STIGMARIA. 287 



An abundance of the appendages is to be found in every section of the 

 nodules, even where they contain no axes of Stigmariae. These appendages 

 in the exuberance of their growth have penetrated in every direction through 

 the heap of vegetable fragments which forms the chief mass of the nodules, 

 and they make their way into every crevice and into every bit of softened 

 wood. The hollow medullary cylinders of stems of all kinds are found 

 traversed by them lengthwise, and often by whole bundles of them. Some 

 appendages may inclose a number of others with a narrower lumen (Fig. 38). 

 We saw on p. 273 how in this case they may give rise to mistakes. But all 

 these things prove that they grew luxuriantly in this organic soil, and that 

 they did not merely sink down in it at some later period. As the roots of 

 trees develope abundantly at the present day in the rotten wood of the 

 primeval forests in every zone, and spread abroad in it copiously in every 

 direction, so did the Stigmariae also in the Carboni- 

 ferous period. They are also frequently preserved in 

 the coal of the seams, but then they are always 

 flattened in the planes of stratification ; many 

 instances of this kind will be found in Grand' Eury 1 . 

 The flattening took place therefore after the formation 

 of the calcareous nodules in the masses that were laid 



FIG. 38. Transverse section 



in their final resting-place, and while these were m the of the appendage of a sd g - 



A 1-11 maria, in the cavity of which 



act of subsiding. Stigmariae must accordingly have are other appendages which 



. have made their way in from 



been continually present during the formation of the the outside; a internal cylin- 

 der and bundle of the inclos- 



seams. and on the spots where they were being formed, ing appendage b the other 



appendages inside it, one of 



And, to sum up briefly what has been said, if the which shows yet another which 



* J has forced ; way into it. 



Stigmariae were adapted to grow at one time in After Renault (10). 

 the inorganic slime of the later underclays, presumably at the bottom 

 of the water, and at another time in the organic mass of the seam 

 itself, in the latter case perhaps forming part of the matted growth covering 

 the surface of the water in the coal-swamps, it is plain that they must have 

 possessed a developed faculty of adaptation to external circumstances of 

 very different kinds. 



With this result the physiologist may rest content ; morphology must 

 institute some further enquiries into the character of the separate members 

 of the stock in Stigmariae. Here again opinions are widely divided. 

 Brongniart 2 himself had remarked that some of their characters do not 

 quite agree with those of recent roots, and though he does not think that 

 this is a matter of much importance, still he says : ' The only fact 

 which is opposed to this view is that the rootlets are not disposed in 

 limited longitudinal rows, but in quincunces.' Then Schimper 3 insisted 



1 Grand' Eury (2), pp. 144, 150. * Brongniart (2), p. 105. 3 Schimper (1), vol. ii, 



Part I, p. in. 



