66 
2 
ajerin a genus cover as you have been doing. This method 
will be well enogh for you herbarium set that we call the 
Powell collection. Of course I intend to add to that coiie® 
tion the new material you send up, out I suggest that 
you establish a separate set of numbers for the material _ 
collected in the field under the new plan. I would suggest 
that you start a new aeries of numbers beginning with 
3000. It is douotful if you will ever get to that number 
in your garden set. A number will consist of all the mat- 
erial collected in one spot that is mane into specimens 
or of all the parts of a large plant that is divided to 
make several specimens. The same number must not be used 
again even if the species has been collected before . This 
method differs from your garden system in which all the 
plants of the same species bear the same number. I hopB 
you understand the difference, because we must adhere to 
the methods that govern field work the world over. 
Bead carefu lly pages 157 to 161 in Willis's flowering 
plants a n d fe r ns. 
Another press was sont to you some days ago together 
with additional papers for drying. These presses should 
be tahen into the field and the plants placed directly in 
