36 THE HABIT AND THE HABITAT OF FERNS [CH. 



their leaves, together with divaricating pinnae. This is the case with Glei- 

 chenia, in which the leaf grows intermittently at its apex, the details varying 

 greatly with the species. After forming one or more pairs of pinnae the 



Fig. 41. Trichomaiies aiiricitlatum, a stem-climber from Northern India. 

 {\ size. After Christ.) 



circinate tip becomes dormant, and the pinnae enlarging give the misleading 

 appearance of a dichotomy. In a fresh season its activity is renewed, and 

 fresh pinnae are formed. This may be continued indefinitely. As the pinnae 

 and often also the pinnules may repeat the process, the leaf with its wide- 



