664. 



HISTORY OF THE VEGETABLE KINGDOM. 



substance is destroyed, there are strongly marked 

 rhoraboidal sjiaces looking like scars. These 

 heads are rare, though the fragments of the plant 

 are in abundance. The fossils are much larger 

 in size than any recent allied species. In the 

 specimen figured in the cut, the coire is upon 

 the main stem, but cones are also found in the 

 lateral branches. These cones verjr much resem- 

 ble those described under the name of lepidos- 

 trobus, and the plants may have been similar. 



Conifers. A considerable number of fossil 

 species of coniferas have been discovered, both 

 in the secondary and tertiary strata. It is only 

 within the last few years, however, that species 

 of the true coniferje, analogous to existing pines 

 and araucarias, have been identified in the coal 

 measures. Large trunks of trees have been 

 found in the sandstone strata, near Edinburgh, 

 as well as in the Newcastle coal fields, which, 

 from the pecularity of their internal struc- 

 ture, leave no doubt of their having been of the 

 pine tribe. The peculiar structure of the coni- 

 ferse, has already been alluded to and illustrated 

 by the figure in Plate I. By these it will be 

 seen that the transverse sections of such woods, 

 in addition to the usual medullary rays and 

 concentric lines of annual growth, exhibit under 

 the microscope a system of reticulations, by 

 which they are distinguishable from all other 

 plants. In longitudinal sections again, a sj'stem 

 of vessels called discs, with central areola;, are 

 also visible, and these varj^ in the different ge- 

 nera, so as to afford data for the discrimination 

 of the araucarias from the other coniferae. This 

 discovery is due to the ingenuity and perseve- 

 rance of William Nicol, Esq. of Edinburgh.* In 

 some conifersE, the discs are in single, and in 

 others in double and triple rows. Throughout 

 tiie whole family of existing pines, where double 

 rows of discs occur, the discs of both rows are 

 placed side by side, and never alternate, and the 

 number of rows of discs is never more than two. 

 In the araucarias, the groups of discs are arranged 

 in single, double, triple, and sometimes quadru- 

 ple rows. They are generally smaller than those 

 ill the true pines, about half their size, and in 

 the double rows, thej'' always alternate wii h each 

 other, and are sometimes circular, but mostly 

 polygonal. Mr Nicol has counted a row of not 

 less than fifty discs in a length of the twentieth 

 part of an inch, the diameter of each disc not 

 exceeding the thousandth part of an inch; but 

 even the smallest of these are of great size, when 

 compared with the fibres of the partitions bound- 

 ing the vessels in which they occur. A fossil 

 trunk of an araucaria was found in Craigleith 

 quarry, near Edinburgh, in 1830. Another 

 mass twenty-four feet long, and three feet in dia- 

 meter, was partially exposed in the same quar- 



* Edin. Pliil. .Tom-nal. 



rics, in 1880, and a third in the Wardie quar- 

 ries in 1839. The longitudinal sections of these 

 trees exhibit a structure exactly similar to the 

 sections of the recent araucaria excellsa, that is, 

 there are small polygonal discs arranged in dou- 

 ble, triple, and quadruple rows, with the longi- 

 tudinal vessels. 



Specimens of the coniferae are not uncommon 

 in the lias and oolite formations; and Brong- 

 niart has enumerated twenty species in the 

 tertiary strata. Branches of the araucaria, with 

 the leaves still adhering to them, have been found 

 in the lias of Lj'me Regis. 



A portion of the araucaria peregrina wasfound 

 in the lias of Lyme, Dorsetshire. It is a very 

 perfect specimen of a branch with the imbricated 

 leaves, which are larger and blunter than the a. 

 exceha of Norfolk island, but in other respects re- 

 markably similar. Mr Nicol remarks, that in fos- 

 sil woods from the Whitby lias, where concentric 

 layers are distinctly marked on their transverse 

 section, the longitudinal sections have also the 

 structure of pines ; but when the transverse sec- 

 tion exhibits no distinct annual layers, or has 

 them but slightly indicated, the longitudinal sec- 

 tion has the characters of araucarias. So also 

 those coniferae of the coal formation of Edin- 

 burgh and Newcastle, which exhibit the struc- 

 ture of araucaria in their longitudinal section 

 have no distinct concentric layers, whilst in the 

 fossil coniferae from the New Holland and Nova 

 Scotia coal field, both longitudinal and transverse 

 sections agree with those of the recent tribe of 

 pines. 



a Lyoopodites. williamsonis. 

 Q Trigouocarpum noggerathii. 

 ec CarpoUtlies conica. 

 g Lepidodendron oocephala. 



h Piiius priinoEva. 

 d Pinus cinarieusiB. 

 / Zamia ovata. 

 liU CarpoliUies. 



Fig. (Z is a cone oi pinus canariensis, found in 

 tertiary strata in Spain, and apparently analo- 

 gous to pines at present growing in the Canary 

 islands. 



Palms. Evident traces of the branches of palm 

 trees have been found in the coal formations, and 

 some fossil fruits, which bear a strong resem- 

 blance to the cocoa-nut and date, though of a 

 diminutive size, have been obtained in good pre- 

 servation from the Newcastle coal fields. (Fig. 

 c cut 238,) represents one of these fruits in 



