12 PARTS OF FERNS. 



mass being called a " rootstock." Sometimes an erect rhizome or caudex becomes 

 flattened at the top and produces a great number of fronds, while at others it becomes 

 divided into two or more branches, each of which produces a separate crown ; and 

 occasionally fresh crowns burst out of the side of a caudex. It is not quite certain 

 how these originate. In some cases it appears to be the nature of the fern to divide 

 itself in this fashion ; in others, it seems as if young plants had grown on the face of 

 a caudex ; while in others it occurs by accident. I watched a case where a falling 

 tree strained a supplejack tightly across the crown of a tree fern ; with the result that 

 the next spring the plant produced two crowns, one on each side of the supplejack, 

 and thenceforth was forked. I have seen a cyathea dealbata with five branched caudices 

 and crowns, and an aspidium aculeatum with seven, varying from three feet to five 

 feet high. In the Philosophical Transactions for 1886, there is a drawing of a 

 Hemitelia Smithii with sixteen crowns ; and Mr. Buchanan, who met with it, mentions 

 that many others near it were much branched. Sometimes one form of a fern exhibits 

 this tendency to divide itself, while the others do not, or do so in less degree ; and 

 when it occurs, the several crowns may be separated and grown as distinct plants, 

 when they will probably again divide. 



In other cases, the rhizome creeps along, sending out single fronds as it goes. 

 Sometimes these fronds form a single row and at others two or three. In some ferns, 

 as in most of the Hymenophylla, it is a mere wiry thread from which similar ones 

 branch out right and left at intervals, till the ground or tree on which the plant occurs 

 is covered with an interlacing mat, the fronds from which clothe the whole surface. 

 Sometimes these creeping rhizomes are thick and fleshy, and in some cases, as 

 Polypodium Billardieri, are often half an inch in diameter ; and in Pteris aquilina (the 

 N.Z. bracken) even thicker ; and though more or less fibrous, so full of starch that 

 they formerly supplied the Maoris with a very large portion of their food. Some of 

 them climb like ivy, holding on by their roots, and in this way ascend to great heights 

 on our tree-trunks, which they clothe with fronds. In some cases, the fronds from 

 creeping rhizomes spring up at considerable intervals, while in others they grow so 

 close together that the whole plant, till carefully examined, may be supposed to be a 

 tufted one. In this last case, the rhizome itself creeps but little and slowly. Some- 

 times one form^ of a fern will creep -rapidly and another very slowly ; and as this 

 difference is usually accompanied by some difference of foliage, it may be questioned 

 whether the two forms should not be separately classed. Sometimes a creeping 

 rhizome, instead of sending up single fronds at intervals, sends up erect rhizomes with 

 crowns of fronds on each ; and these again occur sometimes at long intervals and 

 sometimes so close together as to make the plant appear to have merely an erect 

 branched rhizome. 



In one case (Marattia fraxinea), the rhizome is a large fleshy tuber with fleshy 



