222 FLORA OF WASHINGTON AND VICINITY. • 



losing plants and having them turn up in an injured condition among 

 the wet papers. 



The differences in the nature of plants will render some additional 

 precautions sometimes necessary. It is often well after the first chang- 

 ing to group into one place all the thick-stemmed specimens and give 

 them more driers, or to group all the grasses, rushes, etc., by themselves, 

 give them fewer driers, and perhaps change them less often. Some 

 kinds of plants can with diflBculty be pressed at all, and must be for the 

 most part dried out between papers with scarcely any pressure. This 

 is the best way with Opuntia, Sedum, Portulaea, etc. Others, like 

 Cynthia Dandelion, are so full of juice that very light pressure seems to 

 disintegrate the structure and turn the specimens blaclv. There are a 

 few plants, such as Gerardia^ Buchnera, Herpestis, and Bapfina, which 

 are said by the books to "turn black in drying," as though this would 

 occur whatever plan might be adopted. To some extent this is true, 

 and yet by the above method I have dried all these plants so that the 

 green color largely predominates in the dried specimen. 



I cannot advise the purchase of patent kinds of drying paper. I have 

 tried the best of them, and, independently of cost, I prefer the straw 

 paper. I have also heard other experienced botanists make the same 

 admission. Simplicity and convenience are important objects to aim at, 

 and for most botanists economy is equally so. 



The drying of damp papers is always considerable trouble, and various 

 devices for hanging them up on frames or "horses" built for the pur- 

 pose hav^e been used. These are well, but beginners will scarcely have 

 them, and must resort to other methods. If you have a lawn, and the 

 weather is fine, it is best to spread them out in the sun, where they will 

 dry immediately. The thin brown papers here recommended dry much 

 quicker than the thicker kinds sold, and if the pains are taken to open 

 them entirely out, the process is still further hastened. If you have 

 only in-door facilities, the papers may be spread out over the tables, 

 chairs, and floor, where they will usually dry in a night or a day. It is 

 a good plan to heat them in an oven after picking them up and before 

 using. In throwing them down they will dry faster if no effort is made 

 to lay them in any systematic way, and no evils need be feared from 

 their becoming rolled up and wrinkled, as this only increases the sur- 

 face for the access of the air. They should, however, be picked up sys- 

 tematically, keeping the ends even ; otherwise, they will consume much 

 time when needed for rapid use, where thej^ must often be picked up 

 with one hand while the other is doing something else. 



