670 FiLicES. (ferns.) 



pinnoE (each 1"-1^" long). — Low grounds, pine barrens of New Jersey: Tcry 

 local. Sept. 



19. LYGODIUM, Swartz. Climbing Fern. (PI. 19.) 



Fronds twining or cliinliing, bearing stalked und variously lobcd (or com- 

 pound) divisions in pairs, with mostly free veins; the fructification on sci)aratc 

 contracted divisions or spike-like lobes, one side of which is covered with a 

 double row of imbricated hooded scale-like indusia, fixed by a broad base to 

 short oblique veinlets. Sporangia much as in Schizaea, but oblique, fixed to the 

 veinlet by the inner side next the base, one or rarely two covered by each indu- 

 sium. (Name from Xvyabrjs. Jlixible.) 



1. L. palmatum, Swartz. Very smootli ; stalks slender, flexile and twin- 

 ing (l°-3° long), from slender running rootstocks ; the short alternate branches 

 or petioles 2-forked ; each fork bearing a round-heart-shaped i)almately 4 - 7-lobed 

 frondlet ; fertile frondlcts above, contracted and several times forked, forming a 

 terminal panicle. (Hydroglossum, Willd.) — Shaded or moist grassy places, 

 Massachusetts to "Virginia, Kentucky, and sparingly southward : rare. Sept. 



20. OSMUNDA, L. Flowering Fern. (PI. 19.) 



Fertile fronds or fertile portions of the frond very much contracted, and bear- 

 ing on the margins of the narrow rhachis-like divisions short-pedicclled and 

 naked sporangia : these are globular, thin and reticulated. Large, opening by a 

 longitudinal cleft into two valves, and bearing near the apex a few parallel strije, 

 the rudiment of a transverse ring. — Fronds tall and upright, from thickened 

 rootstocks, once or twice pinnate ; veins forking and free. Spores green. ( Os- 

 mundir, a Saxon name of the Celtic divinity, Thor.) 



* Fronds twice jnnnate, fertile al the top. 



1. O. regklis, L. (Flowering Fern.) Very smooth, pale green (2° v. 

 5° high); sterile pinnules 13-25, varying from oblong-oval to lance-oblong, 

 finely serrulate, especially towards the apex, otherwise entire, or crenately lobed 

 towards the rounded, oblique and truncate, or even cordate and semi-auriculate 

 base, sessile or short-stalked (l'-2' long) ; the fertile racemose-panicled at the 

 summit of the frond. (0. spectabilis, Willd. O. glauce'scens, Link, i\rettcnius.) 

 — Swamps and wet woods : common. The cordate pinnules arc commoner in 

 Europe, but are sometimes foinid here. May, June. (Eu.) 



* * Sterile fronds once pinnate : pinnve deeplij pinnutijid ; the lobes entire. 



2. O. Claytoniana, L. Clothed with loose wool when unfolding, soon 

 perfectly smootli (2° -3° high); pinme ohlomj-lanaolale, with oblong obtuse 

 divisions; some (2 -.5 pairs) of the middle pinnce fertile, these entirely pinnate ; 

 sporangia greenish turning brown. (0. intcrriipta, Michr., i^-c.) — Low 

 grounds: common. M:iy. — Fruiting as it unfolds. — This, being Cl.ayton's 

 plant (as ascertained in 1839, both from the Claytonian andLinnasan herbaria), 

 must bear the original Linnrean name, though wrongly described from young 

 specimens in wliicli the fructification was thought to be terminal. 



3. O. cinnain6raea, L. (Cinnamon-Fern.) Clothed with rusty wool 

 •when young ; sterile fronds smooth when full grown, the lanceolate pinnte pin- 



