Seed-vessels of Ferns, and Section of Limestone. 



Plate 3. 



10 



I. Seed-vessel ot Fern when unripe, magnified 60 diameters. 2. Seed-vessel of Fern, at the 

 moment when the ring straightens itself. *. Leaflet of black Maidenhair Spleenwort Fern. 



4. Two sori, or collections of seed-vessels, of Spleenwort Fern, magd. 12 diams. 5. Sorus of 



Huit's-tongue Fern, magd. 6 diams. 6. Part of a leaflet of Shield Fern. 



7. Sorns, magd. 10 diams. 8. Sori of Polypody Fern, magd. 7 diams. 9. Sori and part of 



leaflet of Hare's-foot Fern, magd. 5 diams.' 10" Thin section of Limestone, magd. 20 diams. 



II. Group of twenty seed-vessels, natural size. 1:'. Group of twenty seed-vessels, magd. 6 diams. 



13. Leaflet of Polypody. 14. Part ol a leaflet ol Haie's-foot Fern. 



