PRB-CARB0NIFER0U8 PLANTS. 



61 



112. Cardiooarpum obliquum, Dn.— (PI. XIX, Figs. 225, 226.)— J. 

 G. S., XVIII, 824; PI. XIII, Fig. 25.— M. D., St. John, New 

 Brunswick. 



*' Unequally cordate, acuminate, smooth, with a strong rib passing down 

 the middle ; length about three lines." 



This species may have been of different character from the preceding, or 

 may have been a nucleus deprived of its invest'ucnts. 



All of the above species of fruits agree in having a dense coaly nucleus 

 of appreciable thickness, even in the flattened specimens, and surrounded 

 by a thin and veinless wing or margin. They have thus precisely the ap- 

 pearance of samaras of many existing forest trees, some of which they also 

 resemble in the outline of the margin, except that the wings of samaras are 

 usually veiny. They are in like manner very similar to the Cardiocarpa 

 of the coal-formation. The character of the nucleus and the occasional 

 appearance in it of marks possibly representing cotyledons or embryos, 

 forbids the supposition that they are spore-cases. They must have been 

 fruits of Phacnogams. Whether they were winged fruits or seeds, or 

 fruits with a pulpy envelope like those of Cycads and some Conifers, may 

 be considered less certain. The not infrequent distortion of the margin is 

 an argument in favour of the latter view, though this may also be supposed 

 to have occurred in samaras partially decayed. On the other hand, their 

 being always apparently flattened in one plane, and the nucleus being 

 seldom, if ever, found denuded of its margin, are arguments in favour of 

 their having been winged nutlets or seeds. Until recently I had regarded 

 the latter view as more probable, and so stated the matter in the second 

 edition of Acadian Geology. Last winter, however, when examining the 

 collection of Dr. Newberry, in New York, that accomplished palaeontologist 

 pointed out to me the close resemblance between some fruits of this kind 

 from the Carboniferous of Ohio and the drupaceous fruits of a recent 

 Cycad. Re-examining the numerous specimens in Prof. Hartt's collection 

 with this additional light, I have arrived at the conclusion that the 

 Cardiocarpa of the type of 0. cornutum were Gymnospermous seeds, 

 having two cotyledons imbedded in an albumen and covered with a strong 

 membranous or woody tegmen surrounded by a fleshy outer coat, and that 

 the notch at the apex represents the foramen or micropyle of the ovule. The 

 structure was indeed very similar to that of the seeds of I'axus and 

 of Saliaburya. In Plate XIX, Figs. 216 and 217 show very well the 

 nucleus with its cotyledons and investing tegmen, while Fig. 218 shows 



