The genus Patellifolia was published in 1977 by A J Scott, Brian V. Ford-Lloyd and J. Trevor Williams, with the type species Patellifolia webbiana.
The same authors had described this taxon already in 1976 as Patellaria J.T. Williams, A.J.Scott & Ford-Lloyd, but that was an illegitimate name, (because the lichen genus Patellaria Hoffmann was published earlier in 1789).

These plants were first grouped together in 1927 by Vladimir Andreevich Tranzschel as an informal unranked taxon Patellares in the genus Beta.
In 1934, Oskar Eberhard Ulbrich placed them in a new section Beta sect.
Procumbentes.
Until 2006, Patellifolia was often not accepted as a separate genus.
But recent molecular genetic studies by Kadereit et al. (
2006) and Romeiras et al. (
2016) revealed a deep genetic differentiation between Beta and Patellifolia and confirmed the status as own genus.

Patellifolia comprises one to three species:
Patellifolia patellaris (Moq.)
A.J. Scott & al. (
Syn.
Beta patellaris Moq.),
in dry coastal sites or on rocks, widely distributed in Macaronesia (Canary Islands, Madeira, Cape Verde) and in the western Mediterranean (Spain, Balearic islands, Sicily, Morocco), North Africa, to the Horn of Africa.

Patellifolia procumbens (Chr.
Sm.)
A.J. Scott & al. (
Syn.
Beta procumbens Chr.
Sm.),
in dry coastal sites in Macaronesia (Canary Islands, Madeira, Cape Verde).

Patellifolia webbiana (Moq.)
A.J. Scott & al. (
Syn.
Beta webbiana Moq.),
endemic on Gran Canaria, in ruderal nitrophilous sites, Critically Endangered.

It was suggested that Patellifolia procumbens and Patellifolia webbiana might not be different species.
The identification of the three species is difficult, and some distinguishing characters were found to be unreliable.
Therefore, Thulin et al. (
2010) proposed to treat all members of Patellifolia as a single variable species, Patellifoia procumbens.
This proposal was followed in the Euro+Med Plant Base.

But Patellifolia patellaris could not be hybridised with the other two species, supporting the rank of an own species.
The island species evolved recently, and because of their isolation they developed only small genetic differentiation.
As a result, they show only weak genetic barriers to hybridization.
The genus Patellifolia was published in 1977 by A J Scott, Brian V. Ford-Lloyd and J. Trevor Williams, with the type species Patellifolia webbiana. The same authors had described this taxon already in 1976 as Patellaria J.T. Williams, A.J.Scott & Ford-Lloyd, but that was an illegitimate name, (because the lichen genus Patellaria Hoffmann was published earlier in 1789).
These plants were first grouped together in 1927 by Vladimir Andreevich Tranzschel as an informal unranked taxon Patellares in the genus Beta. In 1934, Oskar Eberhard Ulbrich placed them in a new section Beta sect. Procumbentes. Until 2006, Patellifolia was often not accepted as a separate genus. But recent molecular genetic studies by Kadereit et al. (2006) and Romeiras et al. (2016) revealed a deep genetic differentiation between Beta and Patellifolia and confirmed the status as own genus.
Patellifolia comprises one to three species:
Patellifolia patellaris (Moq.) A.J. Scott & al. (Syn. Beta patellaris Moq.), in dry coastal sites or on rocks, widely distributed in Macaronesia (Canary Islands, Madeira, Cape Verde) and in the western Mediterranean (Spain, Balearic islands, Sicily, Morocco), North Africa, to the Horn of Africa.
Patellifolia procumbens (Chr. Sm.) A.J. Scott & al. (Syn. Beta procumbens Chr. Sm.), in dry coastal sites in Macaronesia (Canary Islands, Madeira, Cape Verde).
Patellifolia webbiana (Moq.) A.J. Scott & al. (Syn. Beta webbiana Moq.), endemic on Gran Canaria, in ruderal nitrophilous sites, Critically Endangered.
It was suggested that Patellifolia procumbens and Patellifolia webbiana might not be different species. The identification of the three species is difficult, and some distinguishing characters were found to be unreliable. Therefore, Thulin et al. (2010) proposed to treat all members of Patellifolia as a single variable species, Patellifoia procumbens. This proposal was followed in the Euro+Med Plant Base.
But Patellifolia patellaris could not be hybridised with the other two species, supporting the rank of an own species. The island species evolved recently, and because of their isolation they developed only small genetic differentiation. As a result, they show only weak genetic barriers to hybridization.
Patellifolia