Osmunda regalis var. spectabilis (Willdenow) A. Gray, Manual ed. 2. 600. 1856.
Osmunda spectabilis Willdenow, Sp. Pl. 5(1): 98. 1810
Leaves 2-pinnate; petioles ± length of blades, winged, with light brown hairs, glabrate at maturity. Sterile leaves broadly ovate, ca. 0.75--1 m; pinnae lanceolate, lacking tuft of hairs at base; pinnules short-stalked, base oblique to somewhat truncate, margins subentire to remotely dentate, apex acute to rounded. Fertile leaves with greatly reduced sporangia-bearing pinnae at apex. Sporangia greenish, turning red, then rusty brown. 2 n =44.
Sporulation early spring--midsummer; 0--2300 m; St. Pierre and Miquelon; N.B., Nfld., N.S., Ont., P.E.I., Que.; Ala., Ark., Conn., Del., Fla., Ga., Ill., Ind., Iowa, Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., N.H., N.J., N.Y., N.C., Ohio, Okla., Pa., R.I., S.C., Tenn., Tex., Vt., Va., W.Va., Wis.
The chloroplasts within the spores give the young sporangia their green color. As the spores mature and are shed, the sporangia change color to a distinctive rusty brown.
Osmunda regalis var. regalis is widely distributed in Europe and Asia and is widely cultivated as an ornamental.
Lvs mostly 5-18 dm; petiole glabrous; blade bipinnate, broadly ovate, to 5.5 dm wide; pinnae 5-7 pairs, subopposite, the lowest slightly reduced; pinnules alternate, 7-
10 to a side, oblong, to 7 נ2.3 cm, sessile or nearly so, rounded and oblique at the base, obtuse, serrulate, finely and closely veined; fertile pinnae borne at the ends of some of the blades, several pairs, the larger segments oblong, 6-11 נ2-3 mm, at first greenish, eventually brownish; 2n=44. Swamps and moist places, mostly in acid soil; circumboreal, in Amer. from Nf. to Sask., s. to Fla., Tex., and trop. Amer. Spring-early summer. The Amer. plant is var. spectabilis (Willd.) A. Gray.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.