36 MOSSES WITH A HAND-LENS 



THE HYPNUM FAMILY 



THE two preceding species belong to the great Hypnum 

 Family, which contains a vast number of our common 

 mosses. The majority of the members of this family are 

 slender and prostrate, or creeping with ascending branches. The 

 sporophyte varies a good deal, but the capsules are more or less 

 unsymmetric and cernuous in most species. The members of 

 this family usually grow in dense thin mats on soil, stones, rotten 

 wood, and bark of trees. There are hundreds of species belong- 

 ing to this family and the number within our own range is very 

 large. Many of the species and even genera are so closely re- 

 lated and are distinguished by so few and so minute differences 

 that no one but a trained and expert student of mosses can name 

 them correctly. For this reason only a few of the most strongly 

 marked species can be treated here. This is to be regretted, for 

 many of the commonest mosses will thus be omitted and the 

 student will be discouraged by finding so many things that he 

 cannot identify. It is safe advice to the beginner to leave the 

 Hypnums until he has studied the more easily recognized mosses. 

 Roughly, the more common genera are distinguished thus: 

 Plagiothecium and Entodon are flattened in a plane parallel to 

 the substratum, but the capsules of Entodon are erect and sym- 

 metric, while those of Plagiothecium are curved and cernuous. 

 Brachythecium has very short ovoidal capsules that are cernuous 

 and somewhat curved (except B. acuminatum and B. oxycladon); 

 the leaves have a strong midrib. Eurhynchiuin, Cirrpihyllutn, 

 and Rhynchostegium have the strong midrib and short capsules 

 of Brachythecium, but the opercula are grotesquely long-beaked, 

 much as in Dicranum. Raphidostegium has long-beaked cap- 

 sules like the three genera mentioned above, but the leaves lack 

 the midrib. Pylaisiella grows exclusively on the bark of trees, and 

 is dark green ; the short branches are strongly curved at the end 

 when dry, and the capsules are erect and symmetric. Hypnum 

 has so many varying forms that one can best get an idea of it 

 from studying the individual species described below. 



HYPNUM 



In one section of this composite genus the leaves are all 

 turned to one side (secund), and the branching is more or less 

 regularly pinnate, giving the plants a plume-like appearance in 

 many cases. The leaves are without midrib. This section is 



