal inflorescence unit cymose. Inflorescences terminal. Flowers pedicellate; small; regular; tetracyclic, or tricyclic (rarely). Perianth with distinct calyx and corolla; 8–12, or 4–6; 2 -whorled, or 1 -whorled (rarely); isomerous, or anisomerous (rarely). Calyx present; 4 (rarely), or 5, or 6 (rarely); 1 -whorled; polysepalous; glabrous, or hairy; valvate; persistent, or not persistent. Corolla present, or absent; 0 (rarely), or 4 (rarely), or 5, or 6 (rarely); 1 -whorled, or 0 -whorled; polypetalous; contorted, or imbricate (rarely); white. Petals minute; sessile. Corolla members deeply bifid. Androecium present. Fertile stamens present. Androecial members definite in number. Androecium 4–5, or 8, or 10. Androecial members all equal; free of one another; 1 -whorled, or 2 -whorled. Androecium exclusively of fertile stamens. Stamens 4–5, or 8, or 10; isomerous with the perianth, or diplostemonous (obdiplostemonous). Anthers separate from one another; dehiscing via longitudinal slits; introrse; bilocular; tetrasporangiate. Fertile gynoecium present. Gynoecium 1 carpelled. The pistil 1 celled. Gynoecium syncarpous; synovarious; superior. Ovary unilocular; 1 locular. Gynoecium stylate. Styles 4–5 (alternisepalous); free; simple. Stigmas 4–5; 1 - lobed. Placentation free central, or basal. Ovules in the single cavity 50 (‘numerous’); campylotropous.

Fruit and seed features. Fruit ca 6 mm long; not hairy; dehiscent; a capsule. Dispersal unit the seed. Fruit 50 seeded (‘numerous’). Perisperm present. Seeds minute.

Geography, cytology, number of species. Holarctic. Adventive. Not endemic to Australia. Australian states and territories: Western Australia, South Australia, Northern Territory, Queensland, New South Wales, Victoria, Australian Capital Territory, and Tasmania. 2n=18, 20, 22, 22–24, 28, 30, 36, 42, 44, 46, 56, 60, 64, 66, 84, 88, 100. A genus of ca 25 species; 3 species in Western Australia; 0 endemic to Western Australia.