Figure 1. Stem with opposite leaves and interpetiolar stipule (IS).

Figure 2. Colleter, multicellular gland, in cross-section, showing central glandular port and multicellular surface.

Figure 3. Flowers of Gentianales. (a) Symbolanthus (Gentianaceae), with basally fused calyx and trumpet-shaped fused corolla. (b) Cross-section of typical Rubiaceae flower showing inferior ovary, calyx, corolla, and stamens inserted into corolla tube. (c) Cross-section of typical Gentianaceae and Loganiaceae flower, showing superior ovary, otherwise the same as (b).

Figure 4. Seed from Asclepias (Apocynaceae), showing tuft of hairs on one end.

Figure 5. Flower (a) of Asclepias (Apocynaceae), showing intricately formed appendages on corolla, fused staminal parts around style and (b) magnified pollinia with ‘handles’ (called translator).

Figure 6. Flower bud with contort corolla bud in Gentianaceae. Note calyx fused at the base and two leaves at the base of the flower.

Figure 7. Synopsis of phylogenetic relationships in Gentianales. Characteristics for families and groups of families are noted.