38 



THE FLORIST. 



and more numerous as well as definite in form and arrangement. The 

 characteristics of this group are sometimes simulated by species referred 

 to the former, in which the definite reticulate sori happen to be crowded, 

 and when mature effused, so as to appear to form one mass ; but in 

 such cases the removal of the spore-cases will generally reveal the distinct 

 nature of the receptacles. The remaining group consists of Ferns in 

 which the spore-cases occupy the entire under surface (sometimes both 

 upper and under surface) of the frond, growing both from the veins and 

 the spaces intervening, in which cases the receptacles are said to be 

 universal. In this group it is usual for a portion of the fronds to be 

 spore-bearing, and these more or less contracted, while the remainder 

 are entirely destitute of spore-cases, and not contracted. In a few 

 kinds it is the upper parts of the frond instead of distinct fronds 

 which are spore bearing, while the lower parts are sterile. When 

 this distinct mode of growth occurs, namely, the one portion of 

 the fronds spore-bearing and contracted, and the other not so, the 

 fronds are said to be dimorphous, that is to say, of two forms, 

 and the one form is referred to as the sterile the other as the fertile 

 frond. This distinction in the mode of growth, which is more or less 

 marked throughout the whole of the group now under notice, occurs here 

 and there among the Ferns referred to the other divisions. 



The foregoing remarks will have indicated the three primary 

 divisions of this rather unwieldy group, and our further enquiries will 

 have been thus facilitated. 



Those Ferns, . then, which have the receptacles universal, form the 

 first division or section, the Acrostic hece. They are placed first in the 

 series, because, having the whole surface of their fertile fronds spore- 

 bearing, both veins and parenchyma being alike affected, they are 

 regarded as those in which the fertile principle is most thoroughly 

 developed. Those genera in which the receptacles form a compound mass 

 of crowded reticulations (so much crowded, indeed, that in the fertile 

 portions there is hardly any vacant space between the delicate veinlets 

 of which they are formed), and bearing large effused masses of spore- 

 cases, form a second distinct section, the Platycerice. These two groups 

 may be dismissed with a few further particulars. 



The Acrostichece comprise fourteen genera, whose connecting character 

 is, of course, the universal receptacles. They range conveniently in 



two divisions, the first having the 

 fronds, that is, the fertile ones, 

 wholly fructiferous ; and the 

 second having the upper pinnae 

 wholly fertile. The first division 

 includes Polybotrya, Rh ipidopteris, 

 Elaphoglossum, and Lomariopsis, 

 with free veins ; Stenochlcena and 

 Olfersia with combined veins ; 

 Soromanes, with connivent veins ; 

 21.ACROSHCHE*: Elaphoglossum conforme. and ^feurocallis, Hpnenodium, 



Stenosemia, Pcecilopteris, and Anapausia, with the veins reticulated. 

 The second division consists of Acrostic/ntm and Photinopteris, both 



