Question on Thompson's seed bank database
 

Hello everybody,
maybe some of you know the seedbank database compiled by Thompson et
al (1997). I have here the electronic version of the database but at
the moment not the accompanying book. My problem is: there are 4
categories for seed longevity [1 - 4] but in all publications I have
at hand there are only three mentioned (transient, short term & long
term persistent). So, what is category 4? In one publication a
subdivision of the "transient" category is mentioned: a) germinating
at once and b) germinating at the beginning of the next growing
season. So maybe category 4 can be explained this way?
Any help very much appreciated
Judith