Galium boreale L.
Family - Rubiaceae
Stems - Multiple from the base, branching, herbaceous, 4-angled, to +/-40cm long, ascending to erect or reclining, glabrous to sparse retrorse strigose, with bumps and the angles, from a small crown and fibrous roots.
Leaves - Whorled, 4 at a node, sessile, linear-lanceolate, to +/-4cm long, +5mm broad, with three main nerves, entire, with ciliate margins, glabrous above, sparsely pubescent below, green above, light green below. Veins of leaf impressed above, expressed below.
Inflorescence - Terminal cymes to +10cm long and broad. Each division of the cyme subtended by a pair of elliptic bracts. Bracts reduced upward, with retrorse hairs at the base. Pedicels and peduncles of cyme glabrous, 4-angled, often with hairs in their axils. Pedicels to 4mm long.
Flowers - Corolla white, 4-lobed, +/-3mm broad. Corolla tube conic, -1mm long. Lobes acute, glabrous, +1mm long and broad, ovate-oblong, entire. Stamens 4, alternating with the corolla lobes, adnate at the apex of the corolla tube, erect, exserted. Filaments to .7mm long, white, glabrous. Anthers yellow-brown, .2-.3mm long. Style 1, glabrous, white, slightly exserted, bifurcate in the apical 1/2, +1mm long. Stigmas capitate, translucent, .1-.2mm broad. Ovary inferior, light green, with antrorse hairs, bilobed, .7mm long in flower, .8mm broad.
Flowering - May - July.
Habitat - North-facing ledges and crevices of limestone bluffs.
Origin - Native to U.S.
Other info. - This species is extremely rare in Missouri and can only be found in two counties in the state. The plant is a relict from before the retreat of the Pleistocene ice sheets. It has remained only in the cool, north-facing bluffs along the Jack's Fork River.
Photographs taken along the Jack's Fork River, Shannon County, MO., 6-22-03.