634 CLX1V. FILICES. OSMUNDA, 



united ; fertile fronds bipinnate, with recurved and globular contracted seg- 

 ments. Common in low grounds. Fronds about a foot high, the barren ones 

 broad and somewhat triangular in outline, composed of broad, oblong, sinuate 

 divisions, the upper ones smaller, nearly entire, becoming united at base. The 

 fertile frond is very dissimilar in its form to the others, resembling a compound 

 spike, enclosing the fruit in the globular segments of its short divisions. Color 

 dark brown. July. 

 P. obtusilobata. Torr. (O. obtusilobata. Schk.) Lfls. opposite; segm. rounded. 



12. STRUTHIOPTERIS. Willd. 



Gr. orpovSos, the ostrich, irrepov, wing, or plume ; from the resemblance. 



ThecaB densely covering the back of the frond ; indusia scaly, 

 marginal, opening internally. 



S. GERMANICA. Willd. (S. Pennsylvania. Willd.) Ostrich Fern. 



Sterile fronds pinnate; leaflets pinnatifid, sessile; segments entire, rather 

 acute, the lower, ones somewhat elongated. A fern of noble size and appear- 

 ance, growing in low woods and swamps. The sterile fronds are often 5 or 6f 

 high, commonly about 3, numerous, in circular clumps. Stipes smooth, chan- 

 neled ; leaflets pinnatifid, with numerous segments, the lower of which are the 

 more narrow and acute, all more or less connected at base. Fertile fronds few, 

 in the midst of the sterile, much smaller, the leaflets with numerous, brown- 

 ish, contracted segments, densely covered by the fruit beneath. Aug. 



TRIBE 2. OSMUXDIACEJE. Thecsc destitute of a ring, reticulated, stri- 

 ated with rays at the apex, opening lengthwise and usually externally. 



13. OSMUNDA ? 



ThecaB subglobose. pedicellate, radiate-striate, half-2-valved, collect- 

 ed on the lower surface of the frond or a portion of it, which is more 

 or less contracted into the form of a panicle. 



* Fertile fronds distinct from the sterile. 



1. O. CINNAMOMEA. Cinnamon-colored Fern. 



Sterile frond pinnate, leaflets elongated, pinnatifid, segments ovate-oblong, 

 obtuse, very entire; fertile frond bipinnate, leaflets contracted, paniculate, sub- 

 opposite, lanuginous ; stipe lanuginous. This is among the largest of our 

 ferns, growing in swamps and low grounds. Fronds numerous, growing in 

 clumps, 3 5f high, most of them barren, the stipe and rachis invested with a 

 loose, cinnamon-colored wool. The fertile fronds resemble spikes, 1 2f long, 

 an inch wide. Leaflets all fertile, erect, with the segments covered with fruit 

 in the form of small, roundish capsules, appearing, under a microscope, half- 

 2-cleft. June. 



* * Portions of each frond fertile. 



2. O. REGALIS. Michx. (O. spectabilis. Willd.') Royal Flowering- Fern. 



Fronds bipinnate, fructiferous at the summit ; segments of the leaflets lance- 

 oblong, distinct, serrulate, subsessile ; raceme large, terminal, decompound. A 

 large and beautiful fern, in swamps and meadows. The fronds are 3 4f high, 

 smooth in all their parts. Leaflets or pinnae opposite, remote, each with 69 

 pairs of leaves with an odd on?. These are an inch or more long, \ as wide, 

 obtuse, the petioles %" long. Above, the frond is crowned with an ample 

 bipinnate raceme of a deep fulvous hue, with innumerable, small, globular, 

 2-valved thecae entirely covering the segments. June. 



3. O. CL-AYTONIANA. * 



Frond pinnate ; leaflets or pinna pinnatifid, the upper ones contracted and 

 fertile. Smaller than either of the foregoing, found in swamps, Cambridge, 

 N. Y., Dr. Beck, W. to Wise., Dr. Lapham ! Fronds 1 2f high. Pinnae ob- 

 long, obtuse, 2 4' long, tomentose in the axils. Segments entire. Each frond 

 b^ars a terminal, bipinnate, rust-colored, erect panicle, covered with fruit. May. 



4. O. INTERRUPTA. Michx. 



Frond pinnate, smooth ; leaflets nearly opposite, pinnatifid ; segments ob- 



