FLORA OF THE CARBONIFEROUS EPOCH. 



63 



from nearly north-east to south-west. At Granton, one of 

 the specimens exhibited roots. In other places the specimens 

 are portions of stems^ one of them 6 feet in diameter by 61 

 feet in length, and another 4 feet in diameter by 70 feet in 

 length. These Exogenous trees are Gymnosperms, having 

 woody tissue like that of Conifer^e. We see under the 

 microscope punctated woody tissue, the rows of disks being 

 usually two, three, or more, and alternating. They seem to 

 be allied in these respects to Araucaria and Eutassa (Fig. 

 61, p. 74) of the present flora. Araucarioxylon or Pinites 

 Withami (Fig. 49) is one of the species found in Craigleith 



Ficr. 49. 



Fig. 50. 



quarry ; the concentric layers of the wood are obsolete ; there 

 are 2, 3, or 4 rows of disks on the wood, and 2-4 rows of 

 small cells in the medullary rays. Along Avith it there have 

 also been found Dadoxylon medullare, with inconspicuous 

 zones, 2, 3, and 4 rows of disks, and 2-5 series of rows of cells 

 in the rays. Pissadendron antiquum (Pitus antiqua) having 



Fig. 49. Araucarioxylon Withami, Krauss {Pinites Withami), from 

 the Coal-measures, Craigleith, near Edinburgh, showing pleurenchyma 

 with disks, and medullary rays. An excellent specimen of a stem of 

 this pine may be seen in the Edinburgh Royal Botanic Garden. 



Fig. 50. Trigonocarjmm olivmforme, an ovate, acuminate, three- 

 ribbed, and striated fruit or seed, which some suppose to be a 

 sporangium of a Lepidodendron, others refer it to Cycadacese. 

 Hooker refers it to Coniferse like Salisburia. 



