Lithospermum L.
Annual, biennial or perennial herbs, sometimes shrubs, hispid or with soft hairs. Infl. short, strongly bracteate, cymose, often terminal. Calyx 5-lobed, sometimes divided to base, persistent. Corolla cylindric, usually funnelform, rarely salverform; tube > lobes, with 5 longitudinal folds; lobes white, yellowish, blue or purple; throat with bands of hairs or scales. Stamens included. Stigma capitate or 2-lobed. Nutlets smooth or tuberculate, shining, very hard.
Key
c. 50 spp., N. Hemisphere, especially Mediterranean, a few in S. America. Naturalised spp. 2.
The 2 spp. described below are sometimes segregated as part of a separate genus Buglossoides Moench on the basis of the longitudinal hairy bands in the corolla throat, as opposed to various types of scales or folds in Lithospermum sens. strict. However, this character is of doubtful importance. A sp. in Lithospermum sens. strict., L. officinale L., gromwell, is occasionally cultivated.
By far the commonest sp. of Lithospermum sens. lat. in N.Z. is the cultivated rock garden, dry bank and garden border plant L. diffusum Lag., now often known as Lithodora diffusa (Lag.) I. M. Johnston. This is a prostrate or semi-prostrate shrublet with linear obtuse lvs and terminal cymes of violet or deep blue funnelform fls.
