Family 1. OSMUNDACEAE 
By RALPH CURTISS BENEDICT 
Rhizomes erect or creeping, woody, the roots fibrous, not fleshy. Leaves 
fasciculate, inarticulate, pinnately divided, alike, or entirely dimorphic, or 
with dimorphic pinnae. Sporangia borne along the ultimate veinlets, either on 
the backs of ordinary leaves, or entirely replacing the vegetative tissue and in 
dense paniculate clusters, globose, short-pedicellate, longitudinally dehiscent, 
the annulus few-celled or wanting. Spores green,ephemeral. Prothallia green, 
flat, expanded, with a thickened ventral ridge on which the archegonia and 
antheridia are borne. 
1. OSMUNDA L,. Sp. Pl. 1063. 1753. 
Aphyllocaipa Cav. Anal. Ci. Nat.5: 164. 1802. 
Plenasium Presi, Tent. Pterid. 109. 1836. 
Osmundastrum Presl, Abh. Bohm. Ges. Wiss. V. 5: 326. 1847. 
Coarse plants with creeping, mostly subterranean rhizomes surrounded by a dense 
thick mass of fibrous hard black or dark-brown roots. Leaves densely clothed with long 
white or brown hairs when young, glabrous or nearly so when mature, dimorphic or with 
dimorphic pinnae, arranged in two circles, the sporophyls taller and erect, and in the cen- 
ter, but developed earlier and below the spreading sterile leaves, the stipes expanded just 
above the base to form sheathing wings. Sporangia replacing the leaf-tissue, and borne in 
dense paniculate clusters on the ultimate veinlets. 
Type species, Osmunda regalis L. 
Leaves normally entirely dimorphic, the sporophyls much contracted, the sterile leaves 2-pin- 
natifid, the pinnae with a tuft of tomentum at the base. 1. O. cinnamomea. 
Leaves merely partly dimorphic. 
Sporophyl with the apical portion fertile; sterile leaves 2-pinnate. 2. O. regalis. 
Sporophyl with median portion fertile; sterile leaves 2-pinnatifid, the 
pinnae without tomentum at the base. . 3. O. Claytoniana. 
1. Osmunda cinnamomea L,. Sp. Pl. 1066. 1753. 
? Osmunda bipinnata I,. Sp. Pl. 1065. 1753. 
Osmunda alata Goldie, Edinb. Phil. Jour. 6: 322. 1822. 
Osmundastrum cinnamomeum Pres], Abh. B6hm. Ges. Wiss. V.5: 326. 1847. 
Rhizomes and root-masses subterranean or partly aérial, and forming tussocks in wet 
ground, the roots black; leaves 50-150 cm. long, wholly dimorphic, the stipes 15-50 cm. 
long, the sheathing bases produced anteriorly to form two rounded stipuliform lobes, the 
stipe and rachis glabrous when mature but with tufts of tomentum at the base of each 
pinna; sterile lamina narrowly oblong or elliptic-lanceolate, 35-100 cm. long, 15-30 cm. 
broad, usually gradually narrowed above, acute, pinnate, the pinnae deeply pinnatifid, 
mostly in pairs, at least below, but not quite opposite, narrowly oblong, 8-18 cm. long, 
1.5-4 cm. broad, long-acute or acuminate, mostly oblique, but sometimes straight or some- 
what recurved, or with the tips curved up, glabrous or sometimes minutely viscid-glandular, 
rather shining below, the segments close, falcate, with the anterior margins concave, 
oblong, usually acute or acutish, but sometimes blunt or rounded ; veinlets once-forked ; 
fertile lamina very narrow, thick, erect, soon disappearing, the pinnae pinnate owing to the 
reduction of the leaf-tissue, the segments consisting merely of the midveins and shortened 
thickened veinlets, densely covered when mature with the cinnamon-brown sporangia. 
TYPE LocaLity: Maryland. : ; 
DISTRIBUTION: Eastern North America, Mexico, and the West Indies; also in southeastern Asia. 
ILLUSTRATIONS: D. C. Eaton, Ferns N. Am. fl. 29, 7. 3-5 ; Lowe, Ferns Brit. & Exot. 8: £1. 2; 
Britt. & Brown, Ill. Fl. f 9. 
VoLUME 16, Parr 1, 1909] 27 
