W. Carruthers — Notes on Fossil Plants. 51 



the fossils are contained, account for the imperfect preservation of 

 the minute structures. 



The interpretation which T have here given of the fructification of 

 this interesting fossil, exhibits so close a resemblance to what we find 

 in the living genus HymenopJiylliim, that, were it not for the vegeta- 

 tive portions, I would without hesitation place it in that genus. But 

 inasmuch as the arborescent Lycopodiaceoe of the Palaeozoic rocks, 

 while agreeing in all the essential parts of their reproductive organs 

 with particular existing genera of the order, as I have elsewhere 

 shown, are properly placed in distinct genera, so this fern, removed 

 in precisely the same way from the known living forms, requires a 

 generic designation. The large size and obviously firm texture of 

 the frond is in remarkable contrast with those membranaceous fronds 

 of the living forms which have secured for them the popular name 

 of " Filmy Ferns." But the New Zealand genus Loxsoma has large 

 decompound sub-coriaceous fronds, and though on this account it is a 

 somewhat aberrant form, nevertheless the cup-shaped involucre, free 

 central receptacle, and sessile oblique-ringed sporangia, place it 

 beyond doubt among the HymenopliyllecB. In the form of the pinnules, 

 Loxsoma is not unlike Falceopteris ; the venation of the fossil is 

 however more flabellate, and the veins are more numerous and equal- 

 sized ; but that there is a true though indistinguishable costa in each 

 pinnule, as in Loxsoma, is obvious from the fertile pinnee, wliere the 

 pinnule is reduced to the much-enlarged costa with the short veins 

 bearing the cysts. This absorption of the parenchyma in Falceopteris 

 is very different from what occurs in Loxsoma ; but in the small 

 Central American Hymenophyllaceous genus Feea we find the fertile 

 frond reduced to its rachis, with a series on either side of short 

 pedicels (representing the costee of the segments) supporting each a 

 Trichomanoid cyst. The uniform flabellate veins, which suggested 

 to Brongniart the genus Adiantites, though not the familiar form 

 of venation in the Filmy Ferns, do occur in some species, especially 

 among the simple fronded forms. 



2. Sporangia of Ferns in the Coal-measures. 



I have met with an interesting confirmation of the existence of 

 true Hymenophyllece in Palaeozoic formations in the discovery of 

 Sporangia belonging to this group of Ferns in the Coal-measures. 

 The sporangia are the cases in which the spores are formed. They 

 are divided into two great groups, by the presence or absence of an 

 elastic ring, technically called an annulus. The annulate sporangium 

 consists of a cellular sac, an articulated ring, which is either vertical 

 (Folypodiece) , oblique (Hymenophyllea and Cyathece), or horizontal 

 (Gleicheniacece), and generally a pedicel. The articulated ring is 

 hygrometrically elastic, and, when the capsule is ripe and the atmo- 

 sphere dry, it tears the little sac and lays it open with such a sudden 

 spring as to scatter the spores. In the vertical-ringed sporangia, the 

 ring is continued into a long slender pedicel (Fig. 7). Those with 

 ,oblique rings are attached to th ; receptacle by the cellular substance 

 -of the sac (Cyathece), or by a short thick pedicel developed from the 

 sac (Hymenophylleoi) , Fig. 6. The sporangia which I have obtained 



