Oxalis x vanaelstii Hoste, Meeus & Groom, 2021

Groom, Quentin, Meeus, Sofie, Janssens, Steven B., Leus, Leen & Hoste, Ivan, 2021, Hybridization of Oxalis corniculata and O. dillenii in their non-native range, PhytoKeys 178, pp. 17-30 : 17

Oxalis x vanaelstii Hoste, Meeus & Groom sp. nov.

Type material.

Holotype. Belgium. • Bellem, Aalter; 51.09°N, 3.49°E; 31 Oct. 2016; Ivan Hoste 16054 (holotype: BR (BR0000025668254V); isotype: K, isotype: MO).

Paratypes. Belgium. • Cultivated at Meise Botanic Garden; Quentin Groom 19001 (BR (BR0000025668247V)). • Cultivated at Meise Botanic Garden; Ivan Hoste & Quentin Groom S.N. (BR (BR0000025668209V)).

Diagnosis.

Intermediate in characters between its parents O. corniculata and O. dillenii . Prostrate to ascending, mid-sized stipules, stem hairs antrorse, not tightly appressed to the stem. Flowers with at most weak orange marks in the throat, marks sometimes absent.

Description.

A short-lived perennial, prostrate to ascending, herb with a thin taproot. Leaves trifoliolate with three similarly sized, heart-shaped leaflets. A narrow stipule is fused to the base of the petiole and is intermediate in width between O. corniculata and O. dillenii . The stem hair density is moderate with simple, arcuate, antrorse, pointed hairs. Not strongly appressed to the stem as in O. dillenii . The leaves are green or purple-brown, though if purple, not as darkly colored as Oxalis corniculata var. atropurpurea . The flowers are yellow, sometimes with weak orange streaks in the throat. Fruits are unknown.

Etymology.

Oxalis x vanaelstii is named to commemorate the Belgian naturalist, conservationist and mycologist Etienne Vanaelst (1948-2017) who, as a volunteer collaborating with mycologists at Ghent University, contributed to a better understanding of the diversity of mushrooms, especially those growing in and around his hometown, Knesselare (prov. of East Flanders).

Habitat.

Gardens.

Distribution area.

Europe and Japan where parental distribution overlaps. The hybrid is also highly likely to occur in North America where the parents also co-occur ( Eiten 1963).