[Aphyllocalpa regalis (L.) Lag., moreOsmunda capensis C. Presl, Osmunda hilsenbergii Hook. & Grev., Osmunda obtusifolia Kaulf., Osmunda palmeri , Osmunda plumieri Tausch, Osmunda regalis f. abyssinica Kuhn, Osmunda regalis var. abyssinica (Kuhn) Pic. Serm., Osmunda regalis var. brevifolia Desv., Osmunda regalis var. capensis (C. Presl) Milde, Osmunda regalis var. plumieri (Tausch) Milde, Osmunda schelpei A.E. Bobrov, Osmunda transvaalensis A.E. Bobrov, Struthiopteris regalis (L.) Bernh.]
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. 2n = 44.
Sporulation early spring--midsummer.
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 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 [now treated as a distinct species: O. spectabilis].
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.