Burmanniaceae is a

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Ideal ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek language, Greek words ('container, vessel') and ('seed'), and refers to ...

s, consisting of 99 species of

herbaceous plant Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials. Definitions of "herb" and "herbaceous" The fourth edition of ...

s in eight genera.

Description

These plants are annual or perennial herbs, with generally unbranched stems, some lacking leaves. Some members of this family lack chlorophyll and are mycotrophic (also called

myco-heterotrophic Myco-heterotrophy (from Greek μύκης , "fungus", ἕτερος ', "another", "different" and τροφή ', "nutrition") is a symbiotic relationship between certain kinds of plants and fungi, in which the plant gets all or part of its food fro ...

). The family tends to be

saprophytic Saprotrophic nutrition or lysotrophic nutrition is a process of chemoheterotrophic extracellular digestion involved in the processing of decayed (dead or waste) organic matter. It occurs in saprotrophs, and is most often associated with fungi ( ...

and even the autotrophic species are all endomycorrhizal and probably at least hemisaprophytic. The family occurs worldwide, with a mostly tropic to subtropical distribution. A number of species are threatened.

Taxonomy

John Lindley John Lindley FRS (5 February 1799 – 1 November 1865) was an English botanist, gardener and orchidologist. Early years Born in Catton, near Norwich, England, John Lindley was one of four children of George and Mary Lindley. George Lindley ...

described the family as Burmanniae, with the single genus ''Burmannia'', in 1830. In 1998 the APG I system placed Burmanniaceae as one of five families in the order

Dioscoreales The Dioscoreales are an order of monocotyledonous flowering plants in modern classification systems, such as the Angiosperm Phylogeny Group and the Angiosperm Phylogeny Web. Within the monocots Dioscoreales are grouped in the lilioid monocot ...

, within the

monocot Monocotyledons (), commonly referred to as monocots, (Lilianae ''sensu'' Chase & Reveal) are grass and grass-like flowering plants (angiosperms), the seeds of which typically contain only one embryonic leaf, or cotyledon. They constitute one of t ...

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

. The

APG II system The APG II system (Angiosperm Phylogeny Group II system) of plant classification is the second, now obsolete, version of a modern, mostly molecular-based, system of plant taxonomy that was published in April 2003 by the Angiosperm Phylogeny Gr ...

of 2003, as a result of an extensive study by Caddick and colleagues (2002), using an analysis of three

genes In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ...

, ''rbc''L, ''atp''B and 18S rDNA, in addition to morphological criteria, led to a considerable rearrangement of the families within Dioscoreales. In APG II the

circumscription Circumscription may refer to: *Circumscribed circle *Circumscription (logic) *Circumscription (taxonomy) * Circumscription theory, a theory about the origins of the political state in the history of human evolution proposed by the American anthrop ...

of the family was wider and included the plants that belonged to the family Thismiaceae in APG I. The result was an order with only three families.

APG III APG is an abbreviation with several different meanings: * Aberdeen Proving Ground, a United States Army installation in Aberdeen, Maryland, also ** Phillips Army Airfield, the airfield of the above, from its IATA airport code * Aboriginal Provision ...

(2009) left this arrangement unchanged. Nevertheless, some ongoing research has challenged this relationship claiming that the older classification better reflects the evolutionary relationships between the genera. According to these researchers the constituent clades are as follows: Burmanniaceae ''sensu stricto'' *'' Apteria'' *'' Burmannia'' *'' Campylosiphon'' *'' Cymbocarpa'' *'' Dictyostega'' *''

Gymnosiphon ''Gymnosiphon'' (yellowseed) is a genus of monocotyledonous flowering plants from the yam order. Like most of the other members of the family in which the plant is placed ( Burmanniaceae), ''Gymnosiphon'' is entirely myco-heterotrophic genus th ...

'' *'' Hexapterella'' *'' Marthella'' *'' Mierisella'' ''Afrothismia'' clade *'' Afrothismia'' Tribe Thismieae * '' Haplothismia'' * '' Oxygyne'' * '' Thismia'' * '' Tiputinia'' But because of conflicting evidence, the

APG IV The APG IV system of flowering plant classification is the fourth version of a modern, mostly molecular-based, system of plant taxonomy for flowering plants (angiosperms) being developed by the Angiosperm Phylogeny Group (APG). It was published ...

(2016) authors felt it was still premature to propose a restructuring of the order since the most recent evidence upholds the APG configuration and the work of Caddick and colleagues.

Evolution

According to molecular analyses, the myco-heterotrophic type of life that these species lead evolved six (or even more) times independently in the three clades that are part of Burmanniaceae. '' Afrothismia'' and tribe Thismieae represent two of these shifts to myco-heterotrophy from autotrophy while Burmanniaceae ''sensu stricto'' are the clade where the other four took place. The family appears in the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', t ...

but the further diversification and shifts to the typical habit occurred later in the same period and continued after the K-T boundary in

Paleogene The Paleogene ( ; also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period million years ago ( Mya) to the beginning o ...

References

Bibliography

* * * * * * * * * , In *

APG

* * * *

External links

* *
Burmanniaceae
in L. Watson and M.J. Dallwitz (1992 onwards).
The families of flowering plants
descriptions, illustrations, identification, information retrieval.'' Version: 9 March 2006. https://web.archive.org/web/20070103200438/http://delta-intkey.com/
''Monocot families'' (USDA)

Burmanniaceae in the ''Flora of North America''

''Burmanniaceae.org, a site dedicated to the research on this family''

NCBI Taxonomy Browser

links
and more
links
at CSDL, Texas {{Authority control Monocot families Santonian first appearances Extant Santonian first appearances