[+] Nutlets armed, attached laterally; corolla short, closed by 5 scales.
2. Cynoglossum. Nutlets horizontally radiate, much produced downward, covered with barbed prickles.
3. Echinospermum. Nutlets erect or ascending, the margin or back armed with barbed prickles.
[+][+] Nutlets not armed, attached more or less laterally.
4. Krynitzkia. Corolla short, white, with closed throat. Nutlets attached along the inner angle.
5. Mertensia. Corolla trumpet-shaped with open throat, usually blue. Nutlets fleshy, attached just above the base.
[+][+][+] Nutlets unarmed, attached by the very base, ovoid, mostly smooth and shining.
[++] Scar flat, small. Racemes leafy-bracteate, except in n. 6.
6. Myosotis. Corolla short salver-form, its lobes rounded, and throat crested.
7. Lithospermum. Corolla salver-form to funnel-form, its rounded lobes spreading; the throat either naked or with low crests.