192 POLYSTICHUM ANGULARE. 



Pohjstichum angulare is a siiecics very easily cultivated, 

 growing luxuriantly in our ordinary ferneries in any light 

 loam, and especially delighting to grow in a soil that is 

 enriched by decaying vegetable matter. It prefers a well- 

 drained somewhat shady situation, and requires abundance of 

 space for the expansion of its roots. 



There are so many well-marked varieties, that a fine collection 

 of this single species will alone occupy a large space in the 

 British fernery. Indeed, not only are there more than one 

 hundred and fifty named varieties, but there are at least one 

 hundred forms of some of these varieties, combining the 

 characteristic features of one or more other forms in combi- 

 nation with its own particular form. Thus, the section Tri- 

 pinnatum embraces a vast number of plants very distinct in 

 character from each other, yet bearing primary features that 

 mark the particular variety from whence it takes its name. 

 The same may be said of the varieties Biserratum, Decompositum^ 

 Laxum, Laciniatum, Cristatum, Proliferum, Semitripinnatum, 

 Decurrens, and Dissi7nile. Were all the varieties to receive 

 name there would be no end to the number of varieties. 

 Some are more, and others less-developed forms, and each 

 variety will frequently change its character on becoming more 

 mature; thus, Semitripinnatum may become a fully-developed 

 Tripinnatum, or even become Suhquadripinnatum. It therefore 

 requires great care in distinguishing many of the forms, but at 

 the same time, when special characters are apparent, it seems 

 desirable to distinguish these, although they may in some 

 respects approach one or other of existing forms. In Tri- 

 pinnatum, for instance, the original plant, brought into notice 

 by myself, is quite distinct from the many forms which now 

 bear this name; and I agree with Mr. Wollaston that the 

 two forms cannot belong to the same variety; and although 

 this was the first which received the name, still the subsequent 

 ones are simply tripinnate varieties, and answer exactly to their 

 name, whereas the original form has several marked features 

 that do not of necessity belong to a tripinnate variety, (such 

 as the peculiar chaffy appearance of the under side of the 

 fronds and the horizontal position of the pinna;, these being 

 peculiar to this plant alone, and not being requisite features 



