556 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.45. 



tioned by Stur, Solms-Laubach, Schenk, and others, Scott/ who has 

 seen some of the material, inchnes to give it credence. He says: 

 "Each sporangium shows a transverse, or somewhat obUque annulus, 

 just as in that genus [Gleichenia]; though some authors have denied 

 that the apparent annuhis is really distinct from the rest of the spo- 

 rangial wall, the inspection of the specimens, especially those of 0. 

 robustior Stur, leaves no doubt that the former interpretation is 

 correct." 



Briefly, to sum up the arguments for the presence of the Gleiche- 

 niacese in the Paleozoic, it may be admitted that the dichotomous 

 branching can not be taken as proof positive of Gleicheniaceous 

 affinity, but with the fruiting characters the question seems to be on a 

 sUghtly better plane. That the fruit in Oligocarpia is disposed in a 

 circular sorus composed of from 6 to 10 pyriform sporangia, there 

 can not be doubt, but whether they have, or have not, an annulus is 

 perhaps not definitely settled'. If the annulus is indisputably present, 

 this genus should apparently be regarded as closely allied to, if not, 

 indeed, belonging to, the Gleicheniacese, while the absence of the 

 complete annulus would refer it to the Marattiacese. We may con- 

 clude with Seward,^ who says: "We find in Carboniferous types 

 undoubted indications of anatomical and other features which in 

 succeeding ages became the marks of Gleicheniacese." 



The presence of the Gleicheniacese in the Triassic and Jurassic is 

 attested at a number of points, though not all the forms so considered 

 by their authors can always be accepted. Thus, Fontaine's genus 

 Mertensides, from the Upper Triassic of Virginia, is now generally 

 accepted as being Marattiaceous; it lacks the characteristic forking 

 of Gleichenia, but has the 4 to 6 sporangia arranged in a circular sorus. 

 From the Upper Triassic of Basel Leuthardt^ has described a species 

 as Gleichenites gracilis, wliich shows the sori composed of 5 sporangia, 

 each sporangium with a horizontal annulus, and Schenk has figured a 

 species as Gleichenites microphijllus from the Rhaetic of Franconia, 

 but no fruiting organs have been found for it. 



In the Jurassic the forms referred to the Gleicheniacese become 

 increasingly evident, though relatively few have the sporangia pre- 

 served. So many of these have the small rounded pinnules and the 

 dichotomous habit of branching so very like the Gleichenias that there 

 can be Httle or no doubt as to the correctness of their reference to this 

 family. 



In the Cretaceous the Gleicheniacese were evidently well estabhshed 

 and widely distributed, for in the Wealden we find them present in 

 England, Belgium, North Germany, and other locaUties, while in the 



1 studies in Fossil Botany, ed. 2, vol. 1, 1908, p. 290. 



2 Fossil Plants, vol. 2, 1910, p. 351. 



8 Die Keuperflora von Neuewelt bei Basel, Abh. Schweiz. Pal. Ges., vol. 31, 1904, p. 40, pi. 18 ,fig. 3. 



