Bupleurum L.

Scientific Description

Family Apiaceae.

Habit and leaf form. Herbs, or shrubs (rarely); bearing essential oils, or without essential oils (?); resinous, or not resinous (?). Annual, or perennial; plants with a basal concentration of leaves, or with neither basal nor terminal concentrations of leaves (?). Helophytic, or mesophytic (?). Leaves small to medium-sized; alternate; ‘herbaceous’, or leathery (?); perfoliate; gland-dotted, or not gland-dotted (?); aromatic, or foetid, or without marked odour (?); simple; peltate, or not peltate (?); pulvinate, or epulvinate (?). Leaf blades entire; parallel-veined. Leaves with stipules, or without stipules (?). Leaf blade margins entire. Leaves without a persistent basal meristem. Leaf anatomy. Hairs absent. Stem anatomy. Nodes multilacunar, or tri-lacunar (?). Secondary thickening developing from a conventional cambial ring, or anomalous (?); from a single cambial ring.

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

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; in umbels. Inflorescences compound. The terminal inflorescence unit cymose, or racemose (?). Inflorescences terminal; with involucral bracts, or without involucral bracts; pseudanthial. Flowers ebracteate (usually), or bracteate; bracteolate. Bracteoles 4–7, forming the conspicuous involucre around the compound inflorescence. Flowers small; regular to somewhat irregular (?); 5 merous (except for the gynoecium); cyclic; tetracyclic, or tricyclic. Free hypanthium absent. Perianth petaline (usually), or with distinct calyx and corolla (but sepals indistinct); 5, or 10; 1 -whorled (usually), or 2 -whorled; isomerous; yellow, or green to yellow. Calyx present, or vestigial, or absent; when detectable, 5; 1 -whorled; persistent; with the median member posterior. Corolla 5; 1 -whorled; polypetalous; valvate; unequal but not bilabiate, or regular; yellow, or green to yellow. Petals more or less orbicular. Corolla members entire. Androecium 5. Androecial members free of the perianth; all equal to markedly unequal; free of one another; 1 -whorled. Androecium exclusively of fertile stamens. Stamens 5; isomerous with the perianth; oppositisepalous; inflexed in bud. Anthers dehiscing via longitudinal slits; introrse; tetrasporangiate. Gynoecium 2 carpelled. The pistil 2 celled. Gynoecium syncarpous; synovarious; inferior. Ovary plurilocular; 2 locular. Gynoecium median. Epigynous disk present. Gynoecium stylate. Styles 2; free to partially joined (their bases thickened into a low, entire stylopodium crowning the ovary); apical. Stigmas wet type; non-papillate; Group IV type. Placentation axile, or apical (?). Ovules 1 per locule, or 2 per locule (usually two, but one abortive ?); pendulous; epitropous; non-arillate; anatropous.

Fruit and seed features. Fruit non-fleshy; a schizocarp. Mericarps 2 (with 5 filiform or narrow-winged, conspicuous ridges). Seeds endospermic. Endosperm oily. Embryo well differentiated. Cotyledons 2. Embryo achlorophyllous; straight. Seedling. Germination phanerocotylar.

Physiology, biochemistry. Aluminium accumulation not found. Photosynthetic pathway: C₃.

Geography, cytology, number of species. Adventive. Australian states and territories: Western Australia, South Australia, Queensland, New South Wales, and Victoria.

Additional characters Petals inflexed.