Schemes (A, C) and cross-sections of the achenes (B, D). A, B Tourneuxia variifolia (Tourneuxia clade), B from Bochantsev 862 (LE) C, D Scorzonera villosa (Gelasia clade), D from Rechinger 23425 (B). Designation of the colours in A and C: yellow – thin-walled parenchyma, pink (A) – sclerenchyma obliquely orientated in the region of the wings; red – sclerenchyma (of parallel orientation); blue – seed coat; violet dots (C) – vestiges of vascular bundles in the seed coat; green – endosperm; white areas between pericarp and seed coat designate air cavities; central white area – seed hollow.