FERN FAMILY. 9 
1. Onoclea sensibilis L. Sensitive Fern. 
(Fig. 14.) 
Onoclea sensibilis I. Sp. Pl. 1062. 1753. 
Rootstock rather slender, copiously rooting ; fer- 
tile leaves 1°-2's° high,. persistent over winter, 
much contracted, and with short pinnules rolled 
up into berry-like closed involucres forming a nar- 
row panicle; sterile leaves 1°-4'2° high, broadly 
triangular, deeply pinnatifid, the segments lanceo- 
late-oblong, entire, undulate, or the lower pairs 
sinuate-pinnatifid ; veins freely anastomosing ; low- 
est segments tapering both ways from the middle; 
veins forming a somewhat regular series of semi- 
elliptic areoles next the midvein and numerous 
smaller areoles between this series and the margin. 
In moist soil, Newfoundland and Ontario to the 
Northwest Territory, south to Florida, Louisiana and 
Kansas. Ascends to 3000 ft. in Virginia. Various in- 
termediate forms between the sterile and fertile leaves 
occur. Sensitive to early frosts. Aug.—Nov. 
2. Onoclea Struthiopteris (L,. ) Hoffm. 
Ostrich Fern. (Fig. 15.) 
Osmunda Struthiopleris l,. Sp. Pl. 1066. 1753. 
Onoclea Struthiopteris Hoffm. Deutsch. Fl. 2: 11. 
1795- 
Rootstock stout, ascending, bearing a circle 
of sterile leaves with one or more fertile ones 
within. Fertile leaves 1°-114° high, simply 
pinnate with necklace-shaped pinnae which are 
formed of the closely revolute margins; sori 
crowded and confluent; sterile leaves 2°-7° 
high, 6/-15’ wide, broadly lanceolate, pin- 
nate, much the broadest above the middle and 
gradually tapering below, the lower pinnae 
being gradually much reduced; veins pin- 
nate, free and simple ; texture firm ; rootstocks 
stoloniferous. 
In moist thickets, especially along streams, Nova 
Scotia to New Jersey, west to British Columbia and 
Illinois. Ascends to 2000 ft. in Vermont. Also in 
Europe and Asia. July—Oct. 
2. WOODSIA R. Br. Trans. Linn. Soc. 11: sigh, © anche 
Small or medium-sized ferns, growing in rocky places, with 1-2-pinnate or pinnatifid 
leaves and round sori borne on the backs of simply forked free veins. Indusia inferior, 
thin and often evanescent, roundish or stellate, either small and open or early bursting at 
the top into irregular lobes or segments. Stipes often jointed above the base and separating 
at the joint. [Name in honor of Joseph Woods, 1776-1864, English architect and botanist. ] 
About 15 species, natives of temperate and cold regions. Besides the following, another oc- 
curs in the southwestern United States. 
Indusium minute or evanescent, flat, concealed beneath the sorus, its margin cleft into slender 
hair-like segments. 
Stipes obscurely jointed near the base; cilia of the indusium inflexed over the sporanges. 
Leaves with more or less rusty chaff underneath. 1. W. Ilvensts. 
Leaves glabrous or nearly so. 
Leaf lanceolate, not tapering below; pinnae cordate-ovate, 5-7-lobed. 2. W”. alpina. 
Leaf linear or linear- oblong, often tapering both ways; pinnae deltoid. 3. W. glabella. 
Stipes not jointed; cilia of the indusium very short, hidden by the sporanges. 
Puberulent; indusium deeply cleft, ending in hairs with cylindric cells. 4. W. scopulina, 
Leaves and stipes glabrous ; indusium divided to centre into beaded hairs. 5. HW”. Oregana, 
Indusium distinct, at first enclosing the sporanges, splitting into jagged lobes. 6. W. obtusa. 
