CONCERNING NOMENCLATURE. 



N the scheme of the vegetable kingdom, 

 ferns are accorded a place below the 

 flowering plants. With the Fern-Allies 

 the club-mosses, quillworts and scour- 

 ing rushes they form the highest group 

 of the so-called flowerless plants. On 

 the one hand they are related to such 

 simple flowering plants as the pines, 

 palms, sedges and grasses, and on the 

 other to the mosses and liverworts. 



Among themselves they differ widely, and several 

 natural groups may be recognised. Formerly these 

 groups were all included in the single order Filices ; but 

 the modern and more scientific view makes them separate 

 orders. One of the chief points of difference between 

 them is found in the formation of the sporangia. In all 

 but the most primitive, there is a ring of stronger cells 

 extending around each sporange, which in most species 

 bursts at maturity, scattering the spores. The position 

 of this ring is of much importance in placing the genera 

 in the proper orders. There are five of these orders 

 represented in our fern-flora, four of which are relatively 

 insignificant. Their principal characteristics and the 

 tribes and genera they contain may be arranged in a 

 series, from simple to complex, as follows. The relative 

 size of the spore-cases are shown in the illustrations. 



