20 MISC. PUBLICATION 568, U. S. DEP'T. OF AGRICULTURE 



Commercial slat frames are usually unsatisfactory because of flimsy 

 wood, poor construction, and excessive price. They can be made easily 

 and cheaply from ash or oak strips, but any similar flexible wood will 

 serve just as well. The slats should be )4, mcn thick and about 1 inch wide. 

 Small brass screws or small brass nails, properly clinched, are best for 

 fastening the slats together, but ordinary screws or nails will serve just 

 as well. 



The ordinary botanical blotters are dark gray in color and of variable 

 quality and thickness. A medium weight is best for all purposes, but 

 regular desk blotters can be used, despite their comparative thinness. 



Ventilators are nothing more than pieces of ordinary, double-faced, 

 corrugated cardboard. In fact, cardboard cartons often can be cut down 

 to make satisfactory plant-drying material. Some commercial ventilators 

 are made of soft paper and therefore go to pieces within a short time. 



Folders usually are made from old newspapers, but most newspapers 

 are too large and need to be cut down to the desired size. The trimming 

 is done so that the folders open on the long side, not the short side (see 

 fig. 4). Newsprint sheets, measuring 23 by 33 inches, can be purchased. 

 These need to be folded. 



The lengths of sash cord are used to maintain sufficient pressure to 

 keep the plants completely flat during the drying process. To accomplish 

 this, a piece of rope is fastened around the filled press about 5 inches 

 from either end. The loose end of the cord passes through the loop, is 

 pulled tight, and is then tied with a slipknot (figs. 4, 29). Some collec- 

 tors prefer web straps for this purpose, but these are more expensive 

 than the sash cord. Furthermore, they are not available everywhere 

 and hence cannot be easily replaced when worn out, lost, or stolen. 

 On the other hand, the sash cord can be purchased nearly everywhere 

 and is not so apt to be stolen. 



Hints on Pressing 



For best results, the process of pressing and drying must begin soon 

 after the plants are collected. Four to 6 hours will allow a safe margin. 

 At least a few hours should elapse in order to let the plants wilt slightly, 

 because a limp plant can be arranged more satisfactorily for pressing. 

 Crumpled leaves can be smoothed out and some can be turned so that 

 both leaf surfaces will be visible in the dry specimen (figs. 9, 11). Some- 

 times as much as 24 hours can elapse, but much depends upon the kind 

 of plant and the climate. Some plants will collapse and spoil within a few 

 hours, especially those with delicate flowers and leaves. But grasses and 

 coarse-leafed plants may be kept several days. Hot, humid weather will 

 cause specimens to sweat and disintegrate more rapidly than cold, moist 

 conditions. 



Much time can be saved by proper arrangement of materials. If 

 no table is available, some sort of bench can usually be improvised from 

 boards and boxes. The collecting case is placed at the right so that the 

 newspaper folders open to the right. The press lies directly in front of 

 the operator, with the folders opening to the left. Separate piles of folders, 

 ventilators, and blotters are arranged to the left and to the front within 

 easy reaching distance. The permanent notebook, together with pen, 

 pencils, and other small objects, might be placed on a small table or 

 stand at the right. A small flat cardboard box makes a convenient re- 

 ceptacle for keeping smaller working tools together in one place. 



