320 CALAMARIEAE. 



in this case also seems to me to be highly probable. When Stur a indeed 

 goes on to say that all the Calamitinae may have been the fertile shoots 

 of other ordinary Calamitae, and supposes the character of this group to 

 have been analogous with that of the homosporous Equisetae, he will 

 find none to share that opinion until he succeeds in producing good and 

 sufficient reasons for it. 



The last group is formed of the genus Archaeocalamites, Stur, of 

 which A. radiatus (Bornia radiata, Brongn., Calamites transitionis, Gopp.) 

 is the typical species. The essential character of the genus, as given by all 

 authors, is the constant non-alternation of the broad flat ribs on the cast, 

 in which also the indentations made by the nodes are often not very 

 pronounced and distinct. The rows of small knobs on the nodal line are 

 seldom plainly seen, and authors differ in opinion respecting their relative 

 position, as has been already stated. Casts of this kind, usually round 

 but sometimes pressed flat and without any compact rind of coal, are 

 exceedingly plentiful in the Upper Devonian and Carboniferous systems, 

 and are characteristic of them ; figures of them will be found in many 

 works, in Schimper 2 for example and in Stur 3 . They are usually without 

 branches, but, as more recent authors, Stur and Weiss especially, have 

 pointed out, they are occasionally beset with numerous branch-traces, 

 which are found singly or several together on all successive nodes but 

 without giving signs of any regular order. Weiss supposes that the two 

 pieces may have belonged to different parts of the shoot-system ; in any 

 case the branched specimens must be very rare, for I have never yet seen 

 one of them. 



Our Archaeocalamites occurs in a peculiar state of preservation in the 

 roofing-slates of Moravia. Its remains lie squeezed perfectly flat between 

 the slates ; the organic substance according to Stur 4 ' is replaced only by 

 a very thin, often transparent, brownish membrane, which may have a gold 

 and silver lustre.' Larger stems are very rarely found, and are always in a 

 fragmentary state. But these slates also contain a number of branches 

 which have their appendages attached to them, and show the characters 

 of Archaeocalamites in so striking a manner that Ettingshausen 5 has no 

 doubt that they belong to it. This view has since been confirmed by. 

 Stur's 6 thorough investigation of these remains, and the two authors also 

 refer Sphenophyllum furcatum 7 to the same genus:. The appendages or 

 leaves, as we prefer to call them with Stur and Ettingshausen, are attached 

 to the nodes in many-membered whorls ; they are free and non-coherent 

 down to the base, are narrowly linear, and are branched in a remarkable 



1 Stur (5), p. 169. 2 Schimper (1), t. 24 and (4), t. I. 3 Stur (5), t. I. 4 Stur (6), p. 6. 

 5 von Ettingshausen (7) ; see also t. 2, f. 3. * Stur (6). 7 Geinitz (8), t. i, ff. 10-12, and 



t. 2, ff. i, 2. 



