14 ACROGENS. 



fronds large, in a crown at toij. 4 gen. ; 151 spec. ; tropics. 1. Cya- 

 thea. Fronds 1-3-pinuate. Many fine species, tropics of both worlds. 

 C. arbbrea. Frontispiece, B. Section of stem, Fig. 42. S. Am. 

 2. Alsophila excelm, 80° high ; Norfolk Island. A. Perrotetidna, 

 30° high. W. Ind. 3. Hemit^lia speaidsa. W. Ind. 4. Matonia 

 pecUndta, only genus and species ; no caudex. Ehiz. creeping, bear- 

 ing a single frond on a tall ebony leaf-stalk ; frond fan-shaped, dichot- 

 omous, each leaf pinnate-pinnatifid. Tropics. 



Tribe 8, Polypodiacese. — King incomplete, vertical. Sporangia 

 pedicelled. Sori often indusiate. 50 genera ; more than 1000 species. 

 1. Dicksonia antdrctica, caudex tall, crowned with 2-pinnattf fronds 

 6°-9° long. New Z. D. punctiUbula, Sweet F. Rhiz. creeping; 

 fronds scattered, lanceolate 2-pinnate, 2°-3° high, fragrant. N. (J. 

 and Tenn., N. ; moist shades. 2. Cibotium. Ehiz. decumbent, 

 shaggy with fine hairs ; fronds of Dicksonia. C. Barometz [glau- 

 cescens), Agnus Sct?thicus, Scythian Lamb, Byssus. West Asia. 

 See Lesson VII. C. glaitcum, C. Chamissoi, C. Menziisii, PtiLtr 

 Ferns. Sandwich Islands. See Lesson VII. 8. DavSllia. Ehiz. 

 creeping above ground, scaly ; fronds pinnately decompound, rarely 

 pinnate. D. acuUdta, scandent, bramble-like ; S. E. Asia. D. cana- 

 riensis, Hake's-Foot F. ; rhiz. .creeping, resembling a hare's foot ; 

 fronds few, triangular, 15' in size, 3-4-pinnate. Canaries. 4. Wood- 

 sia. Small, tufted ; frond lanceolate, pinnate. W. Ilvensis, 4'-8' 

 high ; W. obiiisa, 6'-18' high. N. C, northward, mts. 5. Onoclea 

 sensibilis. Sterile frond pinnate, triangular, l°-2° high ; fertile con- 

 traeted, fiower-like. Damp places, TJ. S. 6. Struthiopteris, Ostkich 

 Fkrn. Caudex erect ; .fi-onds erett in a crown ; sterile lanceolate, pin- 

 nate-pinnatifid, 2°-5° high, in an outer series; fertile in the centre, 

 much shorter, pinnate, pinnae contracted, moniliform. S. germdnica, 

 Northern U. S 1 species in Eur. ; 1 in Asia. 7. Cystbpteris, Blad- 

 der F. ; indusium inflated. C.frdgilia, fronds delicate, 4'-8'' long, 

 oblong-ovate, 2-pinnate. Eocky shades, N., U. S. C. bulbifera, 

 fronds lanceolate, l°-3° high, 2-pinnate, bulbiferous beneath. Wet 

 places, N. C, N. 8. Cyrtomium. Indusium peltate ; veins netted, 

 venules curved. C. falcdtum, frcmds evergreen ; pinnate, lanceolate, 

 l°-2° high, end pinna large, rhomboid. Japan. 9, Polystichum. 

 Indusium of 8 ; veins free. P. acrosticholdes, fronds evergreen, lance- 

 olate, pinnate, bristly-serrulate, l°-2° high, in crowns. Eocky woods, 

 U.S. 10. Aspidiutn. Shield F. Indusium of 8 and 9 ; but veins 

 compoundly reticulate. Strong-growing, usually pinnate ferns. 12 

 , species, in Asia, S. Am., W. Ind. None in U. S. A. aingaporidnum 

 has simple fronds. Singapore. 



11. Lastraea. Indusium reniform ; veins free. 2 Sections : 



1. Fronds evergreen, in a crown. 

 L. margindle ; fronds 2-pinnate, ovate-oblong, l°-3° high. Eocky 

 grounds, IT. S. L. FUix-mas, Male F. ; fronds 2-pinnate, lanceolate, 

 3° high. Eur. ; adv. in Canada ; found in Tennessee. L. apinulbsa, 

 fronds oblong-ovate, 2-pinnate, l°-3° high, spinulose. N., IT. S. L. 

 criatdta, fronds lanceolate, pinnate, l°-2° high, pinnae pinnatifid, ser- 

 rate. Wet woods, U. S. L. Ooldidna, fronds broad ovate, 2°-4° high, 

 pinnate, pinnae pinnatifid. N., U. S. L. Siebildii, frond thick, ]° 

 high, with 5-9 large pinnae, end pinna largest. Japan. 



