56 



this genus (Psaronius) are referred stems of tree ferns, cov- 

 ered at the inferior parts by adventive roots, increasing by 

 their superposition the conical base of the trunks." To this 

 Sir Wm. Dawson gives an ideal figure in the Quarterly 

 Journal of the Geological Society, Aug. 1871, on Caulopteris 

 peregrina, Nevvb. as seen in the diagram. 



Having corresponded with Mr. Dawson on this subject, 

 he encouraged me in making further researches and said 

 that it would be a matter of great interest to find a part of 

 the cylinder attached to a fragment of the stem. I was not 

 long in finding such. In my collection I have nine upper 

 terminal parts of Psaronius. They all show a truncate 

 crown with a craterlike depression and a central supposed 

 cylinder of a fern. Among all the specimens I did not find 

 a conic contraction to give evidence of aerial roots. Instead 

 of roots converging toward a cylinder, there are evidences 

 of upward diverging vascular arrangements. In a descrip- 

 tion of one given a few years ago with an illustration in the 

 American Geologist, for which I was severely assailed and be- 

 fore I was in possession of present evidences, I described 

 this plant as having terminated with a crown of reed-hke 

 issues. From descriptions read of Psaronius I could not 

 possibly judge from my then single specimen that it was a 

 species of that erroneously described genus and named it 

 Wiiichellina fascina, which Dawson is inclined to consider a 

 subgenus, because from the two specimens sent him he 

 could not fully comprehend the supposed character of 

 Psaronius. 



Among the six or more different species in my possession, 

 all essential characteristics are presented and some differ re- 

 markably from others in their tubulo-vascular bundles and 

 central arrangements — the thorough siHcification of them has 

 minutely preserved their cellular structure. 



I. In the first place they, are plants of low growth, being 

 about six feet in height. 



