The link may not work so I have copied the contents of an article related to one interesting plant we had discussed earlier. I think Pankaj Oudhia ji has more knowledge on this.
http://epaper.timesofindia.com/Default/Client.asp?Daily=TOIPU&showST=true&login=default&pub=TOI&Enter=true&Skin=TOINEW&GZ=T&AW=1305104388734
http://epaper.timesofindia.com/Default/Scripting/ArticleWin.asp?From=Archive&Source=Page&Skin=TOINEW&BaseHref=TOIPU/2011/05/11&PageLabel=2&EntityId=Ar00202&ViewMode=HTML
Dr Phadke Satish
Green group conducts DNA barcoding of Ramkand
Kalyani Sardesai TNN
Pune:
Sahyadri Genes, a Kolhapur-based environmentalcum-research group, and
the department of botany, Shivaji University, have carried out DNA
barcoding of the Ramkand plant, which, according to popular legend, was
consumed by Lord Rama while in exile.
The study, which
establishes that the plant is a monocot and not a tuber, has been
published in the recent issue of ‘Current Science’.
Speaking to TOI, Mansingraj Nimbalkar, president, Sahyadri Genes, said, “For several years, the exact identity
of Ramkand has remained a mystery for both plant researchers and
students. Though the tuber is being sold for several years, especially
at places of pilgrimage, its source is one of the best kept secrets by
vendors. The name and information provided by vendors give an impression
that the tuber was eaten by Lord Rama during his days of exile.
Previous efforts to identify the plant have proved unsuccessful. The
only material available for study are the thin slices sold by vendors.”
During the study, the team initially found it difficult to establish its identity as a monocot.
“Though the anatomical study showed a cell structure typical to the
monocot, it only confused us further. This is because, monocots have
adventitious roots and not a tap root.”
The
DNA was extracted from the slices obtained from a vendor at Jyotiba
hill temple at Wadi Ratnagiri in Kolhapur district. The slices were
approximately 4.5 inches in size and two to three mm in thickness.
The
sequence was used to find similarities with the other submitted
sequences. The search showed that the sequence was 89 per cent similar
to the Agave sisalana — a monocot.
“To confirm this further, we
checked more plants of the Agave genus. The leaves enclosing the rosette
and juvenile inflorescence (soft middle
portion of the plant) were removed, which exposed the core of the
rosette. The core was soft and similar in dimension to that of the
Ramkand plant,” said G B Dikshit, professor, department of botany,
Shivaji University.
Taxonomist S R Yadav explained the
significance of the DNA barcoding. “It is a major step forward as the
plant has proved to be difficult to place. Over the last 25 years, I
have approached leading botanists in the country to help me identify the
Ramkand, but they could not,” he said.
Moreover, the study dispels
the myth about the plant being a tuber. “The origin of the plant is
being carefully concealed by vendors, but Ramkand, which is sold to
devotees in the name of Lord Rama, is actually not recommended for human
consumption. In fact, it can prove to be poisonous,” he said.
“One
variety of the Agave genus is used to make a syrup for diabetic
patients, but, by and large, the species are not meant to be eaten.
Since it is sold in thin slices and people consume it in small
quantities, it may not have had any noticeable after-effects. But it is
important that people know the facts,” Yadav said.

The Ramkand plant