insecticides used in herbaria

Richard Jensen rjensen at SAINTMARYS.EDU
Wed Feb 2 12:16:26 CST 2005

If you Google the following, "mercuric chloride" herbarium, (use the quotes) you'll find several links, including one to SPNHC, that address mercuric chloride as well as other pesticides.


Gayle wrote:

> Dear Taxacom members,
> I have been going through old herbarium specimens (circa 1800's) borrowed from some prominent old herbaria.  Some of the specimens (algal) are coated with a black powdery substance and the paper is browned and disintegrating.  When I first pulled the specimens from their cabinets (some that hadn't been opened in many years), the toxic smell in the cabinets was pretty overwhelming.  Now that the specimens have been in boxes outside the cabinets, they no longer smell but some still have this powdery substance on them.
> My question is:  What insecticides have been used by herbaria in the past?  Can people be affected by these toxins by smelling or touching them?  Do these toxins break down in time so that older herbarium specimens are safe?  If they are toxic, are there antidotes or safety measures for looking at these specimens?
> Sincerely,
> Gayle Hansen
> Hatfield Marine Science Center
> Newport, Oregon
> gayle.hansen at

Richard J. Jensen              | tel: 574-284-4674
Department of Biology      | fax: 574-284-4716
Saint Mary's College         | e-mail: rjensen at
Notre Dame, IN 46556    |

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