1101 



the involucre of the latter." We can scarcely avoid feeling regret 

 that an author entertaining such views should hesitate to carry them 

 out, and should bow to mere authority. We consider it impossible 

 for any one, whatever his skill, to define for the satisfaction of others 

 the genera or tribes known as Trichomanes and Hymenophyllum ; 

 and we hold it needful either to adhere, with Linnaeus, to the genus 

 Trichomanes, or to adopt the generic subdivisions to their fullest ex- 

 tent. For if we divide the Hymenophyllaceae into sections of any 

 kind, more than two such sections will be required; the Didymoglos- 

 seae, for instance, wull occupy a rank at least equal to the Hymeno- 

 phylloideae. A modern writer on Ferns has an apposite passage on 

 this subject ; and it seems not a little remarkable, that a work, so ex- 

 actly supplying the desideratum there pointed out, should be so soon 

 afterwards in the hands of botanists.* 



Genus, Leptocionium, Presl. 



" VensB pinnatEB, simplices, prominulffi, libere desinentes. Sorus terminalis, sessilis. 

 Indusiuin usque fere ad basim Lipartitum suborbiciilatum, laciniis planis appressis 

 margine aequaliter serrato-ciliatis. Receptaculum cylindricum, obtusum, iindique cap- 

 suliferuin, Junius indusio aequilongum, adultum duplo longius nudum cicatriculis ob- 

 longis spiralibus notatum. Capsulae lenticulares, sessiles. 



" Rhizoma repens, filiforme, tenue, hinc inde paleis piliformibus pateniibus ad- 

 spersnm, radicibus flexuosis pilis (vadiculis) horizontalibus vestitis. Frondes sparsse. 

 Stipes semi-uni-pollicaris, teres, flexuosus, fusco-ater, aut glaber aut hinc inde paleis 

 piliformibus adspersus. Frondis limbus semi-sesquipollicaris, lanceolatus, acuraina- 

 tus, basi acutus, margine pilis bipartitis seu dicranoideis crassiusculis ligidis acutissi- 



* Hymenophyllum " was separated by Smith as a genus in the fifth vol. of the Turin 

 Transactions, and the name has been adopted by nearly all subsequent botanists, a 

 strong proof of the weight of Smith's authority, for even now, when generic subdivi- 

 sion has extended to so great a length, we have no new genera founded on such ima- 

 ginary differences as those which separate Hymenophyllum from Trichomanes. In 

 my endeavours to draw a line between these genera, I have been totally unsuccessful : 

 if we regard the exserted receptacle of the one, or the bivalved involucre of the other, 

 the only conclusion at which we can arrive is this — that those species with the longest 

 receptacles at present stand in Trichomanes, those with the most distinctly bivalved 

 involucres in Hymenophyllum. These, however, are mere questions of degree, and are 

 quite insufficient to guide the botanist who — without a prior knowledge of a plant — 

 seeks, by means of books, to ascertain its generic and specific names. It must not, 

 however, be understood that I object to the subdivision of the Linnean genus Tricho- 

 manes ; so far from this, I trust the time is not far distant when some competent bota- 

 nist shall rearrange the entire group, pointing out characters that admit of no dispute, 

 and leading us on to a far more accurate knowledge of these beautiful plants, than we 

 can hope to glean from any works yet before the public." — Newman's British Ferns, 

 p. 323. 



