670 FiLiCES. (ferns.) 



pinniE (each l"-lj" long). — Low grounds, pine barrens of New Jersey : very 

 local. Sept. 



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



Fronds twining or climbing, bearing stalked and variously lobed (or com- 

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

 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 Schizasa, but oblique, fi.xcd to the 

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

 sium. CName from XvywSrjs. Jlexlble.) 



1. L. palm^tum, Swartz. Very smooth; 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 palmately 4 - 7-lobed 

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

 terminal panicle. ( Hydrogldssum, Willcl. ) — Shaded or moist grassy places, 

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



20. OSMIJNDA, L. Flowering Fekn. (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-pedicelled 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 strite, 

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

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

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



* Fronds twice pinnate, JertUe at the top. 



1. O. reg&.lis, L. (Flowering Fern.) Very smooth, pale green (2°^ 

 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 raccmose-panicled at the 

 summit of the frond. (0. spectabilis, Willd. 0. glixnciscens, Link, Mettmius.) 

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

 Europe, but are sometimes found here. Maj', June. (Eu.) 



* * Sterile fronds once pinnate : pinna deeply pinnatijid; the lobes entire. 



2. O. Claytoni^na, L. Clothed with loose wool when unfolding, soon 

 perfectly smooth (2° -3*^ high); pinnce oblong-lanceolate, with oblong obtuse 

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

 sporangia greenish turning brown. (0. interrupta, Michx., ^-c.) — Low 

 grounds: common. May. — Fruiting as it unfolds. — This, being Clayton's 

 plant (as ascertained in 1839, both from the Claytonian andLinna;an herbaria), 

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

 specimens in which the fructification was thought to be terminal. 



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

 when young ; sterile fronds smooth when full gro'wn, the lanceolate pinnse pin- 



