THE HERBARIUM. 383 



inches is a nuisance ; and those of an inch and a quarter or an 

 inch and a half in width and three or four inches in length are 

 most commodious. 



813. The sheets of all the species of the same genus, when 

 not too numerous, or of a particular section of it, or any conven- 

 ient number, should be consigned to one genus-cover. The best 

 genus-covers are of manilla-rope paper, the " bleached manilla " 

 such as that of which tags are made is the neatest article, but 

 rather more expensive : they are in whole or folded sheets (pref- 

 erably in quarter quires), accurately trimmed at top, bottom, 

 and front edge to the size of 16 i by 11 inches; that is, the 

 folded sheet as used is a trifle longer and a quarter of an inch 

 wider than the species-sheets it holds. The sheets to be firm 

 enough should weigh H or If ounces each, or from 45 to 52 

 pounds the ream. The generic name should be written in a bold 

 hand on the lower left-hand corner ; that is, on the upper face next 

 the back : at or near the lower right-hand corner, the name of the 

 contained species may be written either with a pencil or in ink. 



814. The genera should be arranged in the herbarium accord- 

 ing to some systematic work, and numbered accordingly on the 

 covers. 



815. The herbarium must be preserved in close cabinets or 

 cases free from the access of dust. Tin cases, just deep and 

 wide enough to receive comfortably the genus-covers, and about 

 six inches high, the hinged lid being one end, may be recom- 

 mended for a small collection, as they are dust and insect 

 proof, are portable, and may readily be arranged on shelves. 

 But, for any herbarium of considerable size and continued growth, 

 wooden cabinets with well-fitted doors are to be preferred ; the 

 interior of the cabinets being divided into pigeon-hole compart- 

 ments, fully 12 inches wide in the clear and 17 inches deep, and 

 not over 6 inches or in small herbaria not over 4 inches high. 

 Into such pigeon-holes, the genus-covers with their contents will 

 slide readily, and may be compactly stowed awa}-. An index 

 to the genera of each order may be affixed to the interior of the 

 cabinet doors, or pasted upon the upper face of thin boards, 

 inserted at the beginning of each order. The name of the order, 

 written or printed in bold letters, may be pasted upon the front 

 edge of this board, or upon a flap of card-board affixed to it. 

 Moreover, it is well to write the name of the order upon each 

 genus-cover. 



816. Except in public collections, where fixed cases may be 

 preferred, the cabinets should individually be small, only three 

 or four feet high, and containing only two or four vertical rows 



