''Smilax'' sect. ''Nemexia'' is a

section Section, Sectioning or Sectioned may refer to: Arts, entertainment and media * Section (music), a complete, but not independent, musical idea * Section (typography), a subdivision, especially of a chapter, in books and documents ** Section sig ...

plant Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclu ...

s in the family

Smilacaceae Smilacaceae, the greenbriers, is a family of flowering plants. While they were often assigned to a more broadly defined family Liliaceae, most recent botanists have accepted the two as distinct families, diverging around 55 million years ago dur ...

. It consists of the herbaceous plants within the genus ''

Smilax ''Smilax'' is a genus of about 300–350 species, found in the tropics and subtropics worldwide. In China for example about 80 are found (39 of which are endemic), while there are 20 in North America north of Mexico. They are climbing flowering ...

''. ''Smilax'' species fall into two groups with distinctive morphologies: one group has woody

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wid ...

stems with thorns and a vining habit, while the other group has herbaceous stems that die back to the ground each winter. ''S.'' sect. ''Nemexia'' is the

taxon In biology, a taxon ( back-formation from '' taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular n ...

that comprises the herbaceous species. In the past it was often a genus of its own under the name ''Nemexia'' and taxonomists still need further study of the species of ''Smilax'' to determine its proper rank.Fu, C., H. Kong, Y. Qiu, K. M. Cameron. 2005
Molecular phylogeny of the East Asian-North American disjunct ''Smilax'' sect. ''Nemexia'' (Smilacaceae).
''International Journal of Plant Sciences'', 166(2): 301-309. However the widely accepted taxonomic system of the '' Flora of North America'' does not recognize ''Nemexia'', nor does th
AP-site
Thus ''Nemexia'' is not currently considered an accepted genus

by most plant taxonomists.ISB: Atlas of Florida Vascular Plants
/ref> The plants in ''Smilax'', are called

carrion flower Carrion flowers, also known as corpse flowers or stinking flowers, are mimetic flowers that emit an odor that smells like rotting flesh. Apart from the scent, carrion flowers often display additional characteristics that contribute to the mimes ...

s for their malodorous

flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...

s and those plants included in section ''Nemexia'' also have flowers that smell like rotten meat. The herbaceous species have greenish-yellow flowers and bloom in spring, they are fly pollinated.

Phylogenetic relationships

Cladistic analysis among several members of the section was carried out in 2005 on several gene sequences, including the plastid ''trnL-F'' and ''rpl16'' sequences and the nuclear

internal transcribed spacer Internal transcribed spacer (ITS) is the spacer DNA situated between the small-subunit ribosomal RNA (rRNA) and large-subunit rRNA genes in the chromosome or the corresponding transcribed region in the polycistronic rRNA precursor transcript. I ...

. The eastern North American species in the morphologically variable ''S. herbacea'' complex form a sister group to the western North American ''S. jamesii''. The analysis did not conclusively clarify whether the ''S. herbacea'' complex should be recognized as different species. The two East Asian species, ''S. riparia'' and ''S. nipponica'', formed two well-defined clades. It is hypothesized that the ancestor of this section evolved in Asia and spread to North America via the Bering Strait land bridge.

References

External links

:
Smilacaceae
in L. Watson and M.J. Dallwitz (1992 onwards).
The families of flowering plants
descriptions, illustrations, identification, information retrieval.'' Version: 9 March 2006. http://delta-intkey.com. :
Smilacaceae in ''Flora of North America''
:
links at CSDL, Texas
The current entry states "The two East Asian species, S. riparia and S. nipponica, formed two well-defined clades." But according to the abstract of reference 2 (Fu et al. 2005) "Results strongly support a clade of two well-defined East Asian species, Smilax riparia and S. nipponica." Thus, the entry should read: "The two East Asian species, S. riparia and S. nipponica, formed a clade." {{Taxonbar, from=Q3338007 Smilacaceae Plant sections