456 ACOTYLEDONOUS PLANTS. 



2-valved involucre of the same texture as the frond ; valves 

 plane, outer one free. 



H. ciliatum Smith : frond pinnate ; lower divisions larger ; upper 

 ones gradually smaller, pinnatifid ; segments linear-obtuse, bifid, cili- 

 ate, hairy on the veins j stipe and rachis winged and ciliate. Tricho- 

 manes ciliatum Stcartz* 



HAB. Trunks of trees in shady places. Perm, and Vir. U. 

 Pursh. 



12. STRUTHIOPTERIS. WiUd. 



Capsules densely covering the back of the frond. Involu- 

 cre scaly, marginal, opening internally. x 



8. germanica WiUd. : sterile fronds pinnate ; pinnae pinnatifid, ses- 

 sile ; segments entire, rather acute ; the lower ones somewhat elon- 

 gated and S. pennsylrxinica WiUd. Onoclca struthiopteris Sicartz. 

 O. nodulosa Schk. Mich. 



HAB. Low grounds. Can. and N. S. July. It. One of our 

 largest ferns, the sterile fronds being often 3 feet high and ar- 

 ranged in a circular form, with a few much smaller fertile ones 

 in the centre. I think there can be no doubt of the identity o 

 our plant with the foreign S. germanica. 



13. DICKSONIA. L'Hcrit. 



Sori punctiform, marginal, roundish and distinct. Involu- 

 cre double ; outer one superficial, opening outwards ; the 

 other marginal and opening inwards. 



D. pilosiuscula WiUd. : frond bipinnate ; pinnules decurrent, ob- 

 long-ovate, pinnatifid segments incisely dentate ; sori solitary, minute ; 

 stipe and rachis hairy. D. pnbcscens Schk. Nephrodium punctilobum 

 Mich. Aspidium punctilobum WiUd. Pursh. Torr. 



HAB. Shady places. Can. td Vir. ; common. . July. If. 

 Fern 2 3 feet high, growing in tufts, of a delicate habit. Stipe 

 nearly smooth below, but becoming hairy as it passes into the 

 rachis. Frond large and long, lanceolate, somewhat acuminate, 

 yellowish-green. Sori solitary, minute, .near the divisions of 

 the segments. A true Dicksonia* 



Div. II. OSMUNDAE^E. Capsules destitute of a ring, re- 

 ticulated, striated with rays at the apex, opening lengthwise 

 and usually externally. 



14. OSMUNDA. Linn. 



Capsules subglobose, pedicelled, radiate-striate, or wrink- 

 led, 2-valved, with a hinge at the joining of the valves, either 

 occupying the "lower surface of the contracted frond, or disposed 

 in the shape of a raceme or panicle. Involucre none. 



