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scriptions uuder the fine name of Aster opJiyJlites.* These Calamites had a 

 rapid development; their stems grew close to each other, forming- 

 dense thickets, like the canes of the southern swamps, which each year 

 rise up impenetrable groves by their compact vegetation. The Calamites 

 appear early in the Subcarbouiferous, even iu the Upper Devonian ; 

 they persist longer, passing up to the Permian, where they are repre- 

 sented by large species of the Equisetum. They have entered by their 

 remains into the formation of all the beds of coal, and in some localities 

 become the essential compound of the combustible matter. 



Some other genera of the Carboniferous flora are represented by floating 

 water-plants of comparatively small size and of more indefinite rela- 

 tions. The more important are the Annularia^ or plants whose branches 

 surrounded the stems, like the ribs of an umbrella, and whose cylin- 

 drical or flat lanceolate leaves, larger than those of the Aster o^phyllites, 

 are, like them, placed in rows around the articulation of the branches, 

 like the spokes of a wheel. The Sphenophyllum also, with stems divided 

 in about the same way as those of the former genus, had their leaves 

 also in whorls, but flat, enlarged upward or wedge-form from the base, 

 and with a nervation analogous to that of the ferns. These two genera 

 represent apparently a family of plants intermediate between the Equi- 

 setacew and the Lycopodiacece. They are widely distributed in the 

 whole extent and thickness of the Coal-Measures, ayd limited to this 

 formation. Like the Calamites, tliey are represented by few species, 

 with, however, a very active and luxuriant vegetation, as indicated by 

 the profusion of their remains. It was the same with the long ribbon- 

 like leaven of Flabellaria, varying from one to three inches broad, which 

 have been remarked upon already iu the Devonian flora. Though their 

 remains are most abundant in the Carboniferous, no plant has yet been 

 found iu connection with its essential organs, the fruit. The leaves 

 embrace at the base a stem of from one to two inches in diameter, but 

 even this stem has been very rarely observed.! The relations of these 

 plants have therefore exercised the researches and ingenuity even 

 of paleontologists without a satisfactory result; for this relation is still 

 as uncertain as when, years ago, the celebrated Corda made the well- 

 known analysis of the texture of a stem. The leaves evidently represent 

 different species, but their characters are uncertain. They have been, 

 described by authors under the name of Flahellaria, Cordaites, etc. ; and 

 now Schimper, in his great work on vegetable paleontology, recalls the 

 old name of Pycnophyllum, formerly proposed by Brongniart. Such are 

 many plants of the Coal-Measures, whose characters and relation are 

 vaguely pointed out by isolated organs, fruits, leaves, or stems, and 

 whose true nature is a secret which may only be revealed by new dis- 

 coveries. The remains of these Flabellariw, which first appear in the 

 Upper Devonian and have numerous representatives of two species in 

 the strata of the Lower Carboniferous, become still more abundant iu 



* Species oi Asttrophyllites are coDsidered by some authors as branches of Calamoden- 

 dron and as referable to the Conifers. 



t Recent researches of Grand'Eury in the coal-basin of St. Etienne, France, seem to 

 prove that the genus Cordaites was represented in the Coal-Measures by numerous species 

 with stems sometimes of 60 to 70 feet high, all bearing long ribbon-like leaves at the top of 

 their branches, and referable by the texture of the stems to the Conifers. To the same 

 naturalist is due the discovery of a large number of fruits referable to the genus Car- 

 diocarpus and lihabdocarpus, preserved in a silicilied state, which have been analyzed 

 by Brongniart, and considered also by him as fruits of Conifers. The same view was ex- 

 posed already in 1870, in the fourth volume of the Geolological Eepoitsof Illinois, p. 493, 

 and the name of Ftilocarpus proposed for the generic clasificatioa of winged fruits ref- 

 erable to Conifers. 



