DNA from herbarium specimens

[Lorelei Norvell]

I have been successful in extracting and amplifying nDNA (ITS1 + 5.8srRNA 
+ ITS2) from over 100 different dried herbarium specimens.  However, I 
have found that the older the DNA, the greater problems I have 
encountered.  Unfortunately it is imperative I extract DNA from type 
specimens collected from 1910 to 1970.  While I have had some success 
with the 1970 and 1956 collections, I am encountering problems with 
degraded DNA.
	I would welcome advice with respect to
[1]  Whether drying the specimens again before extraction would increase 
success or further degrade the DNA (drying with no heat).
[2]  Another procedure besides the hot CTAB procedure I have used
[3]  Any other preparation advice.

Thanks.
Lorelei Norvell
University of Washington
Department of Botany