Melilotus officinalis (L.) Pall.

Melilotus officinalis plant

Family - Fabaceae

Stems - To +2m tall ,erect, herbaceous, from taproot, branching above, glabrous to sparse pubescent, with musky scent when cut or crushed.

Melilotus officinalis stem

Leaves - Alternate, trifoliolate, stipulate. Stipules to 5mm long, subulate. Leaflets with petiolules. Center leaf with petiolule to 5mm long. Lateral leaflets with petiolules to +/-1mm long. All leaflets variable in shape from oblong to oblanceolate, serrulate, typically truncate at apex and mucronate, glabrous to sparse pubescent.

Melilotus officinalis leaf

Inflorescence - Axillary racemes near apex of stems. Peduncles sparsely appressed pubescent. Raceme to +/-8cm long, indeterminate, +/-50 flowered. Pedicels 2.5mm long, pilose, subtended by tiny lanate subulate bract to 1.5mm long.

Melilotus officinalis inflorescence

Flowers - Corolla yellow, papilionaceous. Standard 3.5-4mm broad, 5-6mm long. Stamens diadelphous, 4mm long. Filaments glabrous. Anthers yellow. Ovary green, 1.2mm long, glabrous. Style glabrous, 2.7mm long. Calyx tubular, +2mm long, 5-toothed. Teeth subequal, +/-1mm long. Fruit to 5mm long, compressed, glabrous.

Melilotus officinalis calyxCalyx.

Melilotus officinalis flowers

Flowering - May - October.

Habitat - Fields, pastures, disturbed sites, waste ground, roadsides, railroads.

Origin - Native to Eurasia.

Other info. - It's hard to miss this plant in early summer as it is growing nearly everywhere. The yellow flowers are a big favorite of bees and the genus name means "Honey Lotus".
As noted above, the plant produces a musky scent when cut or crushed and the scent can make some people nauseous. This scent is caused by coumarins contained in the plant. Personally, I get a headache if I pass through a dense area of the plants that has recently been cut. At one time the plant was used as an insect repellent on textiles.

Photographs taken near Alley Spring, Shannon County, MO., 6-6-03.


Back