DUBUN NATURAL HISTOBT SOCIETT. 63 



JUNE, 1854. 



BSCORD OP ATH. FILIX FiEBUM A, VAR. LACIMIATDM. 



Dr. Kinahan exhibited a beautiful form of Athyrium filix>foemina, Newman, 

 obtained in June, 1854, near Castlekelly, county of Dublin. In it the segments 

 of the pinncB are pinnatifid ; the indentations entire at their edges, and beariofl^ 

 the sori in the angle ; the spore-cases projecting beyond the edge of the fron^ 

 which, added to the bulging forwards of the substance of the pinnule, giret the 

 plant much the appearance of a Davallia, or rather of a Loxsoma, thoueb, of 

 course, differing in the shape and position of the indusium from either of these 

 genera. In habit, this plant resembled Athyrium cicutarium, especially in the 

 remarkable fact of its segments bearing but a single vein and sorus, thus corro- 

 borating the illustrious Robert Brown's opinion, who rejects this as a distinctive 

 character, in opposition to Smith and Bernhardi, by whom the genus Darea or 

 CsBnopteris has, owing to this character, been separated from Athyrium. Thif 

 plant IS also a beautiful example of the variety laciniatum (Kin.). The plant was 

 growing in a shady nook along with a plant of the ordinary form. It is sparingly 

 fruitful. 



APRIL 7, 1854. 



ON THE ABNOBMAL FOBMS OF FERNS. — PART I. B¥ J. R. KIMAHAM, M. B. 



When, on a previous occasion, I called the attention of this Society to the 

 subject of abnormal forms among the ferns, I statedmy suspicion that some ge- 

 neral law or laws would be found governing them in their entirety, as a class, 

 and thereby enabling us to group them. I then laid before you a sketch of the 

 groups into which, in conformity with these supposed laws, forms might be di- 

 Tided. This scheme, crude at that time, has, thanks to the contributions of spe. 

 cimens by friends, and additional opportunities of examination afforded to my- 

 self, since been confirmed in most or its details, so that the following may be set 

 down as established : — 1st. That the aberrant forms of ferns obey certain fixed 

 laws of form. 2nd. In accordance with these laws, that they may be divided 

 into two great groups, bearing certain relations to each other, similar, and yet 

 perfectly distinct. 3rd. That these great groups may be subdivided into pa- 

 rallel sub-groups, each sub-group in the one representing a sub-group in the 

 other, totally irrespective of generic or specific distinctions. To examine and 

 illustrate these laws will be my task to-night. First, a few words to remove a 

 misapprehension which I find many labour under with regard to former remarks 

 made on this subject. It is not the object of this scheme to establish new spe- 

 cies—far from it ; with species, as such, it has nothing to do, solely dealing with 

 the morphology of the plants under consideration, totally irrespective of species 

 or genus. 



These two great classes, as was before stated, possess strong analogies both to 

 one another and within themselves, yet are perfectly distinct, never running into 

 orproducing one another, though we may find a group of the one class in acciden- 

 tal combination with one of the other. These two groups, for which I proposed 

 the names, variety and sub-variety, will be found to possess the following dis- 

 tinctive characters: — Variety is universally a permanent aberrant form, affect- 

 ing all the fronds of the plant — i. e. uniform ; under all circumstanees of culti- 

 vation preserving its distinctness, and occurring generally in isolated plants ; if 

 fruitful, often producing its own form. Sub-variety, an aberrant form, seldom 

 permanent unaer cultivation, affecting only a few fronds, often occurring in nu- 

 merous plants of a district, and from its spores producing the normal form — this 

 is sometimes permanent under cultivation, but never uniformlvso. The essential 

 difference between these two classes, then, in brief, is — variety, a permanent, oni- 



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