142 Transactions of the Society. 



have a real case of the preservation of Carboniferous Fern-prothalli„ 

 though their career was cut short early.* 



The proportion of Carboniferous "Fern-fronds," however, in 

 which there is any evidence of Fern-fructification, is not, after all,, 

 very large. Out of 147 species of such fronds enumerated in 

 Mr. Kidston's list above referred to, there are only 27 which 

 we can attribute with any certainty to true Ferns, on the ground 

 of fructification. Of the remaining 120, 75 are still altogether 

 doubtful, while in 45 the probability, for reasons to be stated 

 immediately, is all on the side of an affinity with seed-bearing 

 plants. 



In the case of a large proportion of the fronds in question, no 

 fructification had been found until within the last few years. Out 

 of the twenty principal frond-genera,f there is only one, Pecopteris, 

 which consistently gives evidence of Fern affinities by its repro- 

 ductive characters. In the great genus Sphcnoptcris a fraction only 

 of the species is known to have borne the fructification of Ferns. 

 In a few other genera, notably Bhacoptcris and Palceoptcris, repro- 

 ductive organs have been found, and regarded as those of Ferns, 

 but their real nature is dubious. In fourteen entire genera, in- 

 cluding some of the largest and best known, as Alethoptcris and 

 Neuroptcris, referred, to above, there has never been any evidence 

 worth consideration of a fructification which could be referred 

 to Ferns. Yet in cases where such fructification occurs — as in the 

 species of Pecopteris — it is not uncommon, being found, according 

 to Mr. Hemingway, an experienced collector, in about 25 p.c. of 

 the specimens, so that its constant absence from the fronds of a 

 common species affords a strong presumption that the reproduction 

 was not of the ordinary Fern-type. On these negative grounds, the 

 Austrian palrcobotanist Stur, in 1883, definitely expressed his 

 opinion that these fronds, which had never been found with any 

 Filicinean fructification, could not belong to the Ferns, and con- 

 sequently excluded the genera Neuroptcris, Alcthopterisfidontoptcrisy 

 and others, as non-ferns, from consideration in his memoir.J Stur's 

 opinion has been amply justified by the event, but negative evidence 

 by itself can lead to no more than negative conclusions. 



It was from anatomical data that the first positive indication of 

 the real nature of these quasi-ferns was obtained. Three months 

 ago I had the honour of bringing before the Society one of the 

 most important cases of this kind, that of Lyginodendron old- 



* Scott, " Germinating Spores in a Fossil Fern Sporangium," New PhytologUt,. 

 iii. January 1904. 



t Adiantites, Alethopteris, Callipteridium, CaUipteris, Cardiopiteris, Diplotmema, 

 Eremopteris, Linopteris. Lomatopteris, Lonchopteris, Mariopteris, Megalopteris, Neur- 

 opteris, Odontopteris, Palxopteris, Palmatopteris, Pecopteris, Bhacopteris, Spheno- 

 pteris, Txniopteris. 



X " Zur Morphologie und Systenialik der Culm- and Carbonforme," SB. d. K.K. 

 Akad. d. Wiss. zu Wien, Bd. lxxxviii. (1S83) p. 608. 



