ye d ee la 
1915] Fernald,— The American Ostrich Fern 163 
Deutschl. i. t. 24); and they are indicated by the phrase of Ledebour 
and of Koch: “pinnis linearibus integris." In the American plant 
the fertile pinnae are commonly pinnatifid or, as originally expressed 
by Michaux, “quasi noduloso-articulatis." This character, well 
shown in fairly mature specimens, is also indicated in the illustrations 
in Schkuhr's Kryptogamische Gewüchse, 1. t. 104. 
In all the European material examined the stipe (especially the base) 
of the fertile frond bears closely appressed firm lustrous blackish scales, 
and these scales are apparently found on the stipes of the sterile 
fronds as well. Such sterile fronds as the writer has seen have been 
cut above the base, but in his detailed account of the plant Mr. James 
Britten says: “The petiole is short, and is dilated at the base, where it 
joins the stem, and there covered with nearly black scales."? The 
writer has closely examined more than 100 numbers of the American 
plant, mostly showing the base of the stipe, and in no case has he been 
able to find any of the appressed black scales which characterize the 
base of the stipe in the European. He has also failed to find black 
scales on the fresh material. Instead the American plant has the 
base of the stipe covered with very thin membranous pale brown or 
cinnamon-colored scales. 
The sterile frond of the European plant is broadly oblong to nr 
lanceolate and comparatively thin in texture; that of the American 
plant more elongate and of firmer texture, the margins of the pin- 
nules often revolute. In the European the pinnae are nearly hori- 
zontal, in the American commonly more obliquely ascending; and the 
American plant is more erect and of greater stature than the European. 
Thus, Moore, describing the European plant, speaks of the sterile 
fronds as “ reclining at an angle of about 50°,” 3 and Britten speaks 
of them as “elegantly curved outwards,” 4 and Moore recognized his 
Struthiopteris germanica, var. pensylvanica because it “is more erect 
in habit.” As to stature, Britten says of the sterile fronds of the 
European plant, “sometimes attaining a length of as much as five feet, 
though usually about three feet" and “ the main pinnae are four or five 
inches long”; while Ascherson & Graebner, going into more detail, say 
that the frond is “up to 1.7 m. long" and that its stipe is “ up to 12 em. 
1 Ledeb. Fl. Ross. iv. 527 (1852-53); Koch, Fl. Germ. ed. 3, 739 (1857). 
? Britten, Eur. Ferns, 2 (1881). 
3 Moore, Ferns Brit. and Exot. ii. 138 (1862). 
1 Britten, Eur. Ferns, 2 (1881). 
