PREFACE. 
Xlll 
intermediate stages between it and L. dilatata were to be 
observed, would fully justify its claim to be a species. 
The various divisions of the lamina in the same species, 
by which a frond, imperfectly pinnatifid, becomes pinnate, 
bi-and-tripinnate, f. 5, G, 7, constitute marked varieties in 
Fig. 5. Fig. 6. Fig. 7. 
the character of the same species, and materially alter 
— especially when accompanied by diversities in the margin 
of the lamina, whether it be rounded, sinuate, serrate, jagged, 
lobed, or capilliform — the aspect of the whole plant. The 
accompanying figure of a variety of Athyrium filix-foemina, 
