Stems: from a tufted rootstock. Leaves: alternate, leaflets mostly two to three divided, the divisions from round-oval to oblong-linear. Flowers: dense, corolla with rounded lobes. Fruit: ovules three in each cell.

This species of Greek Valerian grows at high altitudes, the bright blue flowers being erect, fragrant, and growing in densely congested heads. The plant is hairy, the petioles of the radical leaves are conspicuously scarious-dilated and sheathing at the base, and the leaflets are very small, and so crowded that they appear to be growing in fascicles or whorls.

Polemonium humile, or Purple Greek Valerian, has shorter, stouter stems than the preceding species, and is much branched. The leaflets are mostly oblong, and the purplish flowers grow in flat-topped clusters, the ample, rounded lobes of the corolla being much longer than the tube. The seeds are one or two in each cell. This is almost an arctic-alpine plant.