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Borago L.

Sp.Pl. 2:137 (1753)
Name Status

Scientific Description

Common name. Borages. Family Boraginaceae.

Habit and leaf form. Herbs; without essential oils. Autotrophic. Annual. Leaves basal and cauline. Plants initially with a basal concentration of leaves; to 0.8 m high. Helophytic, or mesophytic, or xerophytic. Leaves medium-sized; alternate and opposite (then opposite below); petiolate to subsessile (basally), or sessile (above); non-sheathing; not gland-dotted; simple; epulvinate. Leaf blades dorsiventral, or isobilateral; entire; flat; linear to lanceolate; ovate, or obovate, or elliptic; cross-venulate. Mature leaf blades adaxially pubescent; abaxially pubescent. Leaves without stipules. Leaf blade margins entire. Leaves without a persistent basal meristem. Leaf anatomy. Hairs present (with a broad multicellular base). Urticating hairs absent. Stem anatomy. Secondary thickening developing from a conventional cambial ring.

Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite. Floral nectaries present. Nectar secretion from nectary scales around each ovary lobe. Entomophilous.

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; in cymes. Inflorescences simple. The terminal inflorescence unit cymose (coiled at first). Inflorescences terminal; not pseudanthial. Flowers pedicellate; bracteate; bracteolate; small to medium-sized; regular; 5 merous; cyclic; tetracyclic. Free hypanthium absent. Hypogynous disk present, or absent. Perianth with distinct calyx and corolla; 10; 2 -whorled; isomerous. Calyx present; 5; 1 -whorled; gamosepalous; lobed. Calyx lobes markedly longer than the tube. Calyx imbricate, or open in bud, or valvate. Degree of gamosepaly, maximum length joined/total calyx length to 0.3. Calyx neither appendaged nor spurred; persistent; accrescent. Calyx lobes elliptic, or triangular, or linear. Corolla present; 5; 1 -whorled; appendiculate (with a corona of 5 scales from the throat protecting the nectar); gamopetalous; lobed. Corolla lobes markedly longer than the tube. Corolla imbricate, or contorted; rotate; regular; glabrous abaxially; scales hairy adaxially; white, or blue. Corolla lobes elliptic. Fertile stamens present. Androecial members definite in number. Androecium 5. Androecial members unbranched; adnate (to the corolla); all equal; free of one another; 1 -whorled. Androecium exclusively of fertile stamens. Stamens 5. Staminal insertion in the throat of the corolla tube. Stamens becoming exserted; all more or less similar in shape; isomerous with the perianth; oppositisepalous; filantherous (to subsessile). Anthers separate from one another; dorsifixed to basifixed; straight; dehiscing via longitudinal slits; introrse; tetrasporangiate; appendaged. The anther appendages apical (and straight). Gynoecium 2 carpelled. The pistil 4 celled. Carpels reduced in number relative to the perianth. Gynoecium syncarpous; eu-syncarpous; superior. Ovary plurilocular (4-lobed); 2 locular (‘really’, but rarely ostensibly so), or 4 locular (ostensibly, via false septa). Locules secondarily divided by ‘false septa’. Gynoecium median; stylate. Styles 1; simple; from a depression at the top of the ovary; ‘gynobasic’; becoming exserted. Stigmas 1; 1 - lobed; indistinct. Placentation axile to basal. Ovules differentiated; 2 per locule (i.e. per true locule), or 1 per locule (per cell, when the gynoecium separating into one-ovuled portions); horizontal to ascending; epitropous; non-arillate; anatropous, or hemianatropous.

Fruit and seed features. Fruit aerial; non-fleshy; not spinose; a schizocarp. Mericarps comprising achenes, or comprising nutlets, or comprising drupelets. Seeds endospermic, or non-endospermic. Cotyledons 2. Embryo straight, or curved.

Special features. Corolla tube straight.

Etymology. Possibly from the Latin for "a hairy garment", referring to the leaves.

H.R. Coleman, 8 September 2016

Taxonomic Literature

  • Wheeler, Judy; Marchant, Neville; Lewington, Margaret; Graham, Lorraine 2002. Flora of the south west, Bunbury, Augusta, Denmark. Volume 2, dicotyledons. Australian Biological Resources Study.. Canberra..
  • Blackall, William E.; Grieve, Brian J. 1981. How to know Western Australian wildflowers : a key to the flora of the extratropical regions of Western Australia. Part IIIB, (Epacridaceae-Lamiaceae). University of W.A. Press.. [Perth]..