Factoid

[Thomas G. Lammers]

At 12:28 PM 01-23-98 -0300, Doug Yanega wrote:

>I could swear I've heard that some mistletoes fired their seeds tens of
>meters, and that they were coated with a glue-like substance so they would
>stick where they hit. That would imply a pretty high velocity. I doubt the
>coiled-spring pods of legumes like Lathyrus generate quite 60 mph shots,
>and definitely not pods like Oxalis or Impatiens.

Explosive dehiscence is not uncommon in fruits, but usually it involves loss
of turgor in  the pericarp to create tension that catapults the seeds in
some fashion, i.e., the seeds are expelled dry, or at most with the
mucilaginouis coating mentioned above.  The unusual aspect of Ecballium is
the fact the seeds are dispersed explosively in a fluid medium.

I suppose one would measure it with high speed photography -- timing exactly
how long it takes to reach a given distance.  =20


Thomas G. Lammers
  =20
Classification, Nomenclature, Phylogeny and Biogeography
of the Campanulaceae, s. lat.
                                   =20
Department of Botany                            =20
Field Museum of Natural History =09
Roosevelt Road at Lake Shore Drive      =20
Chicago, Illinois 60605-2496 USA

e-mail:    tlammers at fmnh.org
voice mail: 312-922-9410 ext. 317
fax:                312-427-2530

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