62 Our yative Ferns. 



Tribe V. PTERIDE^. Sori marginal or intra-marginal, 

 provided witli an indusium formed of the reflexed margin of tlie 

 frond, and opening inwardly. 



* Terrestrial. 

 ^Sporan^ia borne on a reflexed portion of the margin of the 

 frond. 



VI. Adiantum, L. Sori usually numerous and distinct. Mid- 

 rib of the pinnules near the lower margin or wanting. 



\\Sporangia borne on a continuous vein-like receptacle which 

 connects the apices of the veins. 



VII. Pteris, L. Sori continuous. Indusium delicate, whitish. 

 Midribs of pinnules central. 



'^WSpOrangia at or near the ends of unconnected veins, borne 

 on the under surface of the frond. 



VIII. Cheilanthes.Swz. Sori minute at the ends of the veins. 

 Indusium continuous or interrupted. 



IX. Cryptogramme, R. Br. Sporangia on the back or near 

 the ends of the veins torming oblong or roundish sori, which are 

 at length confluent and cover the back of the pinnules. Sterile 

 and fertile fronds unlike, smooth. 



X. Pellaea, Link. Sori on the upper part of the veins, dis- 

 tinct, or mostly forming a marginal band of sporangia. Sterile 

 and fertile fronds usually similar, smooth. 



'"^Agnatic. 



XI. Ceratopteris*, Brong. Sori placed on two or three veins 

 which run down the frond longitudinally. Indusia meeting at the 

 midrib. 



Tribe VI. BLECHNE.ffi. Sori dorsal, linear or oblong, 

 borne on transverse veins, parallel to the midrib. Indusium fixed 

 at its outer margin, opening at the mner. 

 * Veins free. 



XII. Lomaria, Willd. Sori in a continuous band next the 

 midrib. Indusium elongated, formed of the recurved and altered 

 margin of the pinnae, or else sub-marginal. Fronds of two sorts, 

 elongated, pinnate. 



XIII. Ble:hnum, L. Sori linear, elongated, continuous near 

 the midrib. Indusia continuous, l-'ronds pinnate. 



*This anomalous genus is placed provisionally among tht- Ftn-kles, but it will prob- 

 ably demand a separate trilie for its reception. I*rof. Eaton placets it in a new sub unler, 



CER.\TOPTBRinE.>:. 



