6 Department Circular 76, U. S. Dept. of Agriculture. 



much better specimens may be obtained. Care must be taken not to 

 immerse the flowers. Ironing such plants while in the folder with 

 a very hot flatiron has been recommended by some. Cacti with flat- 

 tened joints may be split, scraped out, and dried in the usual manner. 

 Those with round stems should be cut into transverse sections and 

 dried. 



Seeds and small fruits. — Seeds and small fruits may be put in en- 

 velopes and placed in the collecting sheets with the specimens from 

 which they were taken. Fleshy fruits, thick roots, and flesh}^ flowers 

 of considerable size should be preserved in alcohol or formaldehyde^ 

 and provided with labels, written in pencil on some nonbibulous 

 paper, which will serve to connect them with the corresponding herba- 

 rium specimens. It is ver}^ desirable that photographs of such ma- 

 terial should also be made, of natural size if possible; otherwise 

 on some definite scale, which is best shown by placing a small paper 

 with centimeters ruled on it on the background of the specimen. 



INSTRUCTIONS FOR PRESSING SPECIMENS. 



Specimens should be transferred to the press as soon as possible 

 after returning from the field, particularly in hot weather. If un- 

 avoidable they may be left over night in the portfolio, if this is 

 strapped up tightly. The collecting sheets containing the specimens 

 are laid in the press in alternation Avith the driers and strawboards in 

 the following order : Drier, collecting sheet, strawboard, and so on. 

 The press is then strapped up tightly and placed in the sun or in some 

 Avell- aired place, as before an open window. At the end of the first 

 day the specimens should be examined and the driers exchanged for 

 fresh ones, when folded leaves may be straightened and the appear- 

 ance of the specimens improved. Stems which have been bent and 

 tend to straighten out, such as those of grasses, may be secured by 

 passing the bent portions through slit strips of paper. (See fig. 2.) 

 It is important that the dried specimen should show both sides of the 

 leaves when it is mounted, and this may be attended to now, when the 

 sjjdcimens are limp after their first day in the press. The press should 

 then be tightly strapped again. In the case of ordinary specimens 

 no further change of driers is required if plenty of strawboards have 

 been used. If these are not available and driers only are used, it is 

 necessary to change the latter every day for five or six days, substitut- 

 ing each day fresh, preferably warm, sun-dried driers. Average 

 specimens will be dry in a week and thin or delicate ones, such as 

 grasses and ferns, in two or three days, while very fleshy plants will 

 require a longer period. 



1 Formaldehyde used as a preservative should have a strength of 21 per cent. This 

 may be obtained by diluting the commorcial formaldehyde, or formalin, which is of a 

 strength of 40 per (-('nt. with l.'> times its voliniK' of water. 



