56 PROCEEDINOS OF THK 



cesses toriniiiating in prothalli, or, more rarely, veinlots near the 

 extremities of the pinnules were extruded, their tips then ex- 

 pandinfj into club-shaped protuberances wliich bore root-hairs 

 and arehegonia even prior to their subsequent assumption of the 

 in'otliallus-form by the expansion of their extremities. Professor 

 Bower furfhcrmore observed that the apparently abortive sori 

 which were produced upon tlie Polystichmn were also capable 

 under culture of developing prothalli here and there from the 

 sporangium-stalk, though these were of imperfect character, the 

 reproductive energy being very feeble in this direction, so much 

 so, indeed, that careful microscopic scrutiny was needed to detect 

 the phenomenon at all. Both forms of the Polystichum displayed 

 all three characters, a singular fiict considering their manifestly 

 independent origin. 



The fresh discovery which I now desire to place on record is 

 due to Mr. F. W. Stansfield of Sale, near Manchester, who is in 

 possession of a third form of P. a » r/idare vav. j^nlcherritnum ioxind 

 by Mr. Moly in Dorsetshire, and very simihir in character to tlie 

 others. This plant, however, tliough found some years ago, has 

 never been observed to bear the apical form of apospory ; but, 

 strange to say, this season upon two fronds it had developed 

 the soral form of that phenomenon in almost precisely the same 

 fashion as Alhi/rium Filix-foemina var. chirissima. Naturally, 

 however, the inasses of pseudo-prothalli are round instead of 

 oblong, due to the specific differences between the sori of the 

 two plants. The grow^th appears also to be more robust, one 

 consequence of which is that here and there, among the slender 

 clavate forms through which the aborted sporangia pass to the 

 prothallus-shape, there may be seen much larger irregularly- 

 formed bodies precisely akin to the peai'-shaped pseudo-bulbils 

 which led to the discovery of the phenomenon on Athi/riinn Filix- 

 fosminn var. clarissima in the first place, but which have not 

 reappeared. This additional robustness also leads to the pro- 

 duction of obvious prothalli even before the pinnre are laid down 

 for culture, a fact which drew Mr. Stansfield's attention to the 

 phenomenon. It is of interest to know that this plant is only 

 semi-constant, a proportion of normal fronds being intermixed 

 with those typical of the variety, and upon these normal fronds 

 Mr. Stansfield informs me nornial spores are produced. 



In a former paper I hazarded the theory that the abnormal 

 slenderness and elongated character of the portions of the Ferns 

 which develop ai)ospory were correlated with that phenomenon, 

 and 1 think that the last-mentioned fact materially strengthens this 

 view, especially when it is borne in mind that even on the typical 

 fronds o}i the jmlcJierrimuin varieties the upper pinnules on each 

 pinna are nearly normal, and upon these the apical ])rothalli are 

 far more sparingly produced than upon the long slenderly-falcate 

 and divided pinnules which form the lower part of the pinnae. 

 A. FUix-fwmina var. clarissima is also very slender in all its parts^ 



