Sherardia arvensis L. - Field Madder

Sherardia arvensis plant

Family - Rubiaceae

Stems - Multiple from the base, sprawling to ascending, to +40cm long, herbaceous, 4-angled, hispidulous below, glabrescent apically.

Sherardia arvensis stem

Leaves - Sessile, in whorls of 6, oblong, to +/-8mm long, 3-4mm broad, pubescent adaxially and ciliate on the midrib abaxially, entire, acute, with strigillose margins. The margin of the leaf translucent at least at the apex (use a lens to see). Lowest leaves obovate to oblanceolate.

Sherardia arvensis leaves

Inflorescence - Axillary bracteate fascicles of typically 3 flowers. Peduncles to 1cm long in fruit, 1-2mm long in flower, 4-angled, glabrous to sparse pubescent. Bracts subtending the flowers foliaceous, accrescent, lanceolate, 3-nerved, to 8mm long and 3mm broad in fruit, strigose externally, glabrous internally.

Flowers - Corolla 4-lobed, funnelform, 4-5mm long, pinkish-purple. Corolla tube to 3mm long, whitish at the base, glabrous externally and internally. Corolla lobes acute, spreading, -2mm long, 1mm broad, glabrous. Stamens 4, exserted, adnate at the apex of the corolla tube. Filaments white, glabrous, 1.1mm long. Anthers purplish, .3mm long. Style exserted, glabrous, translucent, 4mm long. Stigmas 2, short (.1mm long). Calyx 1.1mm long in flower, accrescent, 6-lobed, pubescent, green. Calyx lobes triangular, .3mm long. Fruits mostly on stalks to .5mm long, pubescent. slightly rectangular in cross-section, to 4mm long, 2-locular, 2-seeded.

Sherardia arvensis flowers

Sherardia arvensis fruitsFruits.

Flowering - April - May.

Habitat - Openings in woods, along creeks, disturbed sites, fields, roadsides.

Origin - Native to Europe.

Other info. - This little species is uncommon in Missouri. It is found only in several southwestern counties. The plant, at first glance, appears to be in the genus Galium but its purplish flowers, funnelform corolla and bracteate inflorescences separate it from that genus. The plant can be quite weedy if left un-checked and it will most certainly expand its range in Missouri with time.

Photographs taken somewhere in North Carolina, 4-20-03, and in Auburn, AL., 5-14-05.


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