152 PROCEEDINGS OF SOCIETIES. 



their distribution, often crossing one another in their course ;• generally fruitful. 

 Examples— Pol. Angulare (var. strictum_K.) ; Phyl. scolopendrium, var. margi- 

 natum (Wol.), Truncatum, subvariety— frond contracted ; segments either lobed or 

 reduced to a mere midrib ; generally symmetrical ; the apices of the pinnse and pin- 

 nules often truncated, and then unsymmetrical ; nervures as in laciniatum ; generally 

 barren. Examples — Am. ruta mura, subvar. truncate (K.). These groups, especially 

 the variety, present a most extraordinary variety of forms, agreeing all in the one cha- 

 racter of absence of some normal part of'the fern. They appear to be divided into seve- 

 ral groups, according to the element affected, but unfortunately we do not always find 

 the same element affected two successive years. The general type of the class is always 

 adhered to, one year the deficiency occurring in one set of elements, and the next, 

 perhaps, in another ; however, when the substance of the frond is present, we find 

 it cut and lobed, though sometimes it is entirely wanting. The following, or, 

 in fact, any of the elemental parts of the fern, may be wanting. The green colouring 

 matter, the frond variegated and lobed on the edges, as Ph. Scol., var. subvari- 

 gatum (Wol.) ; Aspl. A.N., var. variegatum (W.). The substance of frond ; either 

 in part the frond lobed in various ways ; or entirely the pinnae and pinnules or 

 frond itself reduced to mere lines, as Pol. Ang., var strictum (Kin.). The epider- 

 mis deficient in some way, its edges scalloped and tucked, often pitted and thick- 

 ened ; the apices ending in a spur of fibres, as in the forms marginatum, &c, of 

 Phyl. Scol. and Lomaria spicant, var. marginatum (W.). In fact, every conceiv- 

 able variety of deficiency occurs, and renders the study of numerous examples of 

 this class necessary for the comprehension of the whole. This variety is much less 

 permanent under cultivation than either of the others, but still sufficiently so to be 

 distinguished from the subvariety. Some of its forms are most beautifully symme- 

 trical, in so much that they have been mistaken for species, as the Polystichum, 

 found at Kew, with angularly linear leaflets, which bears the name of Angustatum, 

 and has the habit of producing bulbillaef in the axils of its leaves ; a habit also of a 

 beautiful example of this group exhibited by me before your Society, in 1852, in a 

 plant of Pol. angulare. The Kew plant, or, at least, those plants shown me as 

 such, I believe to belong to Pol. aculeatum, an opinion I know at variance with the 

 generally received one. The preceding remarks, also, in a great measure, apply 

 to the subvariety, in which we find the same irregularities of form — the same 

 occasional symmetrical arrangement of parts — the same tendency to a viviparous 

 reproduction. $ The subvariety in this group is, however, much seldomer fertile 

 than the variety ; it is also very often uniform, but never permanently so. The 

 laciniate subgroup varies more under cultivation than any other, but always 

 keeps sufficiently near to the type to be recognised easily from any other, except 

 the subvariety Truncatum, between which and it some confusion exists at present, 

 principally arising from the groups not having (owing to its ugliness) been as 

 much studied as the Ramose or cristate type, but, doubtless, after alittle more exami- 

 nation, it will be found as well defined as that group. I have prepared a list of all 

 the forms that appear to belong the groups mentioned to-night, but can look on 

 them as, to a certain extent, imperfect, as, doubtless, forms belonging to other groups 

 are mixed up with them, owing to a want of specimens and information about the 

 plants. Indeed, I think, the class themselves are, to a certain extent, only pro- 

 visional, containing within them, probably, the nucleus of other classes. My object 

 has been to collect together all the abnormal forms, and, as far as possible, group 

 them ; how far or how naturally this has been done it must remain for others to 

 judge. A few words about a point of nomenclature. When a variety and sub- 

 variety are found in conjunction it is proposed to call the form by the name of the 

 variety, merely adding after it, u in combination with subvar., &c. ;'' when two 

 varieties or subvarieties are conjoined, either to name it after that best marked, or 

 make a similar addition to that above, or to call it after both, as we speak at pre- 

 sent of " red and white" roses, &c. To the names used some may, and, doubtless, 



* As in Ph. Scolopendrium polyschides (Ray) which possesses a netted venation. 



t This habit of producing bulbils is found in two other species of British ferns— viz., Am. Ruta 

 muraria, where the fronds are generally multifid and fruitful, and in Phyl. Scolopendrium (Galway, 

 Dr Allchin), where the fronds are normal and fruitful. 



t Seen in Polyst. Angulare, vide also Newm. Brit. Ferns., Ed. 3rd., Polystich Ang. varieties. 



