bulletin 39, united states national museum. [20] 

 Cryptogamous Plants. 



MOSSES AND LIVERWORTS (BRYOPHYTA). 



MOSSES.* 



To collect mosses well oae ought, to have first made a study of their 

 structure. However, an intelligent and enthusiastic collector will be 

 able to distinguish between good and useless material, and to find rare 

 species, even without such previous training. 



First, then, learn to look for mosses in fruit. Most of the common 

 species have the small capsules, which contain the spores, raised on 

 slender pedicels, or setse ; other species, and these are more rare, have 

 the capsules " immersed," that is concealed among the leaves. And it 

 requires a more experienced eye to find such in the right condition. 

 Eipe fruit is desired, since only in such the delicate fringes around the 

 mouth of the capsule, and called the " peristome," are developed enough 

 for study. But if the capsule is too ripe it loses its " lid " and " calyp- 

 tra," two little cap-like bodies fitting into each other and covering its 

 upper part and mouth. Some species need to be collected at two dif- 

 ferent periods to secure all these parts. Mosses are useless for study 

 if the capsules are either too green or too old and weather beaten. 



Some mosses are dioecious, that is, the two sexes grow in separate 

 patches, either near each other, or quite apart. And since it is not pos- 

 sible for one not a student of mosses to determine whether a sterile sod 

 consists really of male plants belonging to a fruiting species near by, 

 it may be best that every thing looking like a moss be included in the 

 collection. However, unless there is plenty ot time, the collectcr will 

 do well to restrict himself to mosses with well-matured fruit. 



Second, where do mosses grow? At first the collector will see only 

 the larger common mosses. But gradually his eye becomes trained to 

 see the smaller plants, and to discern those with immersed capsules. 

 Every green patch is subjected to scrutinj^ Mosses will be found to 

 grow where none had been suspected : on a shady wall, moist precipice, 

 a weathered bowlder, an old stump or fallen log, the trunk of a tree, a 

 clay bank — even on the driest sandy prairie these little plants are found 



Third, how shall the mosses when found be collected and cared for? 

 Some species grow in dense cushions. These it is best to separate from 

 the soil and then cut into perpendicular slices in the direction of the up- 

 right stems. Or, after removing the soil and rubbish, the sod may be 

 separated into slices with the fingers. The plants thus prepared are 

 put away into paper pockets, which are conveniently folded before 

 starting on the trip. 



Other mosses grow in dense tangled mats. If time permits, these 

 should be taken up, the fruit-bearing plants picked out and put away 

 in pockets. So should all small mosses from clay banks, bowlders, or 



* By John M. Holzinger, assistant botanist, U. S. Department of Agricnlture. 



