[R-sig-eco] Plant biomass

[john polo]

Hello,
I have biomass measurements of plant functional groups that range from 
.002 g to 2000 g, with quite a few zeros in two of the groups as well. 
While trying to analyze this data, the negative binomial distribution 
was suggested for describing the data, with zero inflation for the 2 
groups. However, negative binomial doesn't allow for non-integer values. 
I have two questions, the first of which is, is negative binomial the 
appropriate distribution to use for this range of masses with several 
zeros? Contingent on negative binomial being the appropriate 
distribution, how do I correct for non-integer values of my masses?
Best regards,
John Polo