Myosotis L.

Scientific Description

Common name. Forget-me-nots. Family Boraginaceae.

Habit and leaf form. Herbs; without essential oils. Autotrophic. Annual to perennial. Leaves basal and cauline. Plants with a basal concentration of leaves; to 0.5 m high. Helophytic, or mesophytic, or xerophytic. Leaves small to very large; alternate; petiolate (at the base), or subsessile to sessile (above); non-sheathing; not gland-dotted; simple; epulvinate. Leaf blades dorsiventral, or isobilateral; entire; flat; linear to lanceolate; ovate, or obovate, or oblong, or elliptic; cross-venulate. Mature leaf blades adaxially glabrous, or pubescent; abaxially glabrous, or pubescent. Leaves without stipules. Leaf blade margins entire. Leaves without a persistent basal meristem. Leaf anatomy. Hairs present (without a much broadened base), or absent. 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 basal nectary around ovary. Entomophilous.

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; in cymes. Inflorescences simple. The terminal inflorescence unit cymose (coiled at first). Inflorescences terminal, or terminal and axillary; of scorpioid cymes, with flowers usually at first densely arranged in 2 rows, becoming more widely spaced and pedicellate when fruiting; not pseudanthial. Flowers subsessile, or pedicellate (in fruit); bracteate, or ebracteate; bracteolate; 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 shorter than the tube to markedly longer than the tube. Calyx imbricate, or open in bud, or valvate; neither appendaged nor spurred; persistent; accrescent. Corolla present; 5; 1 -whorled; appendiculate (with a corona of 5 small scales from the throat protecting the nectar); gamopetalous; lobed. Corolla lobes markedly shorter than the tube, or about the same length as the tube. Corolla imbricate, or contorted; funnel-shaped, or tubular; regular; glabrous abaxially; glabrous adaxially; plain, or with contrasting markings; white, or yellow, or blue. Corolla lobes oblong. 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 all inserted at the same level; remaining included, or becoming exserted (rarely); all more or less similar in shape; isomerous with the perianth; oppositisepalous; filantherous (to subsessile), or with sessile anthers. Anthers dorsifixed to basifixed; dehiscing via longitudinal slits; introrse; tetrasporangiate; appendaged, or unappendaged. The anther appendages when present, apical. 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’; not becoming exserted, or becoming exserted (rarely). Stigmas 1; capitate. Placentation axile to basal. Ovules differentiated; 2 per locule (i.e. per true locule), or 1 per locule (per cell, 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 hairy; not spinose; a schizocarp. Mericarps 1–4; comprising nutlets; shiny (and smooth). Seeds endospermic, or non-endospermic. Cotyledons 2. Embryo straight, or curved.

Special features. Corolla tube straight.

Etymology. From the Greek myosotis; name used by Dioscorides and by Pliny for Asperugo procumbens and by Dioscorides also for Parietaria lusitanica; from the Greek for "mouse" and "ear", referring to the small pointed leaves.