THE COMMON MSAKKS. 



P. Wpflwfrlfcf TlmnWiy. h not diMTn^uUhaMr from P. ooatfiV* by it* Approximate tegmenta And the &ctdw bin? of 

 the nehidei on *hkh A;ardh dcpundi, for »x> find both lb«e peculiarities in BrituS »iwimfm gathered by 

 OVHttra ftt irnmnttfad, aod in other* from WickW, ttunmunwAtod by Mr- It, Itirrinston. Tbo vadium of the 

 •urtVe and of the raehiv— the hllcr nlmott the only dirteienoo it pw»ent*«-b loo tarubk- And unimportant a feature 

 to bo ninth depended on ; bewdee tin*, fa*oj*Wa iUelf iometime* h*j Ibo AegnieiiU dirtiuet, wbJeh U aiiJ lo bo the 

 dbUPfukUBg nuvrk ot*$vili**. Ilenee w* are untbte to aenaratc P. Amnjiiiom even n> a variety, though iU forma 

 Are. *ti think, analogou* to thoio undivided Uritbti wb'fonni called inttytrrim*. In like manner, the J\ rtearrdfa 

 uf Walttch, under vhieh b mrluded tho P /«m and P. IffyA/wiM of Wallich, an 1 the P. rjctt+a of Illume, oflVr* no 

 dutii>£uubia£ ehiroctcn, but ajpun aecordi with the ■ub+vtrivty i*t<$trri*a; untie tho J*. Attaporifa of GaudirWtd 

 at*»ear* to fc* aim a form of avvitina with wnaller |*irt*, pcrliani dUtiuguuhabto a* a variety, Hkc P. caiuftr/ti of the 

 Ufatt Indie* and the Southern United States, with long narrw-tailed dtiitiona, ift n fairly marled variety; Mitioii, 

 ure think, tho broad* ntiunited North nod Xorth*We»t American form, found alto in Madeira (tbo i 1 * UtiwuU of 

 ■Want), figured by Sehkuhr under tbe nam* of P. tam4*t*» The P r*mlr*f* of AmlraLuia preacuU an appreciable 

 dirTcrcuee in its interjected lobe, and ought protobly lo be kept ditfinet, including at varietiea the P< awAaeniW of 

 ftrtuil, and oUhy part* of South America, and tho P. mtUoffdfo, Jr/ua t and t^riytra^ of Wallicl^ rtnlhea of India. 



Rhizome as thick as one's little linger, subterraneous, creeping, black and somewhat velvety 

 externally, white succulent ami starchy within. Fibres branched, downy. 



Stipes lateral and distant on the rhizome and adherent to it; spindle- shaped, black ami velvety 

 at the base, i. c. beneath tho surface ; above yellowish green, pubescent when young, afterwards smooth, 

 but sharply angular when mature, and about or rather over half tho length of the frond ; a transverse 

 section shows the cuds of the vascular bundles arranged so as to present a fanciful resemblance to the 

 imperial eagle, whenco the specific name. Jtachis channelled above, rounded behind, sometimes 

 slightly asperulous. 



Vernation circinatc ; the rachis is in an early stage bent down abruptly close against tho stipes. 



Fronds variable in size, outline and composition, deep green. In poor soils they vary from six to 

 eighteen inches in height, and in more favourable localities they reach from three or four to eight or ten 

 feet or more in height ; in the former cases the outline is nearly triangular, and from the lower pair of 

 branches only being well developed, they appear three-branched ; in the latter eases they arc more 

 elongated or oblong, and the growth consists of a series of branches in pairs, successively developed. 

 In composition the smaller arc bipinnate, the larger fronds tripinnatc. Pinna* or branches ovate or 

 oblong-ovate, opposite, often distant Pinnules or secondary pinnw narrow lanceolate or narrowing 

 from a broad base, opposite or alternate, contiguous, bluntish or sometimes caudate. Pinnulcte sessile, 

 entire or sinuate, oblong and adnatc by their whole breadth, or more ovate pinnatilid, and then 

 with a narrower attachment, blunt at tho apex, smooth above, hairy beneath ; tho pinuatitid ones 

 with blunt linear oblong or shorter triangular lobes. 



Venation of the more entire pinnulcta, consisting of forked veins arcuatcly spreading from a stoutish 

 midvein ; these veins are one, two, or three times forked, the venules extending to the margin. In tho 

 pinnatiful pinnulcta the veins become secondary midveins to the lobes, and give oft* a scries of once or 

 twice forked veins; in these latter the lowest branches right and left of the secondary midveins 

 frequently meet and unite forming a series of costal arcolcs. Along the edges of the fertile pinuulets 

 extends a longitudinal subinarginal vein, which becomes the receptacle. 



Fructification abundant on the back of the fronds, sub-marginal. Sari linear, continuous, the reccp- 

 tacular vein occupying nearly the margin of the pinnulets, and lying as it were in the axil of the 

 indusium. Jndusium linear, continuous, consisting of a thin whitish fringed membrane growing from the 

 outer edge of the receptacle, and folded inwards over the sporc-cascs ; beneath the spore-eases and 

 growing from the inner edge of the receptacle is another similar fringed membrane ; the fringes consist 

 of small jointed hairs. Spore-cases roundish obovate. Spores round oblong or angular, muriculato. 



Duration. The rhizome is perennial* The fronds arc annual, growing up early in May, but very 

 impatient of cold or frosts, and killed by the early frosts of autumn. 



A common and well-known Fern, but also cosily recognised technically among British Perns, by tho 

 continuous lines of marginal sori, on comjKmnd fronds, not contracted. Like all other widely diffused 



