INTRODUCTION TO CRYPTOGAMIC BOTANY. 503 



Several species of Omalla occur in New Zealand, and two of 

 Nechera, of which one, N. pennata, a species which occurs 

 sparingly in Great Britain, is almost cosmopolitan. There 

 is no species in the Antarctic Flora. Trachyloma is dis- 

 tinguished by its dendroid habit, and the leaves not being 

 oblique. The ramification is pinnate, which separates it from 

 Climacium, in addition to the absence of lacunose cilia. 

 N'eckera is a genus of hot countries, and abounds in India and 

 the hotter parts of South America. A few species only occur 

 at once in the Old and New World. 



8. Hypnei, Br. c& Sc, Mont 



Stems mostly imbricated and cylindrical ; sporangium cer- 

 nuous ; peduncle elongated ; peristome double ; calyptra dimi- 

 diate. 



562. After the genus Hypnum has been cleared of the 

 species with erect perithecia, and of a few others differing 

 strikingly in habit, there remains a vast mass of species dis- 

 tributed widely over the world, of which nearly one hundred 

 occur in England alone. They vary immensely in size, and 

 are divisible into several sub-genera ; but a little experience 

 at once separates true Hypnei from all extraneous mosses. 

 Trees, rocks, and dry or shady banks, abound with them. The 

 stems are for the most part creeping, but are branched so as 

 to make thick tufts. Occasionally the branches are pinnate, 

 but even then they are easily distinguished from Neckera by 

 their cernuous sporangia. The species are monoecious or 

 dioecious, and in the latter case the fruit is often extremely 

 rare. In a few species only the stems are flattened and the 

 leaves distichous ; in many, however, they are secund without 

 any flattening of the stem. The modifications of the leaves, 

 peduncle, calyptra, peristome, &c., are almost infinite, and 

 must be studied in detail. One or two exotic genera also 

 occur, of which it is needless to state the peculiarities in this 

 place. 



9. Leucodontei, Br. tO Sc. Isotheciis, Br. & Sc, inclusis. 

 Stems cylindrical ; leaves imbricated ; areolae small ; spo- 

 rangia erect ; peristome single or double ; calyptra dimidiate. 



563. The cuculliform calyptra distinguishes these plants 



