340 Observations on the Germination of Ferns. 



by Turpin. And the inference is perfectly convincing that in ferns 

 (and the mode of reproduction is the same in mosses and Equiseta) 

 there is no impregnation ; and if this be true of the plants just men- 

 tioned, the argument will be so much the stronger as regards the 

 lower cellular plants. 



List of References, Plates XI. XII. 



1. Nephrodium marginale 10 days after sowing; b, b, more highly 

 magnified, shewing the separation of the integument into two 

 halves ; c, c, c, Gymnogramma rufa 19 days after sowing. 



2. Nephrodium marginale after 16 days, b the same much magnifi- 

 ed. 



3. ■ 22 days, b much magnified. 



4. 4 weeks and 3 days. 



5. 6 weeks and 2 days. 



6. ■ 2 months. 



7- ■ 5 months. 



4, 5, 6, and 7 are magnified considerably : the latter has attained 

 its full size, and is on the point of producing the first gyrate frond. 

 In all cases, the first formed cellules either decay or are drawn un- 

 der the earth by the fibrils, before the primary frond arrives at the 

 state of No. 7- 



8. A portion of a lobe of Gymnogramma chrysophylla highly mag- 

 nified, exhibiting the manner in which the cellules are connected. 



9. Lower surface of part of a primary frond considerably magnified, 

 with the large cellules which form the basis of the cellular knot. 



10. 11. Asplenium monanthemum, lower surface, showing the posi- 

 tion of the cellular knot. 



12. A reniform primary-frond of an unnamed fern. 



13. Pteris nemoralis with the radicle protruded, and the first gyrate 

 frond partly developed. 



14. A portion of the primary frond of Pteris nemoralis, more high- 

 ly magnified, the lobes folded back, showing the position of the 

 gyrate frond and root on the cellular knot, and its attachment to 

 the primary frond. 



15. Aspidium fraxinifolium, the first gyrate frond fully developed. 



16. Gymnogramma tartarea, the first gyrate frond a palmate or lob- 

 ed leaflet, the second arising from its base. 



17. Asplenium monanthemum, the first gyrate frond a simple leaflet, 

 the second partly developed, lobed at the apex. 



18. 19, 20. Portions of the primary-fronds of three species of ferns, 

 exhibiting the progress of the cellular knot. 



