48 DUBLIN NATURAL HI8T0EY SOCIETY. 



of the scientifio student, and yet, morphologically considered, they are most in- 

 teresting, not to say important; often tending to throw light on obscure points 

 in the economy of species. Furthermore, when such men as Sir Charles Linne 

 Willoughby and Ray deemed them not below their notice, surely they are not 

 beneath ours. To obviate these inconveniences, I beg to propose the following 

 plan : — Let all descriptions of forms of ferns be divided under the following four 

 heads:— i.e. First — Form or original type; second, Sub-form, or forms aber- 

 rant from some geographical influence, such as climate, &c.,and including what 

 are called doubtful species ; third, Sub-varieties, or non-permanent monstrosi- 

 ties ; and, fourth, Varieties or permanent monstrosities. Between these last we 

 shall find some very strange analogies, the sub-variety often appearing as 

 though it were but a link between the variety and original form. 1 say appear- 

 ing, because they never, at least as far as I can find, degenerate into one another ; 

 when any change does take place, the sub-variety returning to the original type, 

 and the variety either degenerating into some other variety, or else also return- 

 ing to the original form. To meet the last inconvenience I would suggest, that 

 to each sub -variety, variety, and sub-form, no matter in how many species 

 found, but one distinctive name be given, defining that name as species and ge- 

 nus are at present defined; so that, when we find this form under any species, 

 we need but to the specific and generic names append this distinctive name, in 

 order to render the identification of it easy, and thereby save ourselves from the 

 trouble of repeating with every species a probably long description. The 

 sub-forms would include all forms of the fern departing in a slight degree from 

 the original type, so as to present tangible differences, and yet approaching it 

 sufficiently near to be identified with the species generally prevailing through 

 the entire plants of a district, often returning to the normal form under cultiva- 

 tion, and bearing spores which produce plants similar to the original type — this 

 class will include many at present so called doubtful species. Variety would 

 include monstrosities, i. e. aberrant forms, or plants in which the origi- 

 nal form of the species is lost entirely or in part, so as to render identification 

 difficult, found generally in isolated plants, generally permanent under cultiva- 

 tion, uniform, i. e. affecting all fronds of the plant, if fruitful, generally pro- 

 ducing plants similar to the parent. Sub-variety, i. e. aberrant forms not 

 permanent under cultivation, always retaining in a great degree the original 

 type, not uniform, nor necessarily affecting the same plant every year, even in 

 a state of nature, and from its spores generally producing the normal form. In 

 accordance with these views, I have succeeded in classifying under the following 

 four heads, all the monstrosities described by authors, as well as many hitherto 

 undescribed. These classes and their distinctive characters I now hasten to lay 

 before you in the following order, using the terms Variety and Sub- Variety in the 

 sense I stated just now, I shall describe each analogous variety and sub-variety 

 together, not that I believe there is any necessary connexion between them, for 

 the reasons stated before, but merely for convenience sake. To the first sub- 

 variety I propose to give the name Multifidura, taking as its type the common 

 hart's tongue, var. multifidum, and including under it those forms in other spe- 

 cies to which the names Bifidum, Lobatum, Ramosum, have been given. With 

 these I propose to join, as the analogous variety, the form Ramosum, taking as 

 its type the common hart's tongue, var. Ramosum, and incorporating under it 

 those varieties to which the names crispum, viviparum, multifidum, furcatum, 

 diedalea, &c., have been by various authors given. The definitions of these two 

 will be as follows: — Ramosum, variety; Rachis, divided and sub-divided; seg- 

 ments rounded at their edges and apices, generally curled and crisped, mid- vein 

 terminating in a lash of branches, segments confluent at their edges. Next, the 

 variety which, taking the common polypody variety cambricum as the type, I 

 propose to call Cambricum ; it will include the varieties called Incisum, Poly- 

 schides, and Strictura. The allied sub-variety taking the analogous sub -variety 

 of the same fern, sinuatum, I propose to call Sinuatum ; it includes serratum, 

 proliferum, &c. These two 1 define as follows : — Cambricum, variety — Frond, 



