Nice writeup. Best of luck Ritesh. Pankaj On Friday, 25 April 2014 12:53:29 UTC+8, Ritesh Kumar Choudhary wrote: > > Family of the fortnight: POLYGONACEAE > > Distribution: The family includes approximately 46 genera and 1200 species > (Mabberley, 2008) from the world and mostly distributed in north temperate > regions. > > Two subfamilies Polygonoideae and Eriogonoideae are universally accepted > based on the presence or absence of the ochrea (sometimes rudimentary in > Eriogonoideae). > > > All Indian genera belong to Polygonoideae, a subfamily of almost 790 > species defined by the presence of ocreae, a monopodial branching pattern, > and lack of involucre. > > The Eriogonoideae (ca. 330 species) are found only in the New World. (Li > Anjen et al., 2003). > > Description: Members of Polygonaceae are either annual or perennial > herbs, shrubs or trees. The leaves are simple, alternate, seldom opposite > or whorled, usually entire and revolute, usually in spirals, petiolate to > sessile. > > The presence of ochrea is the most distinguishing feature, but in the > subfamily Eriogonoideae, it is either absent or reduced in size. > > Variation can be seen in the axillary or terminal inflorescence which is > composed of simple or branched thyrsi panicle-, raceme- or spike-like in > appearance which however, are formed of dichasia or helicoid cymes. > > The flowers are small, trimerous, hermaphrodite or unisexual with tepals > 2-6, forming two whorls of 3 elements or one whorl of 5 elements with > characteristic quincuncial aestivation. > > The number of stamens ranges from 2 to 9 or rarely more whereas the pollen > character varies from tricolporate to pantoporate. The ovary is superior > 2-4 carpellate (generally 3-carpellate) and unilocular whereas the fruits > are an achene which is trigonous or lenticular. > > > Taxonomic treatments: > > Recently, Sanchez et al. (2011) proposed a new taxonomic classification > for Polygonoideae based on molecular data that includes five tribes: > Calligoneae, Fagopyreae, Persicarieae, Polygoneae, and Rumiceae. > > Polygonum s.l. is the largest genus in Polygonaceae and a member of the > core eudicots in the flowering plants (Judd et al. 2002). It is > represented by about 230 species in the world and distributed mostly in N > temperate regions (Li Anjen et al, 2003). The genus (commonly known as > Knotweeds) has long been a taxonomic puzzle and is widely debated. > > The traditional method of classification has led to disagreement among > taxonomists with regard to which species should be included in the genus > *Polygonum > *and which taxa should be elevated to their own genus due to the presence > of at least one distinguishing characteristic. (Meisner, 1826, 1856, 1857; > Bentham & Hooker, 1880; Dammer, 1892; Gross, 1913 a, 1913b; Jaretzky, 1925; > Hedberg, 1946; Roberty & Vautier, 1964; Graham & Wood, 1965; Holub, 1971; > Sojak, 1974; Haraldson, 1978; Tzvelev, 1987; Ronse Decraene & Akeroyd, > 1988; Hassan, 1991, 1997; Hassan & Khan, 1992; Hong et al, 1998; Ronse > Decraene et al., 2000). > > The biomolecular studies by Cuenound et al. (2002), Lamb Frye & Kron > (2003), Kim et al. (2005), Kim & Donoghue (2008) and Sanchez and Kron > (2008) have revealed that *Polygonum *s.l. is polyphyletic, and should be > divided into several genera. The treatment of subfamily Polygonoideae by > Haraldson (1978) Ronse Decraene (1988) have suggested species of *Polygonum > *in the broad sense to be segregated into two separate tribes, Polygoneae > and Persicarieae. > > Medicinal Value: > Medicinal uses of 31 species belonging to 7 genera Viz. *Calligonium*, > *Pteropyrum*, *Polygonum*, *Fagopyrum*, *Rheum*, *Oxyria* and *Rumex*, > were recorded by Kirtikar & Basu (1980). > > Thirty four species of *Polygonum* (*s.l.*) have been reported for > medicinal uses (Choudhary et al., 2011). > > Some useful references: > > http://www.ingentaconnect.com/content/iapt/tax/2011/00000060/00000001/art00013 > http://flora.huh.harvard.edu/china/mss/volume05/Polygonaceae.pdf > http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=10717 > http://donoghuelab.yale.edu/sites/default/files/174_kim_systbot08_0.pdf > > http://lnmcp.mf.uni-lj.si/Fago/Fagopyrum/Fagopyrum/Each/Fag(18)/Fag(18)-9.pdf > http://archive.bsbi.org.uk/Wats5p177.pdf > > http://www.biology.sc.chula.ac.th/TNH/archives/v11_no1/21-28%20Chorthip%20TNH%2011-1.pdf > > http://www.lifesciencesite.com/lsj/life1002/369_B01505life_1002_2664_2670.pdf > > > Regards, > Ritesh. > > Note: Please write me separately for details of the references used in > the text above. > >
-- You received this message because you are subscribed to the Google Groups "efloraofindia" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/indiantreepix. For more options, visit https://groups.google.com/d/optout.
