370 FERN FAMILY. 



17. STRTJTHIOPTERIS, OSTRICH-FERN (which the name means 

 in Greek, from the large plume-like sterile fronds). 



S. Germanica. Alluvial grounds, N. : sterile fronds tall, 2 -5 high, 

 lanceolate, narrowed at the base into a short angular stalk, pinnate ; pinnae 

 very many, narrowly lanceolate, pinnatifid more than half-way to the midrib ; 

 lobes numerous, oblong ; fertile fronds very much shorter, blackish, standing 

 erect after the others have withered. 



18/ONOCLEA. SENSITIVE-FERN. (Name, from the Greek, mean- 

 ing a closed vessel, referring to the berry-like fructification.) The only species is 

 O. sensibilis. Common in wet places : sterile fronds of all sizes up to 2 

 high, broadly triangular-ovate, the rhachis winged ; pinnae not many, lanceolate, 

 entire or obtusely lobed less than half-way to the midrib', veins everywhere 

 reticulated ; fertile fronds with few closely appressed pinnae. 



19. WOODSIA. (For Joseph Woods, an English botanist.) 



W. Obtusa. Rocky places, from Carolina N. : fronds 6' - 18' high, slightly 

 glandular, broadly lanceolate, pinnate with ovate or oblong deeply pinnatifid 

 or again pinnate divisions ; lobes oblong, obtuse ; indusium at first closed, 

 opening into a few ragged lobes. 



W. Ilvensis. Exposed rocks, common N., and along the Alleghnnics: 

 forms large tufts; fronds 4' -8' high, rusty chaffy beneath, oblong-lanceolate, 

 pinnate; divisions ovate, obtusely lobed; indusium obscure, consisting of a 

 few jointed hairs. 



20. DAVALLIA. (Named for M. Davatl, a Swiss botanist.) Many trop- 

 ical or sub-tropical species, the following cult, in conservatories. 



D. Canariensis, HARK'S-FOOT-FKRV, from the Canary Islands, etc. : 

 rootstock creeping above ground, covered with brownish scales, and looking not 

 unlike an animal's paw; fronds few, smooth, broadly triangular, 8' -15' long 

 and abuut as wide, 3-4-pinnate ; pinnules cut into a " few narrow lobes ; these 

 are directed upwards, bearing at or just below the end a single fruit-dot; indu- 

 sium whitish, deeply half-cup-shaped. 



D. tenuif61ia, from India and China : rootstock creeping, crisp with short 

 chaffy hairs; fronds smooth, 1- 2 high, broadly lanceolate, 3 - 4-pinnate ; 

 smallest divisions narrowly wedge-shaped, bearing at the truncated ends one or 

 two fruit-dots ; indusium brownish, mostly broader than deep. 



21. DICKSONIA. (For James Dickson, an English botanist.) The spe- 

 cies all but one tropical or in the southern hemisphere. 



D. puncti!6bula. Moist shady places, from N. Carolina N. : rootstock 

 creeping, slender ; fronds scattered, thin, minutely glandular, pleasantly odor- 

 ous, lancelote, long-pointed, 2 - 3 high, mostly bipinnate ; pinnules pinnatifid ; 

 the divisions toothed, each bearing a minute fruit-dot at the upper margin ; 

 indusium globular. 



D. antarctica. Tree-fern from New Zealand, a great ornament in large 

 conservatories: trunk 3' -5' thick, sometimes many feet high, bearing in a 

 crown at the top many fronds, 6 - 9 long, 2 - 4 broad, coriaceous, twice 

 pinnate ; pinnules oblong, acute, pinnatifid ; the oblong-ovate divisions bearing 

 1-4 rather large fruit-dots ; indusium prominent, plainly two-valved. 



22. CYATHEA. (Name from the Greek word for a small cup, referring to 

 the involucre.) Tree-ferns from tropical countries. 



C. arborea. Rareiy cult, from W. Indies : trunk sometimes 20 high, 

 stalk mostly light-brown, and without prickles or chaff; fronds 4- 10 long, 

 bipinnate ; pinnse 1 - 2 long, 6' - 8' wide, lanceolate ; pinnules narrowly lance- 

 olate, spreading, pinnatifid to the midrib ; lobes oblong, slightly serrate, with 

 4-9 fruit-dots near the midvein ; involucre beautifully cup-shaped, the margin 

 entire. Several other species, as well as one or two of the allied genus HEMI- 

 TKLIA (with an imperfect involucre, veins often partly reticulated), are rarely- 

 seen in conservatories. 



