On the Genera of Fern Trichomanes and HymenophylumAuthor(s): William AndrewsSource: Proceedings of the Royal Irish Academy (1836-1869), Vol. 2 (1840 - 1844), pp. 602-605Published by: Royal Irish AcademyStable URL: http://www.jstor.org/stable/20520207 .

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which I'was previously acquainted, that I was induced to submit it to analysis.+ It occurs in the locality already men tioned, at Rowry, a little to the east of Glandore, in lumps

of variable size, which, when broken, exhibit, though but ill developed, the faces of crystals belonging apparently to the right prismatic system, mixed, however, here and there with what would appear to be a- brown haniatite. Some of the

crystalline portion of the ore, very carefully selected, gave, upon analysis, the following constituents:

-(1) (2) Silex .3.08 Perox. Iron .34.88 0.436 20 Red Ox. Mangan. 50.67 _Sesquioxide 5.25 0.066 3 Oxygen . . . 6.52) Peroxide 51.94 1.188 54

Water .4.85 0.539 24

100.00

These results do not conduct to any very probable formula. But if we suppose that what is set down as sesquioxide is really present as peroxide, a supposition which accords sufficiently well with the analysis, then the composition of this ore becomes very simple, being represented by the formula Fr2 03, HO+3 Mn 0?2, that is by one identical with that which we have found for the psilomelane, when we substitute sesquioxide of iron for the sesquioxide of man ganese. I have no doubt that this represents its real constitution, so that it may be safely set down as a new

and very distinct species. I maiy observe that this mineral answers well for yielding oxygen, but is uneconomical as a source of chlorine, in consequence of the wasteful consump tion of acid, in order to the saturation of the peroxide of iron; one-half in fact of the acid is uselessly expended.

Mr. William Andrews, Secretary to the Dublin Natural History Society, read a paper upon the genera of Ferns

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Trichomanes and Hymenophyltum. His remarks were ebiefly directed to the species of Triclhomanes discovered by him in September, 1842, in the western part of the County

of Kerry, and which presented a variety of growth and state

of fructification so much more developed and characteristic of the genus of that beautiful fern than had hitherto been met withi in Ireland, that determined him to examine its affinities with some of the exotic ferns, particularly with those of the West India Islands.

The Trrichomanes was first discovered in Britain, by Dr. Richardson, at Belbank, near Bin gley, Yorkshire, a wretched specimen of which is in the Banksian Herbarium, now in the

British Museum: a figure of a barren frond is given in Dill.

in Raii Syni. S. p. 127, t. 3. This specimen, however, not

having been found in fructification, was supposed to be identical with the Filix (Trichomanes) pyxidifera of Plu

mier, and was described as such by Hudson, in his Flora

Anglica, p. 461: and this name it retained until its disco

very, in the month of October, 1804, at Turk Waterfall, near

Killarney, by Mr. Mackay, Curator of the Botanic Garden

of Trinity Collegre. Mr. Mackay obtaining this beautiful

fern in fructification, forwarded specimens to Sir James Edward Smitlh, who at once decided its distinctness frotn Plumier's plant, and considered it to be a new species, wlhich he named and figured in English botany as Hymenophyllum alatum, from its winged stipe. The distinguished Robert Brown, the first physiological botanist of the day, corrected this specific appellation to that of brevisetum (Br. in Hort.

Kew. ed. 2, 5, p. 529), from the short and barely exserted

state of the receptacles that the Killarney plants generally presented. Mr. E. Newman, who has devoted so much at tention to the specific characteristics of the British ferns, formed tthe first view, that the Killarney species perfectly agreed witlh Wilidenow's description (Sp. Plant. 5, p. 514) of the Speciosum of Teeneriffe, and published it as such, in

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604

his first edition of the History of British Ferns. The speci fic name brevisetum, however, was still retained through the several editions of the British Flora, until the discovery by Mr. Andrews, in September, 1842, in a wild and wooded glen in the western part of the County of Kerry. The striking characters and fine state of fructification exhibited by these splendid plants, the most rare and most beautiful of British ferns, and now altogether confined to the south western parts of Ireland, Ted Mr. Andrews to examine mi nutely, and to trace their affinities witlh the numerous exotic species of that beautiful genus; and from communications with Sir William J. Hooker, and to the great kindness of that most excellent botanist and encourager of science, and the reference to his very extensive fern herbarium, it was traced and detected to be the true Trichonianes radicans of Swartz, setting aside the species brevisetum of the English flora, and the Speciosum of Willdenow. Thus the mild temperature of the south-western parts of this country pro. duced, in the utmost luxuriance of tropical growth, a plant pe culiar to the West India Islands, and to the western coast of South America. To Dr. Scouler's kindness Mr. Andrews was also much indebted for specimens of Trichomanes radicans, and T. Scandens, collected by Dr. S. in Brazil, and which enabled many doubts to be cleared.

Mr. Andrews noticed a very remarkable character of fructification in the new variety from Kerry, " that the cap sules formed around the base of the receptacles within the cylindrical involucres, and as the receptacles elongated and became exserted coinsiderably beyond the involucres, the capsules continued forming in an even dense mass to the ex tremity of the receptacles." This is described as of rare occurrence in Trichomanes. The Trichomanes reniforme of New Zealand, and the Hymenophyllum fuciforme of Chiloe, are noticed as having the capsules external to the involucres, but their being exposed to view was supposed

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(605

merely to result from the spreading and shrinking of the

valves. Loxsoma appears to be the oinly recorded genus as possessing that peculiarity of fructification.

The specific descriptions of Trichomanes radicans and its synonyma, are fully given in part 2, p. 125, of that invalu

able work, Species Filicum, by Sir J. W. Hooker, recently published.

Professor Allman made some observations on Mr. An drews's paper, in corroboration of its principles.

DONATIONS.

Proceedinigs of the Geological- Society of London. Vol. IV., Part 1. (1843). Presented by the Society.

Bulletin der Kdnigl. Akademie der Wissensciaften zu Munchen. Nos. 1 to 55.

Abhandlungen der Philosophisch. Philologischen Classe dei' Kilniglich Bayerischen Akademie der Wissensekaften zu Munchen. Dritten Bandes dritte Abtheilung, in der Reihe der Denkschriften der XVIII. Band.

Abhandlungen der Mathematisch. Physikalischen Classe der Klniglich Baye-rischen Akademie der Wissenschaften zu Munchen. Dritter Band. Die Abhandlungen von den Yahren, 1837, bis 43, enthaltend. Presented by the Aca demy of Munich.

Versuch einer objectiven Begriindung der Lehre von der Zusammensetzung der Kriafte. Von Dr. Bernard Bolzano. Presented by the Author.

Prodromus za einer neuen, verbesserten Darstellungsweise

der hkhern analytischen Dynamik. Vom Grafen G. Von Buquoy, Ph. D., &c. Presented by the Author.

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