THE FLORA OF THE COAL FORMATION. 459 



its being covered with Sjrirorbis, I think it must either have been of 

 more aquatic habit than most of the other plants of the Coal Forma- 

 tion, or that its leaves must have been very durable. "While the 

 leaves are abundant, the stems are very rare. I infer that they were 

 usually low and succulent. Much of the tissue found in the coal, 

 which I have called u epidermal," probably belongs to leaves of 

 Cordaites (Fig. 172). 



In the Upper Coal formation there is a second species, distinguished 

 by its simple and uniform venation. This 1 have named C. simplex. 



4. Sporangites. — To avoid the confusion which envelopes the clas- 

 sification of Carpolites, I have used the above name for rounded spore- 

 cases of Lepidodendron and allied plants, which are very frequent 

 in the coal. A smooth round species like a mustard-seed is exces- 

 sively abundant in the Lower Carboniferous at Horton, and probably 

 belongs to Lepidodendron corrugatum, with which it is associated. 

 A species covered with papillae, S. popillata, constitutes nearly the 

 whole of some layers in coal 12, group xix. of the Joggins section. 

 I have no indication as to the plant to which it may belong, except 

 that it is associated with Cordaites (Fig. 173, L). 



Fruits, Flowers, etc. 



1 . Antholithes, Brongn. — Spikes of fruits protected by bracts, and 

 which I believe to have been produced by Sigillarioid trees (Fig. 

 173, A, B, C). 



2. Trigonocarpwn, Brongn. — Nut-like fruits, often three or six 

 angled; with a structure akin to those of Pines and Cycads. I 

 believe most of them to have belonged to Sigillaria, some possibly to 

 conifers (Fig. 173, D, E, F, and Fig. 174). 



3. Rhabdocarpus, Goeppert and Brongn. — Oval fruits with striated 

 sides, often of large size, but of uncertain affinities (Fig. 173, G). 



4. Cardiocarpum, Brongn. — Fringed or margined fruits resembling 

 Samaras of elms. Their precise origin is unknown. They may have 

 belonged to upland trees, of which" we have no other evidence in the coal 

 swamps. It is to be observed, however, that in books of fossil botany, 

 many organisms, which are probably spore-cases of Lepidodendra or 

 allied plants, are confounded with true Cardiocarpa (Fig. 173, I, K). 



With the exception of a few other genera based on parts of plants, 

 like Cyperites and Stigmaria, and two specimens referred to Nceg- 

 gerathia (Fig. 73), and Diplotegium (Fig. 172, B), genera of uncer- 

 tain affinities, the above will include all the plants that have as yet 

 been found in our Coal formation ; and they are the characteristic 

 genera of the Carboniferous period throughout the world. 



