358 BROADHURST: STRUTHIOPTERIS IN NORTH AMERICA 
Most of the petioled species are very large, and complete 
sterile and fertile leaves are not always found in the same herba- 
rium number; therefore, in this paper the comparative height is 
often omitted, though it may be more or less accurately deduced 
from the figures given for the length of the sterile and the fertile 
fronds, respectively. 
Key to the petioled species 
B. STERILE PINNAE (AT LEAST THE LOWER ONES) PETIOLED;* RHIZOME SCALES RIGID 
OR FLACCID; PINNAE MORE OR LESS SCALY; INDUSIUM IRREGULARLY 
LACERATE TO FIMBRIATE WITH AGE 
Rhizome scales very slender, rigidly erect, with dark centers; 
vestigial pinnaet present; margins entire; coriaceous 
(rigid-herbaceous in S. Underwoodiana). 
Sterile lamina very abruptly reduced at the base (type A, 
with vestigial pinnae); pinnae crowded to overlapping, 
elliptical, obtuse; dried pinnae rolled and rufous below; 
margins revolute. 16. S. rufa. 
Sterile lamina abruptly reduced at the base (type D, 
with vestigial pinnae except in S. Shaferi); er 
nae never + haga or ee: secant A 
long to linea 
rolled, gray-green to yellowish ‘brown: or brown 
below; marginst not revolute. 
Apex of the sterile lamina gradually reduced; 
upper sterile pinnae not conspicuously dilated 
both ways at the base, the base of the lower ones 
cuneate, petioled; deciduously araneous below; 
vein s 8-20 to 1 cm.; rachis scales mixed 
with white, fibrillose ones. 25. S. Werckleané. 
Apex of the sterile lamina not reduced; upper sterile 
pinnae conspicuously dilated both ways at 
their base, the bases of the lower ones barely 
petioled, rounded; not araneous below; vein 
spaces 10-16 to I cm.; rachis without white, 
fibrillose scales 
Lower sterile pinnae prominently dilated or 
auricled at the base; stipe mE , 
long, without vestigial pinnae; costae not 
attened on the under side; vei es 15 OF 
lacerate to its base, concavely hollowed on Pe 
the sides of the lacerations 19. S. Shafer’ 
ed, have 
wa. iana and S. Shaferi, the only forms not distinctly petiol 
division 
rigid rhizome scales which are never found in the species in the “preceding 
see d 
t Except in S. Shaferi. ty glandulats 
t+ Incompletely and very narrowly so in S. Shaferi, which is peculiarly 8 
escription. 
