1898,] Prakgkr. — Fructification of Ferns, ^c. 113 



are figured. Many of the specimens which I collected there 

 bore several fertile branches, as shown in fig, 2. These recall 

 some of the foreign Adder s-tongues, such as the O. pal^nattcm 

 of South America, which normally bear a number of fertile 

 branches springing from near the base of the blade or 

 expanded portion of the barren branch. In a number of 

 others the fruiting-spike was twisted on its axis, as is shown 

 in fig. 3, the result of the undue growth of one side ; and in 

 the interesting specimen shown in fig 4, one side of the fruit- 

 spike had actually grown out into a leafy expansion resem- 

 bling in structure the barren frond. This accidental sport 

 shows the afiinity of the barren and the fertile branches, which 

 are so different in appearance. They are no doubt derived 

 from a common ancestral form. The one has become 

 expanded, barren, to carry on to most advantage the process 

 of food-making : the other has been reduced to a narrow erect 

 axis, where the spores may most conveniently be matured and 

 dispersed. The variety polyphylhim is distinguished by 

 bearing one or even two additional barren fronds on the same 

 root-stock. 



The Moonwort, Botrychiuni Lmiaria, resembles the Adder's- 

 tongue in the relation of the barren and fertile fronds, but 

 differs in that both are divided. The barren frond is pinnate, 

 with fan-shaped segments more or less cut. The fertile frond 

 is twice pinnate, and the brown spore-cases cluster on the 

 branches somewhat as they do in the Royal Fern. Sports are 

 rare, but not so rare as in the Adder's-tongue. Those that 

 occur often display a certain symmetry. Thus a small fertile 

 frond will be borne on each side of the normal one, from the 

 point where it springs from the barren frond (fig. 5). Or a 

 pair of small additional barren fronds will arise from the same 

 point. Or, as in another specimen in my herbarium (fig. 6), the 

 lowest pair of pinnae of the barren frond will be themselves 

 pinnate. I have never seen the fertile frond display any of 

 the leafy growth that characterizes the barren frond, but the 

 converse may be occasionally observed, and spore-cases be 

 found placed on the margin of some of the fan-shaped seg- 

 ments of the barren frond, as may be observed in the lowest 

 left-hand pinna of the specimen figured in fig. 6. This shows 

 clearly the close relationship between the two kinds of fronds, 

 so different in appearance, 



