Genus IV: POLYSTICHUM (Roth), Schott. 
Gen. CHAR.—Sori indusiate, globose; the receptacles medial or 
rarely terminal on the venules. Indusium orbicular, peltate. Veins 
pinnato-furcate or simply forked, from a central costa ; venules free, 
the lower anterior one usually, sometimes more, fertile. 
Fronds simple pinnate or bi-tri-pinnate, rigid, coriaceous, the 
margins usually mucronato-serrate. 
Caudex short, thick, erect. 
This extensive genus is very well marked by technical characters 
derived from the fructification. The original Polystichum of Roth, 
Aspidium of Swartz, and Tectaria of Cavanilles, all proposed about 
the same date, were intended to separate the indusiate group at 
that time referred to Polypodium, from among the typical non- 
indusiate species. In the disposition of the two former of these 
names, long since made by Schott and adopted by Presl, by which 
Aspidium Lonchitis was made the type of Polystichum, and Aspidium 
trifoliatum of Aspidium, we entirely concur; though it may be 
regretted that either the expressive name proposed by Cavanilles, 
or the still older Dryopteris of Adanson, was not used by Presl, 
instead of the more modern inexpressive name, Lastrea of Bory, for 
the group of which the old Aspidium Filix-mas, and Aspidium dilata- 
tum are the types. This latter name, Lastrea, having been, however, 
employed so long ago, both in the arrangements of Presl and 
J. Smith, on which modern views of classifioation are mainly 
based; and the group being so extensive, that the substitution of 
another generie name would involve multitudinous changes, it is 
doubtless: better now to acquiesce in the nomenclature of Presl, 
so far as regards the application of the name of Lastrea to the 
free-veined reniform Aspidiee, and that of Nephrodium to those 
having anastomosing veins, than to adopt any other, or attempt a 
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