54 DT7BLIN NATTTBAL HISTORY SOCIETY. 



form monstrosity, and sub-variety, a monstrosity not necessarily permanent nor 

 uniform— ex. gr. in Lomaria spicant, var. cristatum* every frond each year dicho- 

 tomously rounded at the apex, while Lom. spicant, subvar. mullifidum, though 

 much resembling it in general character, has some years all the fronds dichoto- 

 mous ; other years, perhaps, a single frond dichotomous } and other years none at 

 all— in fact, in this the great difference consists between the two divisions ; in 

 the first, the monstrosity depending on some radical change in its nature, once 

 imprinted on the plant, is nearly indelibly so, extending often even to the pro- 

 duce of the spores (as w6 see in some monstrous forms of Athyrium) ; while in 

 the sub-variety, the monstrosity depending on some mere loc{j,l or climatal in- 

 fluence is liable to change as these are modified or removed. It is not meant to 

 be asserted that varieties will not sometimes change under cultivation into ano- 

 ther seemingly different variety, or that the spores will not produce plants of 

 the normal type, but that this much may be taken as proved — that variety never 

 changes into subvariety, or subvariety into variety ; therefore, the statement 

 put forward, to the effect that variety cristatum is but a form of sub- variety 

 multifidum, is based on error. Another grand distinction between the two, in a 

 state of nature, is, that seldom or ever do we find the variety in more than one 

 or two plants at most, while the sub-variety is often found more or less pervad- 

 ing the plants of a district — ex. gr., there is a little stream glen at the base of 

 the greater Sugarloaf, where L. spicant, subvariety multifidum, may always be 

 found, some years every plant bearing fronds more or less divided ; in other years 

 you will only get single plants so affected; while the variety cristatum was found 

 affecting only a single plant. The same might be said of the variety cristatum, 

 and sub-variety multifidum of Ath. incisum ; and all varieties found in collections 

 will be found to have had their origin from a few isolated plants found in various 

 localities. There are some characters, the uniformity of which, of primary im- 

 portance in considering genera and species, are but secondary in considering va- 

 riety — such as character of venation, division of frond, fertility ; these are va- 

 riously modified, according to the type of variety or sub- variety, and, of course, 

 to a certain extent, modify it in return. More generally we find the variety bar- 

 ren than the sub- variety, but this may arise from some mistake of manipulation in 

 cultivation. Indeed, for my own part, I believe most varieties may be made to 

 produce fertile fronds, at least in the two forms under consideration to-night. 



All the groups thus formed are capable of general definitions, though it must 

 not be expected that this general definition will detail every minute feature of 

 variety found in the many analogous forms necessarily included under it, any 

 more than the definition of species describes every minute feature of the indivi- 

 dual plants comprised, these being of little importance, provided the general 

 characters are adhered to. To each of these groups a name is proposed to be 

 given, by which it may be known, so that, for most species, it will suffice to 

 quote this name to show what the form of the variety is. When two or more dis- 

 tinct forms of the same variety occur under a species, it will be but necessary to 

 mark them in some way, as with Greek letters, &c., after each, and describe the 

 salient points of difiFerence. Ex. gr., under Ath. Filix faemina, we find three 

 forms of a variety which we will call cristatum; these could be thus described — 

 Ath. Filix fsemina, var. cristatum (three forms). 



A, rachis branched; pinnules decurrent; apices of segments curled. B, ra- 

 chis split into numerous linear segments ; pinnae contracted ; apices of pinnae 

 split into linear segments, tasselled. r, rachis and pinnae multifidly crisped at 

 apices, and tasselled. This is the only species in which the forms of this variety 

 cannot be referred to one description, and when the species of Athyrium are de- 

 finitely arranged, possibly the forms will be found to belong to different species. 

 (^Vide second part of paper.) To enter into all the sub-varieties and varieties 

 would detain you too long. I shall, therefore, content myself with one of each, 



* This name is inibstittited for Ramostun at the sugfi^cstion of my friend, G. B. Wollaston. 



