In addition to the setae with an enlarged base. known for many genera of the Boraginaceae, many species of Onosma have setae with usually 4-20 rays arising from the base. These are referred to as stellate setae, and are fully described by Javorka (loc.sit). The central seta is occasionally absent from these hairs, but usually it is distincly longer and stouter than the rays. The description of the stellate setae in this account are of those found on the lower leaves.
The genus presents considerable taxonomic difficulties , particularly in C. & S.E Europe, which cannot be resolved without experimental investigation. The presence or absence of stellate setae is widely used as major character in the genus, but in a number of species (particularly 13-20) ther may be a wde range of variation in the presence, frequency and length of the stellate setae. There has, in the past, been considerable nomemclatural confusion and the following names have been widely misapplied: O.echiodes, O.setosa, O.stellulata and O.taurica
All species occur in dry, sunny habitats.
Species and images:
