MANUAL 
OF THE 
NEW ZEALAND FLORA. 
Family 1. FILICES. 
PERENNIAL or very rarely annual plants, usually herbaceous but some- 
times arboreous (tree-ferns). Stems generally reduced to a rhizome, which 
may be short and tufted, or long and creeping or climbing ; or, in the case 
of tree-ferns, produced into an erect caudex or trunk. Leaves (fronds) either 
crowded at the end of the rhizome or distantly placed along it, continuous 
with the rhizome or jointed to it, sometimes simple and entire, but usually 
more or less deeply pinnately lobed or divided and frequently repeatedly 
so, more rarely dichotomously branched ; always circinate in vernation 
with the exception of the Ophioglossaceae. Spore-cases or sporangia usually 
arranged in groups (sor?) on the under-surface or margins of the fertile 
fronds, which are either similar to the sterile fronds, or narrower and more 
contracted, the divisions sometimes becoming linear and spike-like. Sori 
very various in size and shape and position, naked or covered when young 
by the recurved margin of the frond or by a special involucre (indusium). 
Sporangia many or rarely few in a sorus, often mixed with jointed 
hairs or scales, stalked or sessile, usually furnished with a complete or 
incomplete ring or annulus, dehiscing by a transverse or vertical slit, free 
or rarely coherent into a compound sporangium (synangium). Spores 
numerous, bilateral or tetrahedral. 
Ferns constitute one of the largest and most generally distributed of the families 
of plants, and are found in all quarters of the world, although most abundant in warm 
and moist climates. It is difficult to estimate the number of species, on account of the 
divergent views of authors, but probably from 5000 to-5500 would be a fair estimate. 
In the first edition of this book I followed the limitation of the genera proposed in Hooker 
and Baker’s “Synopsis Filicum,” that being the arrangement adopted in Hooker’s 
‘““ Handbook,’ Bentham’s “‘ Flora Australiensis,” and other colonial Floras; and the 
one then acquiesced in by most English systematists. But now pteridologists as a 
whole adopt a much larger number of genera, with a somewhat different sequence. And 
it must be admitted that Polypodium, Nephrodium, Asplenium, and other genera, as 
defined in the “Synopsis Filicum,” are for the most part artificial assemblages of 
species, possessing very diverse characters and relationships. But although it is com- 
paratively easy to separate a group here and there as being undoubtedly worthy of 
generic rank; it is admittedly a matter of great difficulty to prepare good and natural 
generic subdivisions for the whole family. The most satisfactory classification yet 
propounded is that given by Diels and others in Engler and Prantl’s ‘* Die Naturlichen 
Pflanzenfamilien,” where the class Filicales is divided into 12 families and 140 genera, 
against the 75 genera adopted in the “Synopsis Filicum.” After some consideration, 
{ have decided to follow this classification, as restated and slightly amended by 
Christensen in his ** Index Filicum ”’ (1906). 
i—FI. 
