270 THE BRITISH FERNS. 
Caudex short, decumbent, spreading, tufted, the crown sparingly 
furnished with a few very narrow pale brown scales. Fibres numer- 
ous, branched, wiry." 
Vernation circinate. 
Stipes slender, brittle, variable in length, sometimes quite short, 
sometimes one-third to one-half the length of the frond, pale-coloured 
except at the base which is brownish; terminal and adherent to the 
caudex. Secondary rachis narrowly margined. 
Fronds three to six or eight inches long, herbaceous, bright pale 
green, erect, smooth, lanceolate, bipinnate, or almost tripinnate in 
luxuriant fronds. Pinne ovate, acute, unequal. Pinnules bluntly 
or sometimes acutely ovate, with a narrow stalk-like attachment, 
deeply pinnatifid ; the lobes linear or linear-oblong, blunt, obscurely 
toothed, or sometimes with short distinct erect teeth which are blunt- 
pointed or retuse. In the larger pinnules the lobes, though still 
decurrent, and not truly separate, are distant and nearly divided to 
the rachis, so that the fronds are almost tripinnate. The fronds are 
occasionally forked. 
Venation of the pinnules consisting of a costa or midvein, from 
which an alternate lateral branch or vein is directed into each lobe, 
and there branches into several venules, which terminate in the 
retuse apices of the teeth; each tooth is thus apparently directed 
towards a sinus of the margin. 
Fructification scattered over the back of the frond. Sori numerous, 
sometimes crowded, small, round, medial on the veins, indusiate. 
Indusium a small delicate transparent membrane, which is ovate 
acute, slightly jagged in front, attached behind the sorus, projected 
forwards over it, becoming at length reflexed. Spore-cases roundish- 
obovate. Spores oblong, echinate. 
Duration. The caudex is perennial. The fronds are annual, 
appearing in May and perishing in autumn. 
The plant found at Leyton is generally admitted to be the Polypo- 
dium regium of Linneus, and it is certainly the P. alpinum of Wulfen. 
It seems therefore proper to adopt, as Presl has done, the older specific 
name ; but the specimen in the Linnean herbarium it must be 
observed, is not quite satisfactory evidence in support of this view. 

