136 



KEY TO THE FAMILIES AND GENERA 



BB. Sterile Iva. with anastomosing veins: sori 

 interrupted. 



c. The sori sunken in the Ivs 33. Woodivardia. 



cc. The sori superficial in 1 or more rows 34. Doodia. 



AA. Sori partly parallel and partly oblique to the 



midrib: veins anastomosing 35. Camptosorus. 



AAA. bon oblique to the midrib. 



B. Veins free, united at the margins. 



c. The sori double, extending along both 



sides of the vein 36. Diplazium. 



CC. The sori single on the veins. 



D. Indusia opening toward each other, in 



pairs 37. PhyUitia. 



DD. Indusia all opening toward the end of 



pinnae or segms 38. AspUnium. 



BB. Veins of lower (inner) series uniting: indu- 



sium extending both sides of veins 39. CaUipteris. 



6. Dryopteris Tribe. 



A. Indusium present. 

 B, Veins free, or with a single row of areoles 



along the mid-veins. 

 c. Indusia on the ends of veins which project 



beyond the margin of the If 40. Deparia. 



cc. Indusia dorsal. 



D. The indusium cordate or reniform, 

 attached by the sinus, sometimes 



wanting 41. Dryopteris. 



DD. The indusium orbicular, peltate, at- 

 tached by a central stalk 42. Polyatichum. 



DDD. The indusium oval, fixed to a central 



elongate receptacle 43. Didymo- 



BB. Veins anastomosing. [chlxna. 



c. The indusium cordate or reniform, 



attached by the sinus 44. Tectaria. 



cc. The indusium peltate, attached by a 

 central stalk : veins forming small 



areoles 45. Cyrtomium. 



AA. Indusiam wanting. 



B. Veins free 46. Phegopteris. 



BB. Veins anastomosing. 



c. The main veins joined by arches which 



bear the curved sori 47. Gymnopteris. 



cc. The son round, attached dorsally. 



D. Sori distinct at maturity 48. Meniacium. 



DD. Sori confluent at maturity 49. Leptochilus. 



7. Davallia Tribe. 



A. Indusium attached at base only. 

 B. Pinnae jointed to the rachis; Ivs. simply 



pinnate: indusium circular or reniform. . .50. Nephrolepis. 

 BB, Pinna- not jointed to the rachis; Ivs. jointed 

 to the rootstock 



c. The indusium thick, coriaceous 51. ffumota. 



cc. The indusium membranous 52. Lcacostegia. 



AA. Indusium attached at both base and sides. 

 B. Lvs. jointed to the scaly rootstocks. 



c. Shape of indusium tubular 53. Dacallia. 



cc. Shape of indusium broader than long, 

 forming a boat-shaped cavity on the 



edge of the segm 54. Lozoscaphe. 



BB. Lvs. not jointed to the rootstocks. 



c. Indusia near the end of unmodified lf.- 



lobes, 



D. Sorus formed on receptacles contain- 

 ing vascular tissues 55. Microlepia. 



DD. Sorus not formed on a special receptacle.56. Odontosoria. 

 CC. Indusium united with the modified lf.- 



lobe to form a complete cup 57. Dennstxdtia, 



8. Woodsia Tribe. 



A. Lvs. uniform, plane; veins free. 

 B. Indusium beneath the sorus, breaking up 



into linear lobes 58. Woodsia. 



BB. Indusium extrorse, opening laterally with a 



hood-like lobe 59. Cystopteris, 



AA. Lvs. dimorphous, the sporophylls clo.sely 

 rolled together. 



B. Veins free: Ivs. in crowns 00. Matteuccia. 



BB. Veins anastomosing: Ivs. scattered 61. Onoclea. 



Brainea, Compteris, and Lonchitis are briefly described. 



219. GLEICHENIACE.E. 



Single genus in cultivation Gleichenia. 



220. CYATHEACE^E. 



A. Sori borne on the apex of the veins: 

 indusium extrorse, formed of a more 

 or less modified marginal tooth and 



an inner lid-like scale 1. DICKSONIA TRIBE. 



AA. Sori borne dorsally on the veins or at 

 the fork : indusium inferior, or 

 wholly wanting 2. CYATHEA TRIBE. 



1. Dicksonia Tribe. 



A. Tooth of spore-bearing segm. scarcely modi- 

 fied, about the size of the inner scale 1. Dicksonia, 



AA. Tooth of the spore-bearing segm. strongly 

 modified, coriaceous like the inner scale and 

 usually larger 2. Cibotium. 



2. Cyathea Tribe. 



A. Indusium present, inferior. 

 B. The indusium at first inclosing the globular 

 sorus, remaining cup-shaped or irregu- 

 larly splitting at maturity 3. Cyathea. 



BB. The indusium membranous, semi-circular, 



more fully inclosing the sorus 4. Hemitelia. 



AA. Indusium wanting 5. Alsophila. 



Thyrsppteris, of another tribe, may be expected in cultivation 

 and is briefly accounted for in this work. 



221. CERATOPTERIDACE.E. 



Habit aquatic: single genus Ceratopteris , 



222. SALVINIACEJE. 



A. Lvs. minute, numerous, closely imbricated: 

 sporocarps of 2 kinds, the larger globose, the 



smaller ovoid 1. Azolla. 



AA. Lvs. larger, fewer, distinct: sporocarps uni- 

 form, globose 2. Sahinia. 



223. MARSILEACE^. 

 In cultivation Marsilea. 



