8 ■ A MANUAL OF MOSSES 



collector, and the date of the collection. If material has been 

 collected in sets for distribution the label should so state and 

 a number should be assigned to the various species so that 

 duplicate specimens reaching different botanists may be 

 definitely correlated. It is often advisable to add to the label 

 also the name of the botanist who identified the specimen, 

 especially if he be a specialist. 



For any extended study of the mosses, either Sphagnales 

 or Bryales, it is practically necessary to have at hand besides 

 a. pocket lens of some sort, a dissecting lens and a compound 

 microscope. A dissecting lens may be rigged up by providing 

 some sort of a frame for holding the ordinary pocket lens at 

 the right distance above the table. This can he done by some 

 such simple contrivance as knitting needles and corks, in the 

 absence of anything better. The writer has found very satis- 

 factory the ordinary dissecting stand, which may be obtained 

 from any dealer in scientific apparatus, the stand preferably 

 fitted with a rack-and-pinion adjustment for focussing the 

 lens. The writer has used with good results a doublet 

 lens (three-quarter inch) magnifying about four diameters 

 and a one-fourth inch aplanat lens magnifying about seven 

 diameters. The compound microscope should be fitted with a 

 one-inch and also preferably a two-inch eye-piece and the cus- 

 tomary two-thirds and one-sixth objectives. A sub-stage 

 condenser is a great convenience and should be provided with 

 diaphragms both above and below. 



In preparing a moss for microscopic study the writer pro- 

 ceeds as follows : A portion of the specimen, usually consisting 

 of a whole plant, is selected and is soaked in water until it is 

 soft and relaxed. A thin square of mica an inch or more in 

 width is prepared and placed on an ordinary glass microscope 

 slide, and upon it is placed a drop of a ten per cent, solution 

 of glycerine in water which is kept already prepared in a 

 small bottle with a medicine dropper fastened into the stopper. 

 The glass slide with the mica square and solution in position 

 are placed on the stand of the dissecting microscope. With 

 small forceps and with the aid of needles mounted in wooden 

 handles the moss is now carefully dissected and the parts suit- 

 ably disposed on the mica square in the film of ten per cent, 

 glycerine. It is usually best to place on the mica square some 

 thin cross-sections of the stem of the moss, cut with a 

 scalpel or knife or fine scissors, some stem-leaves, some 

 branch-leaves, some perichsetial leaves or, better, the whole 

 perichaetium dissected apart but not widely scattered, and then 

 the capsule so dissected as to show a patch of the epidermis 

 from the base of the capsule, the annulus, the peristome, both 

 outer and inner if they are present, and the spores. 



