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following iindescribed forms : — Male shield-fern, var. Cambricum, sub- 

 var. sinuatum, mihi (common on most rich banks) ; Roth's fern, sub- 

 var. sinuatum, raihi (Ardmore, in dry situations) ; scaly Grammitis, 

 subvar. sinuatum (mihi), Gort. ; hart's-tongue, subvar. sinuatum, 

 mihi (Clare) ; angular shield-fern, var. described by me as viviparum, 

 in June, 1852, before this Society. These four forms include all the 

 true varieties which I have met with, except one form of the hart's- 

 tongue, viz., undulatum, which may, I think, be referred to the form 

 Cambricum, and is a degenerated form of ramosum. Subforms, owing 

 to a difficulty in procuring specimens, I have not been as successful 

 in reducing to classes ; though that it can be done I doubt not. I 

 shall content myself, therefore, with laying one before you, which I 

 propose to call abbreviatum ; taking as its type the form of the male 

 fern to which that name has been given. This we find represented in 

 the following species, and define as follows: — Abbreviatum. Subform : 

 Frond contracted in all its parts regularly, the pointed outline of the 

 frond retained. Examples : Polypody of the oak, subform acutum, 

 Newm. (Youghal) ; male shield-fern, subform abbreviatum, Moore 

 (England) ; prickly shield-fern, subform lonchitidioides (Clare and 

 Ulster); angular-lobed shield-fern, subform abbreviatum, mihi (county 

 Wicklow) ; wall-rue spleenwort, subform abbreviatum, mihi (county 

 Clare) ; hart's-tongue, subform angustifolia, Auct. (Killaloe) ; lady- 

 fern, subform abbreviatum, mihi (Ardmore). I doubt not but other 

 forms might be referred to this class ; e. g., black-stalked spleenwort, 

 var. obtusum, Newm., brittle bladder-fern, var. dentata, &c. ; but suf- 

 ficient are quoted to show what I mean. Similarly, I doubt not, 

 most, if not all, the following might be included under one common 

 class : — Incisa, male fern, var. erosa, Deakin, incisa, Moore ; black- 

 stalked spleenwort, var. acutum, Newm. ; brittle bladder-fern, vars. 

 cynapifolia and anihriscifolia, &c., and numerous others, which, as 

 I do not possess specimens of them, had, perchance, better be passed 

 over. 



"This is a general outline of the system proposed to be intro- 

 duced. That it is not an unnecessary one will be evident, if we 

 consider the number of these varieties which every day's research 

 brings to light, and the consequent number of descriptions which 

 must be introduced for them into our Floras, the greater part of which 

 may be avoided by pursuing the plan now sketched out. I think the 

 same plan might be pursued in general Botany, with a good effect ; 

 but it is of far greater importance in Filicology, as so many of this class 

 of plants may be recognized by their external form alone. Before 

 VOL. IV, 6 R 



