Betoideae

Betoideae
Beta vulgaris subsp. maritima
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Core eudicots
Order:	Caryophyllales
Family:	Amaranthaceae
Subfamily:	Betoideae Ulbr.
Genera
about 6 genera, see text

The Betoideae is a small subfamily of the flowering plant family Amaranthaceae, formerly classified in family Chenopodiaceae. Commonly known members include beet, chard, and mangelwurzel.

Description

The species of Betoideae are annuals, biennial or perennial herbs, vines (Hablitzia) or subshrubs. The flowers have 5 tepals (Aphanisma only 3) and 5 stamens (Aphanisma only one). The fruits of Betoideae are capsules that open with a circumscissile lid.

In tribe Beteae, the perianth is basally indurated in fruit, and the stamens a basally inserted to a thickened bulge surrounding the visible part of the ovary. In tribe Hablitzieae, the tepals are not modified in fruit and membranous, and the stamens are basally united in a membranous ring.

Distribution and evolution

Most genera are distributed in Western and Southern Europe, in the Mediterranean and Southwest Asia, but one disjunct genus, Aphanisma, lives at the coasts of California.

The age of the subfamily ist estimated to be 48.6-35.4 million years old. The areals of Aphanisma in California and Oreobliton in North-Africa are interpreted als remnants from a Beringian ancestor, the disjunction circa 15.4-9.2 million years ago.

Systematics

Oskar Eberhard Ulbrich described the subfamily Betoideae in 1934 within the plant family Chenopodiaceae. He subdivided the taxon into two tribes, Hablitzieae and Beteae with only one genus, Beta. Phylogenetic research by Kadereit et al. (2006) confirmed this classification. But some species traditionally grouped in genus Beta, do now belong to tribe Hablitzieae and were named Patellifolia.

The subfamily Betoideae is regarded as a monophyletic taxon. It comprises 5-6 genera with about 13-20 species.

• Tribus Beteae Moq.:
  • Beta L., about 7-12 species in West-Europe, Mediterranean, Southwest-Asia, with the important crops:
    • Chard, Beetroot, Mangelwurzel, Sugar beet
• Tribus Hablitzieae Ulbr.:
  • Aphanisma Nutt. ex Moq., with one species:
    • Aphanisma blitoides Nutt. ex Moq., an annual plant on Californian beaches
  • Hablitzia M.Bieb., with one species
    • Hablitzia tamnoides M.Bieb., a vine in the forests of the Caucasian floristic region
  • Oreobliton Durieu, with one species
    • Oreobliton thesioides Durieu & Moq., a subshrub in North-Africa, growing on chalk rocks in the Atlas mountains
  • Patellifolia (Syn. Beta sect. Procumbentes Moq.), perennial procumbent herbs, with 3 species:
    • Patellifolia patellaris (Moq.) A.J. Scott & al. (Syn. Beta patellaris Moq.), on Canary Islands and in the western Mediterranean (Spain, Balearic islands, Sicily, Marocco)
    • Patellifolia procumbens (Chr. Sm.) A.J. Scott & al. (Syn. Beta procumbentes Chr. Sm.), on Canary Islands
    • Patellifolia webbiana (Moq.) A.J. Scott & al. (Syn. Beta webbiana Moq.), on Canary Islands
• Classification not sure:
  • Acroglochin Schrad. ex Schult., with 1-2 species
    • Acroglochin persicarioides (Poiret) Moq,

References

• G. Kadereit, S. Hohmann & J.W. Kadereit (2006): A synopsis of Chenopodiaceae subfam. Betoideae and notes on the taxonomy of Beta. - In: Willdenowia 36, p. 9-19.