Achilleinae K. Bremer & Humphries

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 : 130

= Achilleinae K. Bremer & Humphries in Bull. Nat.

Hist. Mus. London , Bot. 23: 126. 1993. – Type: Achillea L . ( Achillea millefolium L.) .

Description — Subshrubs or perennial or annual herbs. Indumentum of basifixed, sometimes asymmetrically medifixed ( Achillea ) hairs. Leaves alternate or in a basal rosette ( Heliocauta ), rarely entire, usually dentate to 4-pinnatisect, sometimes vermiform. Capitula solitary or in lax to dense corymbs, radiate, disciform or discoid. Involucre hemispheric to cylindric or obconic. Phyllaries in 2 or 3 rows, with narrow to broad scarious margins. Receptacle flat, hemispheric or conic, paleate or epaleate ( Matricaria ); paleae flat to convex or canaliculate. Ray florets female; limb white, yellow or pink; tube ± flattened. Disc florets hermaphrodite; corolla (4 or)5-lobed, basally ± saccate and clasping top of achene; anthers with non-polarized endothecial tissue and a balusterform filament collar. Achenes obovoid, terete with 3–5 weak ribs or dorsiventrally flattened and with 2 lateral ribs or wings; apex marginally rounded or with a narrow marginal corona ( Anacyclus , Matricaria ); pericarp with or without myxogenic cells, sometimes with longitudinal resin ducts ( Achillea , Heliocauta ). Embryo sac development monosporic. Base chromosome number x = 9.

Distribution — Europe, Asia, N Africa, W North America.

Members — Achillea L. (115), [incl. Leucocyclus Boiss. (1), Otanthus Hoffmanns. & Link (1), see Guo & al. (2004), Ehrendorfer & Guo (2005, 2006)], Anacyclus L. (9), Heliocauta Humphries (1), Matricaria L. (6).

Notes — The reciprocal monophyly of the two closely related subtribes Anthemidinae and Matricariinae is not supported by our present analyses. Only when Matricaria is excluded from both subtribes do they receive strong support in the phylogenetic reconstruction based on concatenated sequence information ( Fig. 3). As discussed earlier ( Oberprieler & al. 2007), the main difference between the two subtribes is found in the embryo sac development, which follows a monosporic type in Matricariinae and a tetrasporic one in Anthemidinae . Since a tetrasporic embryo sac development constitutes an apomorphic condition in the otherwise monosporic tribe (with exceptions in Argyranthemum and Heteranthemis in the Glebionidinae ), we cannot exclude the possibility that a monophyletic subtribe Anthemidinae is nested in a paraphyletic Matricariinae . This situation already described in Oberprieler & al. (2007) based on nrDNA ITS sequence information has not been resolved by adding more markers in the present analysis. However, we still refrain from uniting these two embryologically wellseparated generic assemblages without an unequivocal phylogenetic signal.

In contrast to former enumerations, the genus Anacyclus has been reduced in its species number due to the transfer of three species to the genus Cota in the Anthemidinae ( Vitales & al. 2018). Both genera share the character of dorsi-ventrally flattened achenes, but the mentioned sequence-based phylogenetic analysis (nrDNA ITS, cpDNA psbA-trnH) revealed that the three E Mediterranean representatives, A. anatolicus , A. latealatus and A. nigellifolius , do not belong to the W Mediterranean lineage of Anacyclus .