STIGMARIA. 



285 



any considerable previous elongation. And the like may certainly be as- 

 sumed in the case of all specimens in which numerous lateral branches 

 spring immediately from the base of the stem, and among them of Binney's 

 and Harkness' l stems from St. Helen's, of Rich. Brown's 2 of the year 1849 

 from Cape Breton, of the stem in the Museum at Bonn from the Holz- 

 hauerthal near Saarbriicken described by Goppert 3 , and of the stem quite 

 recently found near Bradford 4 (Fig. 37 A), for a photograph of which taken 

 on the spot I am indebted to the kindness of Mr. Cash. The repeated 

 dichotomy is most clearly seen in the two last specimens and in one of 



FIG. 37. Stumps of stems of Sigillaria with Stigmariae attached. A the stump lately found near Bradford ; its 

 breadth from north to south is 29$ English feet, from east to west 28 English feet. B stump of a stem with four 

 diverging roots forming a cross, and showing the character of Stigmariae, seen from the side and from below. 

 C stump of stem of Sigillaria with many Stigmariae repeatedly and dichotomously branched and preserved up to their 

 extremities, seen from the side and from below, and showing in the latter view the conical processes (tap-roots) 

 mentioned in the text, which are placed at the base df each bifurcation and go vertically downwards. At one spot in 

 this stem there is an appearance of something like Dictyoxylon-structure. A after a pencil sketch by Williamson. 

 B after Williamson (6). C after R. Brown (3). 



Brown's, and was duly noticed in the description of the Bonn stem given 

 by Weber and printed by Goppert 5 . 



A special peculiarity is observed in one of Brown's 6 stumps (Fig. 37 

 C}. On the under side of its Stigmariae are blunt conical processes directed 

 vertically downwards, and with their surface covered with transverse wrinkles 

 of apparently accidental origin. The discoverer notices particularly that 

 they are arranged in two circles, the inner containing sixteen processes, the 

 outer thirty-two. The figure it is true does not point to these numerical 

 relations, but it shows that each process, a ' tap-root ' according to Brown, 



1 Binney and Harkness (5). 

 * Williamson (6), t. 15. 



2 Brown, Rich. (3). 3 Goppert (20), t. 12 and (3), t. 37, f. 2. 

 Goppert (20). Brown, Rich. (3). 



