24 rnOCEEDINGS OF TUE 



between the plants oE tlie root-nodules and those of the seain- 

 nodules in Lancashire coal beds is clearly due to ditVereiit 

 conditions rather than to different age. Like lirongniart, be 

 expresses his regret that *' we unfortunately still possess no 

 botanical work in which the internal structure of the races of 

 jdants is characterised. In this respect it would be especially 

 desirable to know accurately the internal structure of the stems 

 of Palms and Tree-ferns, which in the forests of America grow 

 into such gigantic trees" (p. 7). lie realised the difficulty of 

 naming the fragmentary fossil remains without the risk of bringing 

 the 8ei)arate jiarts of one and the same plant inider different 

 species. He bases his own arrangement on internal characters, 

 not that he considered these the best (though they might be so if 

 the anatomy of recent plants were better known), but because no 

 other characters were available in his petriiied specimens. He 

 realised that there are whole fossil families which no longer exist, 

 80 far as is known, in the liA^ing Creation (p. 11). 



Cotta's classification was rudimentary. He divided his speci- 

 mens into three groups : Khizomata, Stipites, and Eadiati — a 

 classification of fossils rather than of plants. 



His first group he calls the rhizomes of extinct Ferns, in which 

 he was roughly right. His genus Tuhkanlis, of Permian age, 

 may be said to correspond to the family Zygopteridese, as under- 

 stood by the latest writer, Paul Bertrand. This is a group of the 

 early Ferns — Primotilices of ]\[r. Arber — of which so much has 

 been heard of late. Before Cotta, these fossils had been placed 

 in the Palms, thouah D. Anton Sprengel had already called them 

 "exotic Perns." The genus Tuhicaulis, as now limited, includes 

 one only of Cotta's species, based on a single, very fine specimen 

 which had been discovered in 1815. A second specimen of a 

 distinct species was brought to light in Lancashire nearly a 

 century later, and described by Dr. Marie Stopes. Cotta 

 nowiiere distinguishes clearly between the petioles and the true 

 stem of these plants. 



He follows his predecessor D. A. Sprengel in classing Psaronius 

 (also Permian) with Ferns, and in this respect did better than 

 Brongniart. The name " fStarling-stones" for these ornamental 

 fossils is familiar ; it may not be so generally known that this 

 name properly applies only to the specimens showing the roots ; 

 those in which the long, curved sections of the vascular bundles 

 of the stem are visible used to be called " Maggot -stones," 

 "Madensteine," ^^ Psaronius hehnintliolithns.'" In earlier days 

 these fossils had been regarded as Corals or Encrinites. 



In certain cases Cotta recognised the roots as such, though he 

 more often interpreted the same bodies as leaf-stalks. 



His second group — Stipites or Trunks — includes fossil stems 

 from much later rocks, which he rightly classed as Palms. 



The third family, Eadiati, or radiately striated stems, is of 

 considerable interest — it embraces, as one might judge from the 

 family-name, stems with secondary thickening. He says that 



