8 American Midland Naturalist Monograph No. 6 



each specimen should be fastened to the narrow flap at the upper edge of the 

 pocket and should always contain the name of the species, the exact locality 

 and habitat of the specimen, the name of the 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 sp>ecialist. 



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 dis- 

 secting lens and a comjwund 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 be done by some such simple con- 

 trivance as knitting needles and corks, in the absence of anything better. The 

 writer has found very satisfactory 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 focusing the lens. The writer has used with 

 good results a doublet lens (three-quarter inch) magnifying about four di- 

 ameters 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 customary two-thirds and one-sixth objectives. A 

 sub-stage condenser is a great convenience and should be provided with dia- 

 phragms both above and below. 



In preparing a moss for microscopic study the writer proceeds as follows: 

 A portion of the specimen, usually consisting of a whole plant, is selected and 

 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 miscroscope 

 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 suitably 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 

 kriife or fine scissors, some stem-leaves, some branch-leaves, some perichajtial 

 leaves or, better, the whole perichaetium dissected apart but not widely scat- 

 tered, 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. 



Another thin mica square is now selected a little smaller than the first one 

 used and upon it is placed a small chunk of glycerine-jelly, which is melted 

 by holding the square in the forceps over a suitable source of heat — the writer 

 holds the square over the electric bulb of his desk light. The glycerine when 

 melted is smeared over the surface of the mica, which is then inverted and 



