GYMNOSPERM^. 



127 



England ; and their presence in contemporaneous beds has since been ascertained in 

 France. The British species are Araticarites spharocarjjus, Carr., A. PhiUijJsii, Carr., 

 and A. Brodiei^ Carr., from the Inferior Oohte, and A. Fipiiingfordensis from the Wealden.^ 

 Two of the Jurassic species seem to have shed their scales similarly to the existing trees ; 

 but in the first the cone is unbroken and the scales are seen to have been woody and 

 persistent like those of Araucaria Bidxcilli, though otherwise resembling A. excelsa. 

 The Greensands of Erance have yielded important foliage of undoubted Araucarice, as 

 well as cones, some of the latter as large as any now existing. 



The Taxodie^ form another tribe of remarkable antiquity. The oldest form which 

 can be placed with certainty in it is Voltzia, a genus which appears in the second half of 

 the Permian. Two other genera, Cheirolejns and Schizolepis, occur in the Rhsetic and 

 Lias and are principally known from their small, elongated, and bracteated cones. The 

 singular Rhgetic Palissya is more completely known, the cones being frequently attached 

 to the foliage, which is dimorphic, while the cone is composed of pointed and laterally lobed 

 scales and pointed bracts. Sphenolepis is another fineRha3tic genus with terminal cones 

 clustered together, which survived to the Cretaceous. The genus Swedenhorgia, so far 

 limited to the Rhsetic of Sweden, and Echinostrohus of Solenhofen approach more nearly 

 to the existing genera Cryptomeria and Athrotaxis. The Taxodieoe thus abounded in the 

 Trias, and attained their maximum towards the close of that formation and in the Lower 

 Lias, when they seem to have preponderated over all other plants showing a preference for 

 humid stations. Thenceforward they declined and in the later Jurassics the Cupressinese 

 had already to some extent replaced them. Sequoia^ however, abounded in the Cretaceous 

 period, especially within the Polar Circle, and a Taxodium also appeared before its close. 



One of the most remarkable characteristics of this tribe, according to Saporta, is the 

 tendency to polymorphism in the foliage of every genus belonging to it, not only with 

 regard to different species of the same genus, but also in individual plants. This was 

 especially apparent in the more ancient representatives of the family, and led the earlier 

 authors to assign to different species foliage of Voltzia and Palissya which might have 

 grown on the same tree, so extreme is the range in the size and form of the leaves. In 

 describing the Eocene Taxodieae during the progress of the present work, I have repeatedly 

 called attention to the polymorphism which is apparent in many of them, a peculiarity 

 still manifest in nearly every living species. 



The entire tribe is certainly a declining one at present. The few genera comprised 

 in it are represented by single or few species, and seem all decreasing and retreating 

 relatively to the positions they formerly occupied, while none have maintained themselves 

 in Europe. 



The CuPRESsiNEiE seem to have been first definitely ushered in with the Jurassic 



1 ' Geol. Mag.,' vol. iii, p. 249 ; and vol. vi, p. 3. 



2 Probably the oldest species is described by Carrutliers from the Gault of Folkestone, as Bequoiites 

 Gardiieri, ' Geol. Mag.,' vol. vi, p. 7. 



