A NEW FORM OF FERN REPRODUCTION 359 



A NEW FORM OF FERN REPRODUCTION. 



By Chas, T. Dkuery, V.M.H., F.L.S. 



In recent years the normal course of fern reproduction has been found 

 in exceptional cases to be replaced by many variants, so many, indeed, 

 that every one of the various phases of the life-history of a fern has 

 been found wanting, even to the very fronds which represent the fern 

 as we know it. The missing phases are due, as it were, to jumps from 

 one phase to another, which normally would require one or more inter- 

 mediate ones. Thus, to take an extreme case, the normal course of fern 

 production by the spore is the spore which grows into a prothallus, or 

 little green scale, which then bears two kinds of organs beneath it, one 

 of which fertilises the other and produces what is to all intents and 

 purposes a seed. This seed then germinates and produces a fern, upon 

 the fronds of which the next series of spores is borne. The extreme 

 short cut is that the little green scale produced by the spore produces 

 spores direct, and another short cut on different lines is seen where 

 the fern fronds bear the green scales at their tips, and these green 

 scales bud apogamously direct into ferns again. But, so far, all these 

 peculiarities have occurred in connection with varietal forms of ferns 

 or sports, in which, however, although the fronds have been modified 

 in make, they have been of ordinary size, and subject to the specific 

 deciduous or non-deciduous nature peculiar to the family. Furthermore, 

 they were only locally modified either at their tips or at the backs, where 

 spores normally are borne. In the new case, however, which came under 

 my notice in the late summer of 1904 some entirely fresh features 

 presented themselves. A small piece of normal Cystopteris montana, 

 of which species no varieties are recorded, was sent to me from Scotland 

 in 1903 somewhat late in the season. The result was that it apparently 

 perished, and in the subsequent spring I was emptying the little pot 

 when I detected a minute green speck, indicating vitality, and consequently 

 repotted it, with the result that during the summer it sent up two small 

 normal fronds. In July I noticed that at the base of one of these, on 

 an exposed portion of the creeping rhizome, a cluster of very small short 

 stalked fronds were forming, differing altogether from the normal ones 

 in being very thin and translucent, with veins of a much more indefinite 

 character, and in addition to the very short stalks (the normals have very 

 long ones) they were only pinnatifid, i.e. scarcely once divided, each 

 frond of the half-dozen being of the same size (about half an inch long), 

 only with two or three blunt lobes on each side. They thus presented 

 no resemblance whatever to the accompanying normals, which are tripin- 

 nate ; and had it not been perfectly clear that they sprang from the 

 rootstock direct, I should have taken them for another fern entirely, 

 though they resembled none known to me. Their peculiar thinness 

 and translucency led me, in view of my experience with aposporous ferns, 



