28 



BRITISH EOCENE FLORA. 



Chrysodhm have c[uite recently been met with by Saporta in the Gypsum of Aix, from 

 which more than 300 forms of plants have been collected. This undescribed species has 

 been minutely compared by Saporta with specimens of the Bournemouth Chrysodium, 

 and he pronounces them to be specifically the same, although the Aix specimens are 

 somewhat smaller. The venation is shown by Saporta's drawings to be identical. 



The distribution of Ch. Lavzoeanum is consequently extended in Europe to the Middle 

 Eocene of Monte Promina, the Upper Eocene of Aix, and possibly to the Aquitanian of 

 Manosque. The fossil species appears, therefore, to have had a wide range like the 

 existing one ; a fact in accordance with its exceptional range and abundance iti the 

 English Eocenes. 



The presence of (Jltri/sac-iiDit in Europe so late as the Middle Tertiary period has thus 

 been ascertained by numerous specimens, most of them of very recent date. 



Saporta and Ilecr have also detected a resemblance in the Eocene species to Gymno- 

 yrainwa Gardiieri, Lesquereiix indeed, Saporta had suggested this affinity" to Les- 

 quereux during the publication of his work. Lesquereux, however, informs me, after 

 comparing the specimens which I forwarded to him, that, although a considerable 

 correspondence exists, the venation in his species is much looser, and the midrib is of a 

 different type. With reference to Lesquereux's determination of the American species as a 

 Gymnogramma, Heer thinks it still doubtful, until fructification shall have been found, 

 whether all the species belong to that genus {Bictyoyranuiia, Eee.), or to Chrysodium. 



Chrysodiim Lanzaanwni is locally abundant, ranging from the Lower Bagshot through 

 the Bournemouth Beds, and is met with in the marine beds overlying them, and at 

 Ilordwell. It is exceedhigly common in beds on both sides of Bournemouth Pier, and 

 scarcely less so in the widely separated beds at Studland. 



De-la-Harpe mentions a small fragment in Prestwitch's Collection, and to which he 

 doubtfully attached the name Acrostichum, as having been obtained at Alum Bay ; but 

 its occurrence there has not since been confirmed. Usually only torn, twisted, and 

 detached fragments are met with ; and the specimen figured in PI. I, from a bed of 

 black clay under the Coastguard Station at Bournemouth, is the only one in which the 

 pinnas have been found attached. No traces of fructification have yet been detected. 

 Carruthers, being present when the larger specimen was found, ixnmediately recognised 

 its affinity to Chrysodium vulgare. This alliance has also been admitted by Hooker and 

 other English botanists who have seen it, so that the correctness of the determination, 

 due in the first instance to Carruthers, is unquestionable. 



The specimens figured, PI. II, figs. 3, Sa, 4, are from Studland ; PI. II, figs. 1, \a, 

 2, 2«, and PI. I, are from Bournemouth. In the former the secondary veins are more 

 closely set. 



^ ' Tertiary Flora of America,' p. 58, pi. 4, fig. 2. 

 - Op. cit„ p. 58. 



