24 A FLORA OP MANILA 



THE HERBARIU»£ 



A collection of dried plants is called an herbarium, and such a collection 

 is most essential in the study of taxonomy or systematic botany. 



For convenience in referring to , specimens, the dried plants are com- 

 monly mounted on sheets of fairly stiff white paper, the usual size, known 

 as the standard herbarium sheet, being 29 by 42 cm. Any paper of good 

 quality and fairly stiff can be used, but about 60-pound linen ledger paper 

 is best adapted to all purposes. 



There are several methods of mounting specimens, the chief being a 

 combination of gumming and strapping, or strapping alone. Ordinary glue, 

 fish-glue, or mucilage, can be used in fastening specimens to the herbarium 

 sheets, but the most satisfactory adhesive is gum arable dissolved in cold 

 water to the consistency of ordinary mucilage; to this mixture a small 

 amount of carbolic acid should be added to keep it from souring. The 

 form of gum arabic known as powdered acacia is the most convenient for 

 general use, as it dissolves very quickly. 



With gum arabic solution one can make his own gummed paper, for 

 strapping plants, by taking any tough white paper and with a soft brush 

 painting over one side with the gum arabic solution and allowing it to 

 dry. It can then be cut into strips of various widths and used as desired. 



In gumming plants a thin layer of the gum is spread out on a smooth 

 hard surface by means of a brush. The plant to be mounted is then placed 

 on this gummed surface and all parts are gently pressed down so that the 

 gum is evenly distributed over the lower surface of the specimen; it is 

 then carefully removed and transferred to the mounting paper in the 

 position desired and the sheet placed between driers under light pressure 

 until thoroughly dry. Later the heavier parts, such as the stems, ends of 

 leaves, etc., are more firmly fastened by the use of narrow strips of 

 gummed paper. This method is the best one for a collection that is to be 

 consulted or studied a great deal. 



Another general method is to lay the plant on the mounting paper in 

 the position desired and firmly fasten it in place by the use of strips of 

 gummed paper, without previously fastening the plant to the paper by 

 gumming as described above. The advantage of this method is that the 

 entire plant can, if necessary; be removed for purposes of study, which 

 is impracticable when the specimens are gummed. Plants can be mounted 

 without the use of gum by folding strips of paper about the stems and 

 other coarse parts, and pinning the ends of the paper strips to the 

 herbarium sheet. 



In mounting specimens the leaves should be so arranged that both 

 surfaces are shovra. Detached flowers, fruits, small leaves, etc., are best 

 preserved by placing them in small envelopes or packets whicli are attached 

 to the sheet. Mosses, scale-mosses, most fungi, lichens, etc., can be pre- 

 served in packets which should be attached to herbarium sheets. Only one 

 species should be mounted on a single sheet, but several specimens of the 

 same species showing variation etc., can be attached to the same sheet. 



The name of the plant, genus and species, locality, collector, and date 

 of collection should be written on the lower right-hand corner of the sheet, 

 or on a label attached to the sheet; sometimes other data are added but 

 these additional data are best preserved on the field label which may be 

 attached to either the upper or lower left-hand corner of the sheet. 

 Herbarium labels are usually about 6 by 12 cm, and should be printed on 

 paper of good quality. 



