Santolininae Willk.

Oberprieler, Christoph, Töpfer, Alisha, Dorfner, Marco, Stock, Miriam & Vogt, Robert, 2022, An updated subtribal classification of Compositae tribe Anthemideae based on extended phylogenetic reconstructions, Willdenowia 52 (1), pp. 117-149 : 133

18. Santolininae Willk. in Willkomm & Lange, Prodr. Fl. Hispan. 2: 76. 1870. – Type: Santolina L. ( Santolina chamaecyparissus L.) .

Description — Shrubs, subshrubs, perennial or annual herbs. Indumentum of basifixed, medifixed or stellate hairs. Leaves alternate, entire, lobed or dentate to 2- or 3-pinnatisect, sometimes vermiform. Capitula solitary or in lax corymbs, radiate, disciform or discoid. Involucre hemispheric or obconic to urceolate ( Rhetinolepis ), sometimes umbonate ( Mecomischus , Santolina ). Phyllaries in 3 rows, with narrow to broad scarious margins. Receptacle hemispheric to conic, paleate; paleae flat to canaliculate, often with a central resin duct. Ray florets female or neuter; limb white, orange or yellow. Disc florets hermaphrodite; corolla 5-lobed, basally often saccate and clasping top of achene; anthers with non-polarized endothecial tissue and a balusterform filament collar. Achenes obovoid, circular in cross-section, with 3 flimsy ridges (in Santolina 3–5-angled or slightly dorsiventrally flattened); apex marginally rounded; pericarp consisting of large myxogenic cells in longitudinal rows, without resin sacs (in Santolina sometimes without myxogenic cells). Embryo sac development monosporic (only known in Chamaemelum and Cladanthus ). Base chromosome number x = 9.

Distribution — W and S Europe, N Africa, SW Asia.

Members — Chamaemelum Mill. (2), Cladanthus Cass. (5), Mecomischus Coss. ex Benth. & Hook. f. (2), Rhetinolepis Coss. (1), Santolina L. (13).

Notes — The circumscription of Santolininae of Oberprieler & al. (2007) is well-supported both in the cpDNA (Fig. 1) and nrDNA ITS gene trees ( Fig. 2), as well as (for a reduced generic sample comprising Chamaemelum , Cladanthus and Rhetinolepis ) in the species-tree reconstructions ( Fig. 3, 4).