CHAPTER VIII. 



PL AT Y CERIUM, Desvaux. 



(Plat-yc-er'-i-um.) 



Elk's -horn and Stag's -horn Ferns. 



HE name Flaty cerium is derived from platys, broad, and keras, 

 a horn, on account of the fertile fronds of these plants being 

 divided into broad segments like stags' horns. They are, with 

 the Acrostichnms, the only Ferns comprised in the tribe 

 Acrosticheos, and form, in Hooker and Baker's " Synopsis 

 Filicum," Genus 61, thus occupying an intermediate position between the 

 Acrostichums and the Osmundas. Platy cerium is a small group of plants 

 (about half-a-dozen species) of widely -separated habitats, some being found in 

 Temperate Australia, others in the Philippine and Malayan Islands, and one 

 at least in Africa. The genus is well marked, and is rendered very distinct 

 through the repeatedly -forked character of the fertile fronds of most of the 

 species. Besides the unique mode of growth of these Ferns, their distinguishing 

 character resides in the disposition of the sori (spore masses), which form 

 large patches on the lower surface of the fertile fronds, and are in most cases 

 situated at their extremity, which they cover to the length of sometimes quite 

 eight inches : there are, however, one or two exceptional instances in which 

 the sori occupy only the disk or broader portion. The fertile fronds are in 

 all cases, as regards shape, size, and texture, thoroughly different from the 

 barren ones, which are of a peculiar rounded shape, convex, and of a more 

 or less thick, parchment-like texture. There are no British representatives 

 of the genus. 



