67 g MR. W. CARRUTHERS ON FOSSIL CYCADEAN STEMS 



was <>iven up by Brongniart in 1849\ when he referred them to Cycade* t but with some 



doubt, as he considered that their true affinities must remain obscure until their internal 



tructure or their foliage was known. Brongniart did, however, in his * Prodrome' 



(1828), establish a genus of fossil Cycads, founded upon stems, to which he gave the 

 name Mantellia. Two species were described — the one from England, the other from 

 Prance. In the same year Buckland communicated to the Geological Society of London 

 his important memoir "On the Cycadeoide*, & family of Fossil Plants," 2 in which he 

 described two species from the Isle of Portland, one of them being the same as the 

 English species of Brongniart. The Cycadean affinities of these stems were clearly esta- 

 blished by both authors, and were further elucidated by Buckland in his 'Bridgevvater 

 Treatise"?. Another British species was added to the genus hy Lindley and Hutton 4 , a 

 fourth by Robert Brown 5 , and a fifth more recently hy myself 6 . 



A fossil figured by Sternberg 7 , and regarded by him as a coniferous cone, by Presl 

 and Buckland 9 as probably Cycadean, and by Brongniart, at first 10 , and Lindley 11 as 

 a Liliaceous stem, was at last referred by Brongniart, in 1849, to its true position among 

 the stems of C vends 12 . 



he only other fossil found in Britain which has been considered the stem of 



*> 



Cycad, is a small fragment figured and described by Corda 13 . Although he believes that 



the specimen was obtained from England, he does not know the locality in which it was 



ori-i'iually found. 



Several forms of Cycadean stems have been recorded from Secondary rocks on the Con- 



tinent. Brongniart, as I have already stated, in his ' Prodrome ' refers a cylindrical stem 



from Luneville to his genus Mantellia. In 1849, Pomel, in a Memoir on the Fossil 



Mora of the Jurassic rocks of Prance 14 , revised the published species, added a new genus, 



Cnmozamia, with three species, based partly on the characters of the stem, and described 



two new species, which he referred, the one to Bucklandia, and the other to Mantellia 

 (Ech inostipes, Pom. ) . 



Gbppert, in 1844 15 , described two Cycadean stems from Silesia, for which he established 

 the genus Raumeria. In a subsequent memoir 16 , he described more fully and illustrated 

 the structure of these fragmentary stems. They are cylindrical and marked with the 

 bases of the leaves, which are separated by quincuncially arranged rhomboidal cicatrices 

 < " scales or stipules." This is unlike any thing in recent Opcode*, but reminded G6p- 

 p't of the arrangement of the scars on some fern-stems, and consequently induced him 

 to estabhan for them a distinct tribe of Cyeade*, with the designation Filicoide*. 



' tw d r,r en ^ ^ V ' g ' taUX F ° SSileS ' P - 9L ' Trans - G ^ S°c. ser. 2, vol. ii. (1829) p. 395. 



-logy and Mme^bgy (1836), p. 490. . The Fogsil Flora of Great ^ voL iL plate 14:3. 



No. xlvi. (1851), p. 130. • Geological Magazine, vol. iv. (1867) p. 199- 



* Tram HoaI 0~T1 IT "I T. "*' * Tentam ^ Floras Primord. (Flora der Vorwelt) (1825), p. 33. 



w Beitra-e zur FW, a tt , " Tabl des Genres <*e Vegetaux Fossiles, p. 91. 



«5itra ff . zur Hora dor \orwelW 1845 Y n f*s ^ — -i ° 



1 roceedingg of the Linnean Society 



Flora dor VnrwnH fo=« ;:; _ or» 



Wimm 



(1849) 



(1853) 



