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[fili 



ceoe. of -which the two first, sometimes 

 called pseudo-Ferns, are very limited, while 

 the latter, containing the true Ferns, in- 

 cludes the greater portion of all the known 

 species. 



The three groups just named are distin- 

 guished from each other by the nature and 

 structure of their spore-cases. The pre- 

 sence of the annulus or ring around the 

 spore-case, in some form, either completely 

 surrounding it, or in a more or less rudi- 

 mentary condition, is the distinctive pecu- 

 liarity of the Polypodiacece ; while the Ma- 

 rattiacece and the Ophioglossacece are sepa- 

 rated from it by the absence of any such 

 ring, rudimentaiw or otherwise, and are 

 distinguished from each other by the ob- 

 vious characters that the Marattiacece have 

 their sori dorsiferous, that is, on the back 

 or under surface of their fronds, as is com- 

 monly the case among true Ferns, while 

 the Ophioglossacece have their sori margi- 

 nal, the spore-bearing or fertile fronds 

 being contracted. The Ophioglossacece are 

 few in number, and present little differ- 

 ence of structure ; the Marattiacece, how- 

 ever, form three small tribes, of which 

 the Marattinece have their sori ranged in 

 two lines facing each other, forming dis- 

 tinct oblong masses ; the Kaulfussinece 

 have distinct circular sori, the spore-cases 

 I of each sorus being concrete into a sin- 

 gle annular series, and furnished with 

 openings towards the centre ; and the 

 ■Danceinem have their sori connate over 

 thewholeunder surface, which then shows 

 long parallel lines of small round cavities. 

 The Polypodiacece offer so much variety 

 of structure that it becomes necessary to 

 subdivide them, and for this purpose the 

 peculiarities in the form of the spore- 

 eases, or in their number and position, or 

 in the structure and development of the 

 annulus or ring, are most relied on. This 

 gives t'ae following groups: — Polypodi- 

 nem, the most extensive of all, with spore- 

 ! cases almost equally convex, having a 

 vertical and nearly complete ring, and 

 bursting transversely at a part on the an- 

 terior side, called the stoma, where the 

 stria? of the ring become dilated into 

 elongate parallel cells. Cyatheinece, with 

 spore-cases sessile or nearly so, seated on 

 an elevated receptacle, oblique-laterally 

 compressed, the nearly complete ring be- 

 ing, in consequence, more or less ob- 

 liquely vertical, that is, vertical below, 

 curving laterally towards the top, burst- 

 ing transversely; they approach very near 

 the Polypodinece, through some species 

 of Alsophila, in which the characteristic 

 obliquity of the ring is little apparent. 

 Matoninece, a single species only, with 

 spore-cases sessile, bursting horizontally, 

 not vertically, the ring broad, sub-oblique, 

 and nearly complete, the sori dorsal and 

 I oligocarpous, covered by umbonato-hemi- 

 ; spherical indusia, which are peltate or 

 | affixed by a central stalk. Gleicheninece, 

 with the ring complete transverse, either 

 truly or obliquely horizontal, the spore- 

 cases globose-pyriform, forming oligocar- 

 pous sori, i.e. sori consisting of but few 



spore-cases (two or four to ten or twelve) 

 situated at the back of the frond, sessile 

 or nearly so, and bursting vertically; 

 fronds rigid and opaque, and usually di- 

 chotomously-branched. Trichomanineae, 

 with the ring resembling that of the Glei- 

 cheninece, but the spore-cases lenticular, 

 clustered on an often exserted recep- 

 tacle, which is a prolongation of the vein 

 beyond the ordinary margin of the frond, 

 so that the sori become extrorse margi- 

 nal or projected outwards, as well as open- 

 ing outwardly ; fronds pellucid-membra- 

 naceous. Schizmnece, with the ring hori- 

 zontal or transverse, situated quite at the 

 apex of the oval spore-case, which is, in 

 consequence, said to be radiate-striate at 

 the apex ; the spore-case also sometimes 

 resupinate, or turned upside down, so that 

 the true apex is below ; habit sometimes 

 scandent. Ceratopteridinece, one or two 

 aquatic species, the spore-cases sometimes 

 furnished with a very rudimentary ring, 

 reduced, as in Osmundinece, to a few 

 parallel stria?, sometimes furnished with 

 a very broad and more lengthened ring ; 

 spores bluntly triangular, marked with 

 three series of concentric lines. Osmun- 

 dinece, with the spore-cases two-valved, 

 bursting vertically at the apex, the ring 

 very rudimentary, reduced to a few parallel 

 vertical stria? on one side near the apex 

 of the spore-case. In all but the last of 

 these groups, the spore-cases are not val- 

 vate, and consequently, when they open 

 for the liberation of the spores, they burst 

 partially or irregularly, and do not split at 

 the top in two equal divisions, as occurs 

 in the Osmundinece. 



These primary and secondary groups 

 will be more readily comparable in the 

 following summary : — 



Spore-cases ringless. 



1. Ophioglossace^s— Fructifications mar- 



ginal on rachiform fronds. 



2. aIarattiace^— -Fructifications dorsal 



on flat leafy fronds. 



§ Marattinece— Sori oblong, distinct, lon- 

 gitudinally biserial. 



§ Kaulfussinece— Sori circular, distinct; 

 spore-cases annularly concrete. 



§ Danosinem— Sori connate throughout. 



Spore-cases having a jointed ring. 



3. Poltpodiace^: — Spore-cases not val- 



vate : rarely somewhat two-valved ver- 

 tically. 



§ Polypodinece — Ring vertical, nearly 

 complete ; spore-cases usually stalked, 

 gibbous ; receptacles superficial or im- 

 mersed. 



§ Cyatheineoe — Ring obliquely vertical, 

 nearly complete, narrow; spore-cases 

 crowded, sessile or subsessile, oblique- 

 laterally compressed; receptacles ele- 

 vated. 



§ Matoninece— Ring sub-oblique, nearly 

 complete, broad ; spore-cases few, ses- 

 sile, gibbous ; sori oligocarpous. 



§ Gleicheninece— Ring zonal, horizontally 

 or obliquely transverse, complete ; 

 spore-cases sessile or subsessile, ver- 



