Leucanthemopsidinae Oberpr. & Vogt

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 : 131-132

14. Leucanthemopsidinae Oberpr. & Vogt in Willdenowia 37: 104. 2007. – Type: Leucanthemopsis (Giroux) Heywood ( Leucanthemopsis alpina (L.) Heywood).

Description — Annual or perennial herbs. Indumentum of medifixed hairs. Leaves alternate or sometimes opposite ( Phalacrocarpum ), serrate-dentate to 1- or 2-pinnatisect. Capitula solitary, radiate. Involucre hemispheric. Phyllaries in 4 rows, with broad scarious margins. Receptacle convex, epaleate, sometimes hairy ( Phalacrocarpum ). Ray florets female or neuter; limb white or yellow, sometimes reddish ( Phalacrocarpum ). Disc florets hermaphrodite, rarely ( Phalacrocarpum ) functionally male; corolla 5-lobed; anthers with non-polarized endothecial tissue and a balusterform filament collar. Achenes obovoid, round in cross-section and with (3–)5–10 ribs, rarely dorsiventrally compressed and with 1 adaxial, 2 lateral and 2 abaxial ribs ( Prolongoa ); apex with a scarious corona or marginally rounded ( Castrilanthemum , Phalacrocarpum ); pericarp with myxogenic cells along ribs (without myxogenic cells in Phalacrocarpum ), without resin sacs. Embryo sac development monosporic (only known in Leucanthemopsis ). Base chromosome number x = 9.

Distribution — SW Europe, NW Africa.

Members — Castrilanthemum Vogt & Oberpr. (1), Hymenostemma Willk. (1), Leucanthemopsis (Giroux) Heywood (9), Phalacrocarpum (DC.) Willk. (1), Prolongoa Boiss. (1).

Notes — In contrast to the phylogenetic reconstructions based on nrDNA ITS ( Fig. 2), both the gene tree based on plastid markers (Fig. 1) and the two species trees ( Fig. 3, 4) strongly support the sister-group relationship of the Iberian endemic genus Phalacrocarpum and the closely knit generic assemblage of subtribe Leucanthemopsidinae . Tomasello & al. (2015) dated the divergence between Phalacrocarpum and the three other genera to c. 20 Ma and the further differentiation among the latter to the range between 7 Ma (divergence of Hymenostemma and Prologoa) and 17 Ma (divergence of Castilanthemum). Caused by the extremely long periods of evolutionary independence exhibited by the five lineages, the morphological diversity of the subtribe is considerable and gains even more heterogeneity by inclusion of Phalacrocarpum . However, erection of an independent, unigeneric subtribe for the latter genus would immediately question the treatment of the remaining genera as a single subtribal entity.

The infrageneric taxonomy of both the enigmatic Phalacrocarpum and the much younger genus Leucanthemopsis is complicated by evolutionary reticulations due to homoploid and polyploid hybrid speciation, respectively. Molecular-based analyses on species delimitations in the two genera were done by Criado Ruiz & al. (2021) and Tomasello & Oberprieler (submitted) and partially question the morphology-based taxonomic treatments proposed in Flora iberica ( Pedrol 2019; Nieto Feliner 2019).

IV. Mediterranean clade