Brodiaeoideae

Brodiaeoideae are a monocot subfamily of flowering plants in the family Asparagaceae, order Asparagales. They have been treated as a separate family, Themidaceae.[1] They are native to Central America and western North America, from British Columbia to Guatemala.[2] The name of the subfamily is based on the type genus Brodiaea.

Brodiaeoideae
Dichelostemma capitatum
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Order: Asparagales
Family: Asparagaceae
Subfamily: Brodiaeoideae
Genera

12 genera (see text)

Distribution

In molecular phylogenetic analyses, Brodiaeoideae is strongly supported as monophyletic. It is probably sister to Scilloideae.[3] Recent treatments have divided Brodiaeoideae (or Themidaceae) into 12 genera.[4] The monophyly of several of the genera remains in doubt.[5] As currently circumscribed, the largest genera are Triteleia, with 15 species, and Brodiaea, with 14.[6] Nine of the 12 genera are known in cultivation, but only species of Brodiaea and Triteleia are commonly grown.[7]

Description

The following description is derived from two sources.[4][8]

Perennial herbs arising from a starchy corm; a new corm arising each year from the old one.

Leaves linear, often fleshy, forming a closed sheath at their base. Veins parallel.

Inflorescence an umbel, or rarely a single flower, at the apex of a solitary scape. Flowers bisexual, actinomorphic. Tepals all similar, in 2 whorls of 3.

Fertile stamens 6, or 3 and alternating with 3 staminodes. Stamens and staminodes inserted on tepals. Anthers basifixed and introrse.

Ovary superior and trilocular.

Fruit a loculicidal capsule. Seed covered with phytomelan.

History

For most of the 19th and 20th centuries, when the group was recognized at all, it was usually at tribal rank and usually called Brodiaeeae. Most authors assigned it to Liliaceae, Alliaceae, or Amaryllidaceae. In 1985, Dahlgren, Clifford, and Yeo treated it as tribe Brodiaeeae of Alliaceae.[9]

Toward the end of the 20th century, it became increasingly evident that the heterogeneous Liliaceae recognized by most authors was several times polyphyletic and that Brodiaea and its relatives were closer to Asparagus than to Allium or Amaryllis. For these reasons, the family Themidaceae was resurrected in an article in Taxon in 1996.[10] The name 'Themidaceae' was first used by Richard Salisbury in 1866.[11] The name was based on the now-defunct genus Themis, which was established by Salisbury along with the family. The only species ever assigned to Themis was Themis ixioides. Its name was changed to Brodiaea ixioides by Sereno Watson in 1879,[12] then to Triteleia ixioides by Edward Lee Greene in 1886.[13] It is known as Triteleia ixioides in Flora of North America.

When the Angiosperm Phylogeny Group published the APG II system in 2003, Themidaceae was treated as an optional circumscription for those who thought that Asparagaceae sensu lato should be divided into smaller segregate families. When the APG III system was published in 2009, Themidaceae was not accepted. In an accompanying article, it was treated as Brodiaeoideae, one of 7 subfamilies in Asparagaceae.[1]

Genera

According to the Angiosperm Phylogeny Website as of May 2011, the genera included in the subfamily are:

References
  1. Chase, M.W.; Reveal, J.L. & Fay, M.F. (2009), "A subfamilial classification for the expanded asparagalean families Amaryllidaceae, Asparagaceae and Xanthorrhoeaceae", Botanical Journal of the Linnean Society, 161 (2): 132–136, doi:10.1111/j.1095-8339.2009.00999.x
  2. Ole Seberg. 2007. "Themidaceae" page 404. In: Vernon H. Heywood, Richard K. Brummitt, Ole Seberg, and Alastair Culham. Flowering Plant Families of the World. Firefly Books: Ontario, Canada.
  3. J. Chris Pires, Ivan J. Maureira, Thomas J. Givnish, Kenneth J. Sytsma, Ole Seberg, Gitte Petersen, Jerrold I. Davis, Dennis W. Stevenson, Paula J. Rudall, Michael F. Fay, and Mark W. Chase. 2006. "Phylogeny, genome size, and chromosome evolution of Asparagales". Aliso 22(Monocots: Comparative Biology and Evolution):287-304. ISSN 0065-6275.
  4. Knud Rahn. 1998. "Themidaceae" pages 436-441. In: Klaus Kubitzki (general editor) with Klaus Kubitzki, Herbert F.J. Huber, Paula J. Rudall, Peter F. Stevens, and Thomas Stützel (volume editors). The Families and Genera of Vascular Plants volume III. Springer-Verlag: Berlin;Heidelberg, Germany. ISBN 978-3-540-64060-8
  5. Pires, J. Chris; Fay, Michael F.; Davis, Warren S.; Hufford, Larry; Rova, Johan; Chase, Mark W.; Sytsma, Kenneth J. (2001). "Molecular and morphological phylogenetic analyses of Themidaceae (Asparagales)". Kew Bulletin. 56 (3): 601–626. doi:10.2307/4117686.
  6. Flora of North America Editorial Committee. 2002. Flora of North America volume 26:321-347. Oxford University Press. ISBN 978-0-19-515208-1. see External links below.
  7. Anthony Huxley, Mark Griffiths, and Margot Levy (1992). The New Royal Horticultural Society Dictionary of Gardening. The Macmillan Press,Limited: London. The Stockton Press: New York. ISBN 978-0-333-47494-5 (set).
  8. Armen L. Takhtajan (Takhtadzhian). Flowering Plants second edition (2009). Springer Science+Business Media. ISBN 978-1-4020-9608-2.
  9. Rolf M.T. Dahlgren, H. Trevor Clifford, and Peter F. Yeo. 1985. The Families of the Monocotyledons. Springer-Verlag: Berlin, Heidelberg, New York, Tokyo. ISBN 978-3-540-13655-2. ISBN 978-0-387-13655-4.
  10. Michael F. Fay and Mark W. Chase. 1996. "Resurrection of Themidaceae for the Brodiaea alliance, and recircumscription of Alliaceae, Amaryllidaceae, and Agapanthoideae". Taxon 45(3):441-451. (see External links below).
  11. Richard Salisbury. 1866. The Genera of Plants. A Fragment Containing Part of Liriogamae:84. John van Voorst: Paternoster Row, London, England. (see External links below).
  12. Sereno Watson. 1879. "Revision of the North American Liliaceae". In: Proceedings of the American Academy of Arts and Sciences 14:238. (see External links below).
  13. Edward Lee Greene. 1886. "Some Genera Which have been Confused Under the Name Brodiaea". In: Bulletin of the California Academy of Sciences 2(6):142. (see External links below).

Bibliography
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