poisonous seeds (Ricinus)

david walker david at ALEGBA.DEMON.CO.UK
Tue Mar 24 13:00:36 EST 1998

David Kramer wrote
Several sources (e.g., Magic and Medicine of Plants) report that castor
beans (Ricinus) are poisonous. Years ago at Indiana University we
dissected castor beans in general botany labs as an example of a seed in
which the endosperm is not absorbed until the time of germination ( in
contrast to garden bean, etc.). We stopped doing that when we were told
that the poison in the seeds could even be absorbed through the skin!
Before you ask students to dissect them, you might want to investigate this

Please post what you find to Plant-Ed. I often see this plant in botanical
gardens and other public plantings as an ornamental. Granted it is very
attractive but I always wonder why they would be put in a public place
where children might ingest the seeds. If someone will tell me they are
not poisonous, I'll stop worrying!

Dr. David W. Kramer
Department of Plant Biology
Ohio State University at Mansfield
1680 University Drive
Mansfield, OH 44906-1547
(419) 755-4344 FAX: (419) 755-4367
e-mail: kramer.8 at osu.edu
The seeds of Ricinus communis are extremely poisonous. As I recall, about
11 seeds are reputed to constitute a fatal dose and certainly the purified
toxalbumin (Ricin), which was used to kill the Bulgarian dissident Georgi
Markow in London,is second only to botulin in terms of toxicity. In
addition the seeds contain an allergen (famous in some botanical circles,
for its dramatic effects on those unlucky enough to be affected by it) and
a poisonous alkaloid, seemingly thrown in for good measure. Keep worrying!

David Walker

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