8 PREFACE 



Rothrock. Here, in prosecuting our botanical 

 studies, we broadened our interests to include the 

 ferns. It was in this locality and at this time that 

 Dr. Griffith found the Aspidium aculeatum, 

 variety Braunii, growing in a profusion of beauti- 

 ful sturdy brown clusters at the falls of a little 

 brook which tumbles down through the shales of 

 the mountain on its way toward the North 

 Branch of the Susquehanna River. As this was a 

 lower habitat than any before noted, it was tri- 

 umphantly recorded at a subsequent meeting at 

 the Academy of Natural Sciences of Philadel- 

 phia. Of the joys of this and many subsequent 

 summers ; of the patient hours spent with needles 

 and lens in overcoming difficulties, and the con- 

 stant thumbing, sometimes of Wood's, but gen- 

 erally of Gray's, analytical keys, with the tri- 

 umphs of identification of some hundreds of our 

 native plants of Pennsylvania and adjacent states ; 

 of trips to New Jersey for Helonias bullata and 

 other treasures, and the thrilling memories of the 

 specialized groups of plants found by the sea- 

 shore, my old Gray's Botany, with its marginal 

 notes of time and place of finds, continues to bear 

 mute but eloquent testimony. Nor dare I omit to 

 mention here, among the rarities, the beautiful 

 little Pellaea gracilis found growing at Raines's 

 Falls in the Catskills. These were the days when 

 Rothrock was in his prime; when Thomas Mee- 



