INTRODUCTION TO CRYPTOGAMIC BOTANY. 545 



nophyllwm is distinguished from Trichomanes by its short 

 columella and two-yalved indusium, while that of Trichomanes 

 is cupshaped, and the columella exserted. In such species as 

 T. elegans the cup seems to be entirely a development of the 

 tip of the costa, and this is probably the case generally in the 

 genus Trichomanes. Most of the species are tropical, but a 

 few are found in most parts of the world. From their filmy 

 nature, they delight in a moist atmosphere, and some require 

 constant moisture, as the spray of waterfalls, &c. Loxsoma is 

 confined to the northern parts of New Zealand, and has the 

 habit of Davallia. About a fifth of the New Zealand ferns 

 belong to this division. 



17. Cyatheace^, Kze., Presl. 



Sporangia pedicellate, suborbicular, or obovate, lenticulari- 

 compressed, surrounded by a complete or incomplete ring, 

 bursting laterally. Ai-boreous, seldom herbaceous. 



622. This tribe contains many of the finest forms, distin- 

 guished by their arboreous habit, which makes them and simi- 

 lar ferns, some fossil species excepted, the noblest represen- 

 tatives of the Cryptogamic Flora. They are, for the most part, 

 tropical, but yet, like so many others of the finest Cryptogams, 

 they are found in colder climates, provided the temperature is 

 tolerably equable, as in New Zealand and other southern isles. 

 There are species, also, at the Cape, and amongst the Hima- 

 layas. Presl remarks that the genera of Gyatheaceoe repre- 

 sent the tribes of GathetogyratcB. Cyathea and Cnemidaria* 

 answer to Pcsrawemacece; M atonia f to A spidiacew ; Hemi- 

 telia to Aspleniaceoi ; Trichopteris, Metaxya, and Alsoiihila, 

 to Polypodiacece. Most of them possess a cupshaped indu- 



distinct layers of cells. The walls of the contiguous cells are sometimes 

 perfectly confluent, as the cells of the leaves of many mosses and Jwn- 

 germannioe ; but, on the other hand, the line of demarcation is often 

 perfectly distinct. The notion, therefore, that the reticulations arise 

 from anastomosing veinlets is altogether wrong. See Presl, Hymeno- 

 phyllac6es, 1843. Aus den Abhandlungen der Kon. Bbhem, Gesells. 

 (v. Folge, Band 3.) 



* Disphenia is merely a Cyathea. 



f N"ow associated with them on account of its superior, not inferior, 

 indusium. 

 35 



